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|---|---|---|---|---|
2,194 | 5 | Title: Minimizing Register Requirements under Resource-Constrained Rate-Optimal Software Pipelining
Abstract: In this paper we address the following software pipelin-ing problem: given a loop and a machine architecture with a fixed number of processor resources (e.g. function units), how can one construct a software-pipelined schedule which runs on the given architecture at the maximum possible iteration rate (a la rate-optimal) while minimizing the number of registers? The main contributions of this paper are: * First, we demonstrate that such problem can be described by a simple mathematical formulation with precise optimization objectives under periodic linear scheduling framework. The mathematical formulation provides a clear picture which permits one to visualize the overall solution space (for rate-optimal schedules) under different sets of con straints. * Secondly, we show that a precise mathematical formulation and its solution does make a significant performance difference! We evaluated the performance of our method against three other leading contemporary heuristic methods: Huff 's Slack Scheduling [9], Wang, Eisenbeis, Jourdan and Su's FRLC [23], and Gasperoni and Schwiegelshohn's modified list scheduling [6]. Experimental results show that the method described in this paper performed significantly better than these methods. | [
1955,
2149,
2188,
2189,
2190
] | Validation |
2,195 | 5 | Title: LEARNING FOR DECISION MAKING: The FRD Approach and a Comparative Study Machine Learning and Inference Laboratory
Abstract: This paper concerns the issue of what is the best form for learning, representing and using knowledge for decision making. The proposed answer is that such knowledge should be learned and represented in a declarative form. When needed for decision making, it should be efficiently transferred to a procedural form that is tailored to the specific decision making situation. Such an approach combines advantages of the declarative representation, which facilitates learning and incremental knowledge modification, and the procedural representation, which facilitates the use of knowledge for decision making. This approach also allows one to determine decision structures that may avoid attributes that unavailable or difficult to measure in any given situation. Experimental investigations of the system, FRD-1, have demonstrated that decision structures obtained via the declarative route often have not only higher predictive accuracy but are also are simpler than those learned directly from facts. | [
286,
378,
1963
] | Test |
2,196 | 1 | Title: Effects of Occam's Razor in Evolving Sigma-Pi Neural Nets
Abstract: Several evolutionary algorithms make use of hierarchical representations of variable size rather than linear strings of fixed length. Variable complexity of the structures provides an additional representational power which may widen the application domain of evolutionary algorithms. The price for this is, however, that the search space is open-ended and solutions may grow to arbitrarily large size. In this paper we study the effects of structural complexity of the solutions on their generalization performance by analyzing the fitness landscape of sigma-pi neural networks. The analysis suggests that smaller networks achieve, on average, better generalization accuracy than larger ones, thus confirming the usefulness of Occam's razor. A simple method for implementing the Occam's razor principle is described and shown to be effective in improv ing the generalization accuracy without limiting their learning capacity. | [
163,
380,
938,
2267
] | Train |
2,197 | 6 | Title: MLC Tutorial A Machine Learning library of C classes.
Abstract: Several evolutionary algorithms make use of hierarchical representations of variable size rather than linear strings of fixed length. Variable complexity of the structures provides an additional representational power which may widen the application domain of evolutionary algorithms. The price for this is, however, that the search space is open-ended and solutions may grow to arbitrarily large size. In this paper we study the effects of structural complexity of the solutions on their generalization performance by analyzing the fitness landscape of sigma-pi neural networks. The analysis suggests that smaller networks achieve, on average, better generalization accuracy than larger ones, thus confirming the usefulness of Occam's razor. A simple method for implementing the Occam's razor principle is described and shown to be effective in improv ing the generalization accuracy without limiting their learning capacity. | [
430,
2342
] | Test |
2,198 | 6 | Title: An Incremental Interactive Algorithm for Regular Grammar Inference
Abstract: We present provably correct interactive algorithms for learning regular grammars from positive examples and membership queries. A structurally complete set of strings from a language L(G) corresponding to a target regular grammar G implicitly specifies a lattice of finite state automata (FSA) which contains a FSA M G corresponding to G. The lattice is compactly represented as a version-space and M G is identified by searching the version-space using membership queries. We explore the problem of regular grammar inference in a setting where positive examples are provided intermittently. We provide an incremental version of the algorithm along with a set of sufficient conditions for its convergence. | [
1560,
2537,
2695
] | Validation |
2,199 | 1 | Title: Position Paper, Workshop on Evolutionary Computation with Variable Size Representation, ICGA, Fitness Causes Bloat in
