ppxscal/embedding_network huggingface dataset:
Set Operations for Unaligned Linear Quadtrees
Authors: Clifford A. Shaffer, Hanan Samet
Venue:  (1988)

An algorithm is presented that performs set operations (e.g., union or intersection) on two unaligned images represented by linear quadtrees. This algorithm seeks to minimize the number of nodes that must be searched for or inserted into the disk-based node lists that represent the trees. Windowing and matching operations can also be cast as unaligned set functions; these operations can then be solved by similar algorithms.
SOURCE-LEVEL DEBUGGING OF OPTIMIZED CODE: DETECTING UNEXPECTED DATA VALUES (M.S. Thesis)
Authors: Max Copperman
Venue:  (1990)

Optimizing compilers produce code that impedes source-level debugging. After optimization, the correspondence between a program''s source code and object code is not straightforward. This thesis provides a solution to one of the more difficult source-level debugging problems caused by optimized code. The first third of the thesis examines the problems caused for source-level debuggers by optimization and presents a detailed survey of previous research in the area. It is noted that some of these problems are not difficult, but remain problems due to inertia in the production-software development process. The final two-thirds of the thesis develop a solution for one of the difficult problems examined in the first part of the thesis. The problem is that of determining when optimization has caused a variable to contain an unexpected value, that is, a value that differs from the value one would expect it to contain from an examination of the source code. More formally, at a breakpoint in an executing program, a variable contains an unexpected value if its value results from a different computation than in an unoptimized version of the program stopped at an equivalent breakpoint. This is detected by having the optimizing compiler provide information about how variable definitions in the optimized code differ from variable definitions in the source code. In particular, the compiler creates records for each statement in the program which are referred to by pre- and post-optimization versions of the program flow graph. By comparing reaching definitions computed on the two versions of the flow graph, unexpected values can be detected. The solution is effective (and uniform) for both local and global optimizations and is largely independent of the particular optimizations that have been performed.
A Taxonomical Review of Object-Oriented Simulation Model Verification and Validation Techniques
Authors: Yilmaz Levent
Venue:  (1998)

The goal of this paper is to provide a taxonomical review of verification and validation (V&V) techniques for assessing the accuracy of object-oriented simulation models and to present guidelines for the selection of the techniques based on their effectiveness and costs. The techniques are evaluated based on the identified indicators that relate the techniques to their error detecting capability and the costs that measure the ease-of-use aspects. The paper introduces a preliminary object-oriented model fault taxonomy based on a comprehensive literature survey and authors'' experience. The fault taxonomy not only compares and contrasts the error detection capabilities of the techniques but also provides a basis and guidance for detecting specific faults likely to occur due to complexities of object-oriented paradigm such as object/class hierarchies. state-dependent behavior, dynamic and diverse patterns of interactions, among the objects. The guidelines and the comparative analysis of the object-oriented V&V techniques allow practitioners to select the techniques based on the benefits and costs.
Uncertainty and Probability
Authors: Jane T Nutter
Venue:  (1986)

Advocates of probability theory as a primary tool for reasoning in contexts of uncertainty and incomplete information have increased in number in recent years. At the same time, opponents have put forward a variety of arguments against using probabilities in this field. This paper examines the relationship between probability theory and reasoning in uncertainty, and argues that (contra opposing views) probability theory does have a place, but that its place is more restricted than many of its advocates claim. In particular, two major theses are presented and argued for. (1) Reasoning from probabilities works well in domains which permit a clear analysis in terms of events over outcome spaces and for which either relatively large bodies of evidence or long periods of "kaining" are available; but such domains are relatively rare, and even there, care must be taken in interpreting probability results. And (2) some generalizations with which AI applications must concern themselves am not statistical in nature, in the sense that statistical generalizations neither capture their meanings nor even preserve their truth values. For these contexts, different models will be needed.
Fast adaptive calculation of invariant features
Authors: Sabine Kroner, Hanns Schulz-Mirbach
Venue:  (1995)

The paper presents algorithms for the fast adaptive calculation of invariant features. These are pattern characteristics that remain unchanged under the action of a transformation group. First it is explained how to construct such features by integrating complex valued functions over the transformation group. Motivated by this technique we devise algorithms for adaptively calculating invariant features especially suited for a given application. The basic tool is a new network structure with adaptable nodes allowing the fast calculation of an invariant feature with the computational complexity of cal O(N) (N the size of the input data). The algorithms have been implemented and tested both on real and synthetic data. By an experimental comparison with other techniques for calculating invariants we elucidate the abilities of our adaptive algorithms.
Adaptive FEC for Reliable Multicast
Authors: X. B Zhang, Yang R Yang, Simon Lam
Venue:  (2001)