Abstract: We argue based upon the numbers of representations of given length, that increase in representation length is inherent in using a fixed evaluation function with a discrete but variable length representation. Two examples of this are analysed, including the use of Price's Theorem. Both examples confirm the tendency for solutions to grow in size is caused by fitness based selection. | [
1184,
1784,
2133
] | Train |
2,200 | 1 | Title: Adaptation in constant utility non-stationary environments
Abstract: Environments that vary over time present a fundamental problem to adaptive systems. Although in the worst case there is no hope of effective adaptation, some forms environmental variability do provide adaptive opportunities. We consider a broad class of non-stationary environments, those which combine a variable result function with an invariant utility function, and demonstrate via simulation that an adaptive strategy employing both evolution and learning can tolerate a much higher rate of environmental variation than an evolution-only strategy. We suggest that in many cases where stability has previously been assumed, the constant utility non-stationary environment may in fact be a more powerful viewpoint. | [
163,
1797,
1969,
2703
] | Train |
2,201 | 2 | Title: Neural competitive maps for reactive and adaptive navigation
Abstract: We have recently introduced a neural network for reactive obstacle avoidance based on a model of classical and operant conditioning. In this article we describe the success of this model when implemented on two real autonomous robots. Our results show the promise of self-organizing neural networks in the domain of intelligent robotics. | [
2233
] | Train |
2,202 | 1 | Title: An Evolutionary Approach to Combinatorial Optimization Problems
Abstract: The paper reports on the application of genetic algorithms, probabilistic search algorithms based on the model of organic evolution, to NP-complete combinatorial optimization problems. In particular, the subset sum, maximum cut, and minimum tardy task problems are considered. Except for the fitness function, no problem-specific changes of the genetic algorithm are required in order to achieve results of high quality even for the problem instances of size 100 used in the paper. For constrained problems, such as the subset sum and the minimum tardy task, the constraints are taken into account by incorporating a graded penalty term into the fitness function. Even for large instances of these highly multimodal optimization problems, an iterated application of the genetic algorithm is observed to find the global optimum within a number of runs. As the genetic algorithm samples only a tiny fraction of the search space, these results are quite encouraging. | [
163,
1303,
1571,
1980,
2638
] | Train |
2,203 | 2 | Title: CuPit-2: Portable and Efficient High-Level Parallel Programming of Neural Networks for the Systems Analysis Modelling
Abstract: CuPit-2 is a special-purpose programming language designed for expressing dynamic neural network learning algorithms. It provides most of the flexibility of general-purpose languages such as C or C ++ , but is more expressive. It allows writing much clearer and more elegant programs, in particular for algorithms that change the network topology dynamically (constructive algorithms, pruning algorithms). In contrast to other languages, CuPit-2 programs can be compiled into efficient code for parallel machines without any changes in the source program, thus providing an easy start for using parallel platforms. This article analyzes the circumstances under which the CuPit-2 approach is the most useful one, presents a description of most language constructs and reports performance results for CuPit-2 on symmetric multiprocessors (SMPs). It concludes that in many cases CuPit-2 is a good basis for neural learning algorithm research on small-scale parallel machines. | [
881,
1411,
2397,
2405
] | Train |
2,204 | 1 | Title: University of Nevada Reno Design Strategies for Evolutionary Robotics
Abstract: CuPit-2 is a special-purpose programming language designed for expressing dynamic neural network learning algorithms. It provides most of the flexibility of general-purpose languages such as C or C ++ , but is more expressive. It allows writing much clearer and more elegant programs, in particular for algorithms that change the network topology dynamically (constructive algorithms, pruning algorithms). In contrast to other languages, CuPit-2 programs can be compiled into efficient code for parallel machines without any changes in the source program, thus providing an easy start for using parallel platforms. This article analyzes the circumstances under which the CuPit-2 approach is the most useful one, presents a description of most language constructs and reports performance results for CuPit-2 on symmetric multiprocessors (SMPs). It concludes that in many cases CuPit-2 is a good basis for neural learning algorithm research on small-scale parallel machines. | [
163,
636,
846,
2173
] | Validation |
2,205 | 1 | Title: A Genetic Local Search Approach to the Quadratic Assignment Problem
Abstract: Augmenting genetic algorithms with local search heuristics is a promising approach to the solution of combinatorial optimization problems. In this paper, a genetic local search approach to the quadratic assignment problem (QAP) is presented. New genetic operators for realizing the approach are described, and its performance is tested on various QAP instances containing between 30 and 256 facilities/locations. The results indicate that the proposed algorithm is able to arrive at high quality solutions in a relatively short time limit: for the largest publicly known prob lem instance, a new best solution could be found. | [