Proactive forward error correction (FEC) has been widely used to improve reliability and reduce latency. How to determine the proactivity factor for a proactive FEC based protocol, however, has not received much attention. If the proactivity factor is too large, the sender may experience high bandwidth overhead. On the other hand, if the proactivity factor is too small, the receiver(s) may experience long recovery latency. In this paper, we study how to adaptively adjust proactivity factor for reliable multicast by observing the number of NACKs returned to a multicast sender. By controlling the number of NACKs, we strike a balance between small recovery latency for the receivers and small bandwidth overhead for the sender. In particular, our fast adjusting algorithm, which is applied at the beginning of a multicast session, can quickly control the proactivity factor so that the number of NACKs is around the target value. Our dual tuning algorithm, which is applied after the fast adjusting algorithm, can further reduce the fluctuations of the number of NACKs. Our simulations show that these two algorithms not only can effectively control the number of NACKs, but also can maintain small sender bandwidth overhead and significantly reduce receivers'' recovery latency.
Once More Unto The Chinese Room
Authors: Mike Alder
Venue:  (1990)

It is well known that there is a debate going on concerning the nature of minds, the feasibility of Artifical Intelligence and whether one has a bearing on the other. The latest example at the time of writing is the pair of papers in the January 1990 issue of Scientific American. The paper on which this paper comments in John Searle''s "Is the Brain''s Mind a Computer Program?". This is the current installment in the Chinese Room saga, and the present paper attempts to terminate the sequence by pointing out certain features of the kinds of arguments used, features which make the enterprise upon which Searle is engaged sterile.
A Semi-Automatic Approach to Protocol Implementation --- The ISO Class 2 Transport Protocol as an Example
Authors: Allen C. Lau
Venue:  (1986)

Formal Description Techniques (FDTs) for specifying communication protocols, and the adopted FDT standards such as Estelle have opened a new door for the possibility of automating the implementation of a complex communication protocol directly from its specification. After a brief overview of Estelle FDT, we present the basic ideas and the encountered problems in developing a C-written Estelle compiler, which accepts an Estelle specification of protocols and produces a protocol implementation in C. The practicality of this tool --- the Estelle compiler --- has been examined via a semi-automatic implementation of the ISO class 2 Transport Protocol using the tool. A manual implementation in C/UNIX 4.2bsd of this protocol is also performed and compared with the semi-automatic implementation. We find the semi-automatic approach to protocol implementation offers several advantages over the conventional manual one. These advantages include correctness and modularity in protocol implementation code and reduction in implementation development time. In this thesis, we discuss our experience on using the semi-automatic approach in implementing the ISO class 2 Transport Protocol.
Symmetry in Self-Correcting Cellular Automata
Authors: Nicholas Pippenger
Venue:  (1992)

We study a class of cellular automata that are capable of correcting finite configurations of errors within a finite amount of time. Subject to certain natural conditions, we determine the geometric symmetries such automata may possess. In three dimensions the answer is particularly simple: such an automaton may be invariant under all proper rotations that leave the underlying lattice invariant, but cannot be invariant under the inversion that takes each configuration into its mirror image.
AN ITERATIVE APPROACH FOR DELAY-BOUNDED MINIMUM STEINER TREE CONSTRUCTION
Authors: Qing Zhu, Mehrdad Parsa, Wayne W.M. Dai
Venue:  (1994)

This paper presents a delay-bounded minimum Steiner tree algorithm. The delay bounds, given as inputs to the algorithm, can be different for each individual source-sink connection. The approach is based on feasible search optimization that satisfies the delay bounds first, then improves the routing tree for the cost minimization. Iterative cut-and-link tree transformation constrained by delay bounds provides an efficient technique to reduce the cost. Once reasonable delay bounds are set, this algorithm constructs Steiner trees with the correct timing, and by experiments the costs are always less than the trees obtained by a well-known, provably near-optimal Steiner-tree heuristic within the factor 2(1-1/|S|) of the optimal Steiner tree for |S| sinks. In order to satisfy given delay bounds, we also propose a new algorithm to construct a maximal-delay-slack tree based on the global information of sink delay slacks. The use of our algorithm is especially attractive for deep-submicron VLSI layout or MCM substrate layout where the interconnect resistance is comparable to the driver on-resistance, when the minimal delay tree may have an unacceptably high cost while the traditional minimum Steiner tree fails the delay requirements.
Population Diversity and Fitness Measures Based on Genomic Distances
Authors: A. L. Barker, W. N. Martin
Venue:  (1999)