1799
] | Validation |
2,206 | 1 | Title: Why Ants are Hard genetic programming, simulated annealing and hill climbing performance is shown not
Abstract: The problem of programming an artificial ant to follow the Santa Fe trail is used as an example program search space. Analysis of shorter solutions shows they have many of the characteristics often ascribed to manually coded programs. Enumeration of a small fraction of the total search space and random sampling characterise it as rugged with many multiple plateaus split by deep valleys and many local and global optima. This suggests it is difficult for hill climbing algorithms. Analysis of the program search space in terms of fixed length schema suggests it is highly deceptive and that for the simplest solutions large building blocks must be assembled before they have above average fitness. In some cases we show solutions cannot be assembled using a fixed representation from small building blocks of above average fitness. These suggest the Ant problem is difficult for Genetic Algorithms. Random sampling of the program search space suggests on average the density of global optima changes only slowly with program size but the density of neutral networks linking points of the same fitness grows approximately linearly with program length. This is part of the cause of bloat. | [
1911,
1925,
1984,
2133,
2175,
2261,
2379
] | Train |
2,207 | 4 | Title: Machine Learning Research: Four Current Directions
Abstract: Machine Learning research has been making great progress is many directions. This article summarizes four of these directions and discusses some current open problems. The four directions are (a) improving classification accuracy by learning ensembles of classifiers, (b) methods for scaling up supervised learning algorithms, (c) reinforcement learning, and (d) learning complex stochastic models. | [
79,
1786
] | Train |
2,208 | 3 | Title: Extensions of Fill's algorithm for perfect simulation
Abstract: Fill's algorithm for perfect simulation for attractive finite state space models, unbiased for user impatience, is presented in terms of stochastic recursive sequences and extended in two ways. Repulsive discrete Markov random fields with two coding sets like the auto-Poisson distribution on a lattice with 4-neighbourhood can be treated as monotone systems if a particular partial ordering and quasi-maximal and quasi-minimal states are used. Fill's algorithm then applies directly. Combining Fill's rejection sampling with sandwiching leads to a version of the algorithm, which works for general discrete conditionally specified repulsive models. Extensions to other types of models are briefly discussed. | [
126,
1761,
2234,
2235,
2313
] | Train |
2,209 | 4 | Title: PAC Adaptive Control of Linear Systems
Abstract: We consider a special case of reinforcement learning where the environment can be described by a linear system. The states of the environment and the actions the agent can perform are represented by real vectors and the system dynamic is given by a linear equation with a stochastic component. The problem is equivalent to the so-called linear quadratic regulator problem studied in the optimal and adaptive control literature. We propose a learning algorithm for that problem and analyze it in a PAC learning framework. Unlike the algorithms in the adaptive control literature, our algorithm actively explores the environment to learn an accurate model of the system faster. We show that the control law produced by our algorithm has, with high probability, a value that is close to that of an optimal policy relative to the magnitude of the initial state of the system. The time taken by the algorithm is polynomial in the dimension n of the state-space and in the dimension r of the action-space when the ratio n=r is a constant. | [
2689
] | Train |
2,210 | 6 | Title: An Empirical Analysis of the Benefit of Decision Tree Size Biases as a Function of
Abstract: The results reported here empirically show the benefit of decision tree size biases as a function of concept distribution. First, it is shown how concept distribution complexity (the number of internal nodes in the smallest decision tree consistent with the example space) affects the benefit of minimum size and maximum size decision tree biases. Second, a policy is described that defines what a learner should do given knowledge of the complexity of the distribution of concepts. Third, explanations for why the distribution of concepts seen in practice is amenable to the minimum size decision tree bias are given and evaluated empirically. | [
1808
] | Train |
2,211 | 1 | Title: Collective Memory Search 1 Collective Memory Search: Exploiting an Information Center for Exploration
Abstract: The results reported here empirically show the benefit of decision tree size biases as a function of concept distribution. First, it is shown how concept distribution complexity (the number of internal nodes in the smallest decision tree consistent with the example space) affects the benefit of minimum size and maximum size decision tree biases. Second, a policy is described that defines what a learner should do given knowledge of the complexity of the distribution of concepts. Third, explanations for why the distribution of concepts seen in practice is amenable to the minimum size decision tree bias are given and evaluated empirically. | [
854,
1232,
1971
] | Validation |
2,212 | 2 | Title: ANALYSIS OF SOUND TEXTURES IN MUSICAL AND MACHINE SOUNDS BY MEANS OF HIGHER ORDER STATISTICAL FEATURES.
Abstract: In this paper we describe a sound classification method, which seems to be applicable to a broad domain of stationary, non-musical sounds, such as machine noises and other man made non periodic sounds. The method is based on matching higher order spectra (HOS) of the acoustic signals and it generalizes our earlier results on classification of sustained musical sounds by higher order statistics. An efficient "decorrelated matched filter" implemetation is presented. The results show good sound classification statistics and a comparison to spectral matching methods is also discussed. | [
2121
] | Validation |
2,213 | 5 | Title: Generating Declarative Language Bias for Top-Down ILP Algorithms
Abstract: Many of today's algorithms for Inductive Logic Programming (ILP) put a heavy burden and responsibility on the user, because their declarative bias have to be defined in a rather low-level fashion. To address this issue, we developed a method for generating declarative language bias for top-down ILP systems from high-level declarations. The key feature of our approach is the distinction between a user level and an expert level of language bias declarations. The expert provides abstract meta-declarations, and the user declares the relationship between the meta-level and the given database to obtain a low-level declarative language bias. The suggested languages allow for compact and abstract specifications of the declarative language bias for top-down ILP systems using schemata. We verified several properties of the translation algorithm that generates schemata, and applied it successfully to a few chemical domains. As a consequence, we propose to use a two-level approach to generate declarative language bias. | [
1259,
2126,
2253,
2290,
2539
] | Train |
2,214 | 2 | Title: Behavior Near Zero of the Distribution of GCV Smoothing Parameter Estimates 1
Abstract: Many of today's algorithms for Inductive Logic Programming (ILP) put a heavy burden and responsibility on the user, because their declarative bias have to be defined in a rather low-level fashion. To address this issue, we developed a method for generating declarative language bias for top-down ILP systems from high-level declarations. The key feature of our approach is the distinction between a user level and an expert level of language bias declarations. The expert provides abstract meta-declarations, and the user declares the relationship between the meta-level and the given database to obtain a low-level declarative language bias. The suggested languages allow for compact and abstract specifications of the declarative language bias for top-down ILP systems using schemata. We verified several properties of the translation algorithm that generates schemata, and applied it successfully to a few chemical domains. As a consequence, we propose to use a two-level approach to generate declarative language bias. | [
420,
2223
] | Test |
2,215 | 0 | Title: Learning Approximate Control Rules Of High Utility
Abstract: One of the difficult problems in the area of explanation based learning is the utility problem; learning too many rules of low utility can lead to swamping, or degradation of performance. This paper introduces two new techniques for improving the utility of learned rules. The first technique is to combine EBL with inductive learning techniques to learn a better set of control rules; the second technique is to use these inductive techniques to learn approximate control rules. The two techniques are synthesized in an algorithm called approximating abductive explanation based learning (AxA-EBL). AxA-EBL is shown to improve substantially over standard EBL in several domains. | [
344,
551,
675,
1877,
2057,
2650
] | Train |
2,216 | 1 | Title: Hybridized Crossover-Based Search Techniques for Program Discovery
Abstract: In this paper we address the problem of program discovery as defined by Genetic Programming [10]. We have two major results: First, by combining a hierarchical crossover operator with two traditional single point search algorithms: Simulated Annealing and Stochastic Iterated Hill Climbing, we have solved some problems with fewer fitness evaluations and a greater probability of a success than Genetic Programming. Second, we have managed to enhance Genetic Programming by hybridizing it with the simple scheme of hill climbing from a few individuals, at a fixed interval of generations. The new hill climbing component has two options for generating candidate solutions: mutation or crossover. When it uses crossover, mates are either randomly created, randomly drawn from the population at large, or drawn from a pool of fittest individuals. | [
2361,
2688,
2705
] | Train |
2,217 | 5 | Title: Application of Clausal Discovery to Temporal Databases