We define a class of genetic algorithms where, at each time step, two parents are selected to produce a child which then replaces one member of the population at the next time step. We consider the finite-population case. We define a general crossover and mutation operation, as well as a genomic distance between individuals. We require a specific property to hold for such operations and distance functions, and present examples of crossover operations, mutation operations, and distance functions which meet the requirements. We then define the sum over all pairwise population distances as a measure of the diversity of a population and consider the time evolution of the expected diversity of a population. We show that under uniform, independent selection of parents and the individual to be replaced the expected diversity is strictly decreasing. For this case we calculate an explicit formula for the diversity at each time step, based only on the initial population diversity. We then consider and discuss the case where independent, fitness-based selection is used and show that the expected diversity is strictly decreasing whenever the same probability function is used to select both the parents and the individual to be replaced. We qualitatively discuss conditions where expected diversity will increase rather than decrease with fitness-based selection. Finally, we discuss fitness measures based on a distance function.
CHITRA93: A System to Model Ensembles of Trace Data
Authors: Marc Abrams
Venue:  (1994)

CHITRA, a sanskrit word meaning a beautiful or pleasing picture, represents a new approach to understanding trace data generated by computer and communication systems. CHITRA can analyze any time series data, although its features are specifically tailored to trace data from computer and communication systems that we have studied over the years. Because a single trace file represents just a single observation may or may not be representative of the range of behavior that the system can manifest, CHITRA93 analyzes multiple trace files representing multiple observations. A collection of trace files is called an ensemble. CHITRA couples methods to visualize and statistically analyze ensembles, culminating in the construction of one or more models that fit the data in an ensemble. CHITRA addresses the potential state space explosion problem in a model by providing a set of transforms that aggregate or delete information from a trace file.
Multiresolution Geometric Algorithms Using Wavelets I: Representation for Parametric Curves and Surfaces
Authors: L. M. Reissell
Venue:  (1993)

We develop wavelet methods for the multiresolution representation of parametric curves and surfaces. To support the representation, we construct a new family of compactly supported symmetric biorthogonal wavelets with interpolating scaling functions. The wavelets in these biorthogonal pairs have properties better suited for curves and surfaces than many commonly used filters. We also give examples of the applications of the wavelet approach: these include the derivation of compact hierarchical curve and surface representations using modified wavelet compression, identifying smooth sections of surfaces and a subdivision-like intersection algorithm for discrete plane curves.
Feature selection in data mining
Authors: YongSeog Kim, W. Nick Street, Filippo Menczer
Venue: Data mining: opportunities and challenges (2003)

Feature subset selection is an important problem in knowledge discovery, not only for the insight gained from determining relevant modeling variables, but also for the improved understandability, scalability, and, possibly, accuracy of the resulting models. The purpose of this chapter is to provide a comprehensive analysis of feature selection via evolutionary search in supervised and unsupervised learning. To achieve this purpose, we first discuss a general framework for feature selection based on a new search algorithm, Evolutionary Local Selection Algorithm (ELSA). The search is formulated as a multi-objective optimization problem to examine the trade-off between the complexity of the generated solutions against their quality. ELSA considers multiple objectives efficiently while avoiding computationally expensive global comparison. We combine ELSA with Artificial Neural Networks (ANNs) and Expectation-Maximization (EM) algorithms for feature selection in supervised and unsupervised learning respectively. Further, we provide a new two-level evolutionary algorithm, Meta-Evolutionary Ensembles (MEE), where feature selection is used to promote the diversity among classifiers in the same ensemble.
COMPOSITE GEOMETRIC CONCEPTS AND POLYNOMIAL PREDICTABILITY
Authors: Philip M. Long, Manfred K. Warmuth
Venue:  (1990)

We study the predictability of geometric concepts, in particular those defined by boolean combinations of simple geometric objects. First, we give a negative result, showing that the problem of predicting the class of convex polytopes encoded by listing their vertices is prediction complete for P . Thus, an efficient solution to this prediction problem implies the existence of efficient solutions to all prediction problems whose associated evaluation problem is in P . Assuming the existence of a one-way function that is hard on iterates, there are such prediction problems which do not admit efficient solutions. Thus we show under minimalist cryptographic assumptions that the class of convex polytopes encoded by listing their vertices is not predictable. As a side effect, we show that determining membership in the convex hull of a given set of points is complete for P with respect to log space reductions. Next, we establish the predictability of the class consisting of unions of a fixed number of flats by reducing its prediction problem to that of the class of flats, which has previously been shown to be predictable. Finally, we given an Occam algorithm for predicting fixed finite unions of boxes. Both constructive results for flats and boxes hold if the dimension is variable.
EXPLICIT WINDOW ADAPTATION: A METHOD TO ENHANCE TCP PERFORMANCE
Authors: Lampros Kalampoukas, Anujan Varma, K. K. Ramakrishnan
Venue:  (1997)