Abstract: Most of KDD applications consider databases as static objects, and however many databases are inherently temporal, i.e., they store the evolution of each object with the passage of time. Thus, regularities about the dynamics of these databases cannot be discovered as the current state might depend in some way on the previous states. To this end, a pre-processing of data is needed aimed at extracting relationships intimately connected to the temporal nature of data that will be make available to the discovery algorithm. The predicate logic language of ILP methods together with the recent advances as to ef ficiency makes them adequate for this task. | [
1007,
2282
] | Test |
2,218 | 2 | Title: L 0 |The First Four Years Abstract A summary of the progress and plans of
Abstract: Most of KDD applications consider databases as static objects, and however many databases are inherently temporal, i.e., they store the evolution of each object with the passage of time. Thus, regularities about the dynamics of these databases cannot be discovered as the current state might depend in some way on the previous states. To this end, a pre-processing of data is needed aimed at extracting relationships intimately connected to the temporal nature of data that will be make available to the discovery algorithm. The predicate logic language of ILP methods together with the recent advances as to ef ficiency makes them adequate for this task. | [
2021,
2049,
2337
] | Train |
2,219 | 3 | Title: Exponential Convergence of Langevin Diffusions and Their Discrete Approximations
Abstract: In this paper we consider a continous time method of approximating a given distribution using the Langevin diffusion dL t = dW t + 1 2 r log (L t )dt: We find conditions under which this diffusion converges exponentially quickly to or does not: in one dimension, these are essentially that for distributions with exponential tails of the form (x) / exp(fljxj fi ), 0 < fi < 1, exponential convergence occurs if and only if fi 1. We then consider conditions under which the discrete approximations to the diffusion converge. We first show that even when the diffusion itself converges, naive discretisations need not do so. We then consider a "Metropolis-adjusted" version of the algorithm, and find conditions under which this also converges at an exponential rate: perhaps surprisingly, even the Metropolised version need not converge exponentially fast even if the diffusion does. We briefly discuss a truncated form of the algorithm which, in practice, should avoid the difficulties of the other forms. | [
1977,
2008,
2022,
2153
] | Validation |
2,220 | 1 | Title: The Automatic Programming of Agents that Learn Mental Models and Create Simple Plans of Action
Abstract: An essential component of an intelligent agent is the ability to notice, encode, store, and utilize information about its environment. Traditional approaches to program induction have focused on evolving functional or reactive programs. This paper presents MAPMAKER, an approach to the automatic generation of agents that discover information about their environment, encode this information for later use, and create simple plans utilizing the stored mental models. In this approach, agents are multipart computer programs that communicate through a shared memory. Both the programs and the representation scheme are evolved using genetic programming. An illustrative problem of 'gold' collection is used to demonstrate the approach in which one part of a program makes a map of the world and stores it in memory, and the other part uses this map to find the gold The results indicate that the approach can evolve programs that store simple representations of their environments and use these representations to produce simple plans. 1. Introduction | [
129,
290,
1409,
1940,
1950,
1958,
2139,
2226,
2252,
2478,
2563,
2600
] | Test |
2,221 | 3 | Title: Reasoning about Time and Probability
Abstract: An essential component of an intelligent agent is the ability to notice, encode, store, and utilize information about its environment. Traditional approaches to program induction have focused on evolving functional or reactive programs. This paper presents MAPMAKER, an approach to the automatic generation of agents that discover information about their environment, encode this information for later use, and create simple plans utilizing the stored mental models. In this approach, agents are multipart computer programs that communicate through a shared memory. Both the programs and the representation scheme are evolved using genetic programming. An illustrative problem of 'gold' collection is used to demonstrate the approach in which one part of a program makes a map of the world and stores it in memory, and the other part uses this map to find the gold The results indicate that the approach can evolve programs that store simple representations of their environments and use these representations to produce simple plans. 1. Introduction | [
566,
1459,
1527,
1757,
2404
] | Test |
2,222 | 4 | Title: Multi-Time Models for Reinforcement Learning
Abstract: Reinforcement learning can be used not only to predict rewards, but also to predict states, i.e. to learn a model of the world's dynamics. Models can be defined at different levels of temporal abstraction. Multi-time models are models that focus on predicting what will happen, rather than when a certain event will take place. Based on multi-time models, we can define abstract actions, which enable planning (presumably in a more efficient way) at various levels of abstraction. | [
1954,
2150
] | Test |
2,223 | 2 | Title: Smoothing Spline Models With Correlated Random Errors 1
Abstract: Reinforcement learning can be used not only to predict rewards, but also to predict states, i.e. to learn a model of the world's dynamics. Models can be defined at different levels of temporal abstraction. Multi-time models are models that focus on predicting what will happen, rather than when a certain event will take place. Based on multi-time models, we can define abstract actions, which enable planning (presumably in a more efficient way) at various levels of abstraction. | [
190,
510,
519,
2214
] | Train |
2,224 | 2 | Title: Design of Optimization Criteria for Multiple Sequence Alignment
Abstract: DIMACS Technical Report 96-53 January 1997 | [
1827
] | Train |
2,225 | 6 | Title: Error-Correcting Output Coding Corrects Bias and Variance
Abstract: Previous research has shown that a technique called error-correcting output coding (ECOC) can dramatically improve the classification accuracy of supervised learning algorithms that learn to classify data points into one of k 2 classes. This paper presents an investigation of why the ECOC technique works, particularly when employed with decision-tree learning algorithms. It shows that the ECOC method| like any form of voting or committee|can reduce the variance of the learning algorithm. Furthermore|unlike methods that simply combine multiple runs of the same learning algorithm|ECOC can correct for errors caused by the bias of the learning algorithm. Experiments show that this bias correction ability relies on the non-local be havior of C4.5. | [
256,
1608,
1732,
2423
] | Validation |
2,226 | 1 | Title: Simultaneous Evolution of Programs and their Control Structures Simultaneous Evolution of Programs and their Control
Abstract: Previous research has shown that a technique called error-correcting output coding (ECOC) can dramatically improve the classification accuracy of supervised learning algorithms that learn to classify data points into one of k 2 classes. This paper presents an investigation of why the ECOC technique works, particularly when employed with decision-tree learning algorithms. It shows that the ECOC method| like any form of voting or committee|can reduce the variance of the learning algorithm. Furthermore|unlike methods that simply combine multiple runs of the same learning algorithm|ECOC can correct for errors caused by the bias of the learning algorithm. Experiments show that this bias correction ability relies on the non-local be havior of C4.5. | [
1950,
1958,
2139,
2220,
2478
] | Validation |
2,227 | 2 | Title: The EM Algorithm for Mixtures of Factor Analyzers
Abstract: Technical Report CRG-TR-96-1 May 21, 1996 (revised Feb 27, 1997) Abstract Factor analysis, a statistical method for modeling the covariance structure of high dimensional data using a small number of latent variables, can be extended by allowing different local factor models in different regions of the input space. This results in a model which concurrently performs clustering and dimensionality reduction, and can be thought of as a reduced dimension mixture of Gaussians. We present an exact Expectation-Maximization algorithm for fitting the parameters of this mixture of factor analyzers. | [
667,
1923,
1974,
2072,
2390
] | Train |
2,228 | 2 | Title: Modeling dynamic receptive field changes in primary visual cortex using inhibitory learning
Abstract: The position, size, and shape of the visual receptive field (RF) of some primary visual cortical neurons change dynamically, in response to artificial scotoma conditioning in cats (Pettet & Gilbert, 1992) and to retinal lesions in cats and monkeys (Darian-Smith & Gilbert, 1995). The "EXIN" learning rules (Marshall, 1995) are used to model dynamic RF changes. The EXIN model is compared with an adaptation model (Xing & Gerstein, 1994) and the LISSOM model (Sirosh & Miikkulainen, 1994; Sirosh et al., 1996). To emphasize the role of the lateral inhibitory learning rules, the EXIN and the LISSOM simulations were done with only lateral inhibitory learning. During scotoma conditioning, the EXIN model without feedforward learning produces centrifugal expansion of RFs initially inside the scotoma region, accompanied by increased responsiveness, without changes in spontaneous activation. The EXIN model without feedforward learning is more consistent with the neurophysiological data than are the adaptation model and the LISSOM model. The comparison between the EXIN and the LISSOM models suggests experiments to determine the role of feedforward excitatory and lateral inhibitory learning in producing dynamic RF changes during scotoma conditioning. | [
127,