We study the performance of TCP in an internetwork consisting of both rate-controlled and non-rate-controlled segments. A common example of such an environment occurs when the end systems are part of IP datagram networks interconnected by a rate-controlled segment, such as an ATM network using the ABR service. In the absence of congestive losses in either segment, TCP keeps increasing its window to its maximum size. Mismatch between the TCP window and the bandwidth-delay product of the network will result in accumulation of large queues and possibly buffer overflows in the devices at the edges of the rate-controlled segment, causing degraded throughput and unfairness. We develop an explicit feedback scheme, called Explicit Window Adaptation based on modifying the receiver''s advertised window in TCP acknowledgments returning to the source. The window size indicated to TCP is a function of the free buffer in the edge device. Results from simulations with a wide range of traffic scenarios show that this explicit window adaptation scheme can control the buffer occupancy efficiently at the edge device, and results in significant improvements in packet loss rate, fairness, and throughput over a packet discard policy such as Drop-from-Front or Random Early Detection.
A Theorem Prover for ASTRAL
Authors: Paul Z. Kolano
Venue:  (1998)

The ASTRAL real-time formal specification language has been encoded into the PVS theorem prover. A translator has been developed to completely translate any single-level ASTRAL specification into its corresponding PVS encoding. The semantics of the ASTRAL abstract machine have been revised and expanded for use with PVS. This paper describes the encoding and semantics and explains their use along with providing additional applications of the encoding.
An Assessment of SEES Based on Operational Experiences
Authors: Arthur James D., Groener Markus
Venue:  (1997)

During the Fall of 1995 a modified form of SEES (Software Engineering Evaluation System), denoted SEES, was defined and used in a study to examine the value added of Independent Verification and Validation. A follow-on study, and topic of this report, focuses on an assessment of SEES based on operational experiences gained from the 1995 study. The report partitions its findings relative to phases of the software development process.
An Isotach Network Simulator
Authors: Lance Hopenwasser
Venue:  (1998)

We have developed a simulator of Isotach systems which run on a Myrinet network. The simulator allows us to study the performance characteristics of the system and provides a means for experimenting with alternative implementations of Isotach networks. The rate at which tokens flow through the network determines the rate at which Isotach logical time progresses; therefore, token behavior is of keen interest. The simulator gathers performance data that is used to examine the behavior of tokens within the network under several different conditions. The simulator is also capable of obtaining similar data on barriers that make use of the Isotach network. These barriers are of interest, because they can be used to establish network-wide checkpoints in addition to other application-level uses. The simulator can provide data on characteristics of the network that most affect barrier completion time. Furthermore, the simulator can be used to compare the Isotach barrier algorithm to a simple centralized non-Isotach barrier algorithm. We present some of the issues that influenced the design of the simulator. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Self-Organizing Switchbox Routing on an Adaptive Resistor Grid
Authors: Allen L. Barker
Venue:  (1997)

The switchbox routing problem arises in the fabrication of computer chips, and is representative of a general class of routing problems. We describe a self-organizing algorithm for solving certain instances of the switchbox routing problem. The method is based on path formation via a positive feedback process, with competitive interactions. We define such a process on a grid of adaptive, variable resistors and simulate its dynamics. The method is applied to several problem instances.
DETECTING UNEXPECTED DATA VALUES IN OPTIMIZED CODE
Authors: Max Copperman, Charles E. McDowell
Venue:  (1990)

Optimizing compilers produce code that impedes source-level debugging. After optimization, the correspondence between a program''s source code and object code is not straightforward. An important problem for a source-level debugger of optimized programs is to be able to determine when, because of optimizations, the value of a variable does not correspond to what the user expects. The paper describes a solution to this problem. The solution uses reaching sets to determine when the definitions of a variable that reach a breakpoint location in an optimized program are not the definitions that would have reached in the unoptimized program.
Speech Processing using Artificial Neural Networks
Authors: Roberto Togneri, Mike Alder, Yianni Attikiouzel
Venue:  (1990)

A three layer perceptron network is used to classify the /i/ sound using isolated words from different speakers. A classification accuracy of 97% has been achieved. A map of phonemes is used to trace trajectories of utterances using the self-organising neural network. A crinkle factor is proposed which allows using the self-organising map to determine the inherent dimensionality of a set of points. By this technique speech data has been shown to possess an inherent dimensionality of at least four. A projection of the map and the speech data shows how the self-organising map fits the speech space.
Controlling Fluid Flow Simulation
Authors: William F. Gates, Alain Fournier
Venue:  (2002)

Simulating fluid dynamics can be a powerful approach to animating liquids and gases, but it is often difficult to ``direct'''' the simulation to ``perform'''' as desired. We introduce a simple yet powerful technique of controlling incompressible flow simulation for computer animation purposes that works for any simulation method using a projection scheme for numerically solving the Navier-Stokes equations. In our technique, an abstract vector field representing the desired influence over the simulated flow is modelled using simple primitives. This technique allows an arbitrarily degree of control over the simulated flow at every point while still conserving mass, momentum, and energy.