1093,
1094,
2068,
2085
] | Train |
2,229 | 5 | Title: Bottom-up induction of logic programs with more than one recursive clause
Abstract: In this paper we present a bottom-up algorithm called MRI to induce logic programs from their examples. This method can induce programs with a base clause and more than one recursive clause from a very small number of examples. MRI is based on the analysis of saturations of examples. It first generates a path structure, which is an expression of a stream of values processed by predicates. The concept of path structure was originally introduced by Identam-Almquist and used in TIM [ Idestam-Almquist, 1996 ] . In this paper, we introduce the concepts of extension and difference of path structure. Recursive clauses can be expressed as a difference between a path structure and its extension. The paper presents the algorithm and shows experimental results obtained by the method. | [
344,
1428,
2663
] | Train |
2,230 | 2 | Title: In Advances in Neural Information Processing Systems 8 Gaussian Processes for Regression
Abstract: The Bayesian analysis of neural networks is difficult because a simple prior over weights implies a complex prior distribution over functions. In this paper we investigate the use of Gaussian process priors over functions, which permit the predictive Bayesian analysis for fixed values of hyperparameters to be carried out exactly using matrix operations. Two methods, using optimization and averaging (via Hybrid Monte Carlo) over hyperparameters have been tested on a number of challenging problems and have produced excellent results. | [
157,
608,
611,
2095
] | Train |
2,231 | 0 | Title: Explaining Anomalies as a Basis for Knowledge Base Refinement
Abstract: Explanations play a key role in operationalization-based anomaly detection techniques. In this paper we show that their role is not limited to anomaly detection; they can also be used for guiding automated knowledge base refinement. We introduce a refinement procedure which takes: (i) a small number of refinement rules (rather than test cases), and (ii) explanations constructed in an attempt to reveal the cause (or causes) for inconsistencies detected during the verification process, and returns rule revisions aiming to recover the consistency of the KB-theory. Inconsistencies caused by more than one anomaly are handled at the same time, which improves the efficiency of the refinement process. | [
136,
2635
] | Train |
2,232 | 1 | Title: Facing The Facts: Necessary Requirements For The Artificial Evolution of Complex Behaviour
Abstract: This paper sets out a conceptual framework for the open-ended artificial evolution of complex behaviour in autonomous agents. If recurrent dynamical neural networks (or similar) are used as phenotypes, then a Genetic Algorithm that employs variable length genotypes, such as Inman Harvey's SAGA, is capable of evolving arbitrary levels of be-havioural complexity. Furthermore, with simple restrictions on the encoding scheme that governs how genotypes develop into phenotypes, it may be guaranteed that if an increase in fitness requires an increase in be-havioural complexity, then it will evolve. In order for this process to be practicable as a design alternative, however, the time periods involved must be acceptable. The final part of this paper looks at general ways in which the encoding scheme may be modified to speed up the process. Experiments are reported in which different categories of scheme were tested against each other, and conclusions are offered as to the most promising type of encoding scheme for a vi able open-ended Evolutionary Robotics. | [
163,
411,
2058
] | Validation |
2,233 | 2 | Title: An unsupervised neural network for low-level control of a wheeled mobile robot: noise resistance, stability,
Abstract: We have recently introduced a neural network mobile robot controller (NETMORC) that autonomously learns the forward and inverse odometry of a differential drive robot through an unsupervised learning-by-doing cycle. After an initial learning phase, the controller can move the robot to an arbitrary stationary or moving target while compensating for noise and other forms of disturbance, such as wheel slippage or changes in the robot's plant. In addition, the forward odometric map allows the robot to reach targets in the absence of sensory feedback. The controller is also able to adapt in response to long-term changes in the robot's plant, such as a change in the radius of the wheels. In this article we review the NETMORC architecture and describe its simplified algorithmic implementation, we present new, quantitative results on NETMORC's performance and adaptability under noise-free and noisy conditions, we compare NETMORC's performance on a trajectory-following task with the performance of an alternative controller, and we describe preliminary results on the hardware implementation of NETMORC with the mobile robot ROBUTER. | [
636,
703,
2201
] | Validation |
2,234 | 3 | Title: Perfect Sampling of Harris Recurrent Markov Chains
Abstract: We develop an algorithm for simulating "perfect" random samples from the invariant measure of a Harris recurrent Markov chain. The method uses backward coupling of embedded regeneration times, and works most effectively for finite chains and for stochastically monotone chains even on continuous spaces, where paths may be sandwiched below "upper" and "lower" processes. Examples show that more naive approaches to constructing such bounding processes may be considerably biased, but that the algorithm can be simplified in certain cases to make it easier to run. We give explicit analytic bounds on the backward coupling times in the stochastically monotone case. | [
2208
] | Train |
2,235 | 3 | Title: EXACT SIMULATION USING MARKOV CHAINS
Abstract: This reports gives a review of the new exact simulation algorithms using Markov chains. The first part covers the discrete case. We consider two different algorithms, Propp and Wilsons coupling from the past (CFTP) technique and Fills rejection sampler. The algorithms are tested on the Ising model, with and without an external field. The second part covers continuous state spaces. We present several algorithms developed by Murdoch and Green, all based on coupling from the past. We discuss the applicability of these methods on a Bayesian analysis problem of surgical failure rates. | [
2208
] | Train |
2,236 | 2 | Title: Robust Convergence of Two-Stage Nonlinear Algorithms for Identification in H 1
Abstract: | [
2262,
2435,
2542
] | Train |
2,237 | 1 | Title: Specialization under Social Conditions in Shared Environments
Abstract: Specialist and generalist behaviors in populations of artificial neural networks are studied. A genetic algorithm is used to simulate evolution processes, and thereby to develop neural network control systems that exhibit specialist or generalist behaviors according to the fitness formula. With evolvable fitness formulae the evaluation measure is let free to evolve, and we obtain a co-evolution of the expressed behavior and the individual evolvable fitness formula. The use of evolvable fitness formulae lets us work in a dynamic fitness landscape, opposed to most work, that traditionally applies to static fitness landscapes, only. The role of competition in specialization is studied by letting the individuals live under social conditions in the same, shared environment and directly compete with each other. We find, that competition can act to provide population diversification in populations of organisms with individual evolvable fitness formulae. | [
2170,
2274
] | Test |
2,238 | 1 | Title: Where Does the Good Stuff Go, and Why? How contextual semantics influences program structure in
Abstract: Using deliberately designed primitive sets, we investigate the relationship between context-based expression mechanisms and the size, height and density of genetic program trees during the evolutionary process. We show that contextual semantics influence the composition, location and flows of operative code in a program. In detail we analyze these dynamics and discuss the impact of our findings on micro-level descriptions of genetic programming. | [
2271
] | Test |
2,239 | 2 | Title: Predicting Conditional Probability Distributions: A Connectionist Approach
Abstract: Most traditional prediction techniques deliver the mean of the probability distribution (a single point). For multimodal processes, instead of predicting the mean of the probability distribution, it is important to predict the full distribution. This article presents a new connectionist method to predict the conditional probability distribution in response to an input. The main idea is to transform the problem from a regression to a classification problem. The conditional probability distribution network can perform both direct predictions and iterated predictions, a task which is specific for time series problems. We compare our method to fuzzy logic and discuss important differences, and also demonstrate the architecture on two time series. The first is the benchmark laser series used in the Santa Fe competition, a deterministic chaotic system. The second is a time series from a Markov process which exhibits structure on two time scales. The network produces multimodal predictions for this series. We compare the predictions of the network with a nearest-neighbor predictor and find that the conditional probability network is more than twice as likely a model. | [
587,
1366,
2413,
2414,
2507,
2513
] | Train |
2,240 | 5 | Title: Stable ILP Exploring the Added Expressivity of Negation in the Background Knowledge
Abstract: We present stable ILP, a cross-disciplinary concept straddling machine learning and nonmonotonic reasoning. Stable models give meaning to logic programs containing negative assertions. In stable ILP, we employ stable models to represent the current state specified by (possibly) negative EDB and IDB rules. The state then serves as the background knowledge for a top-down ILP learner. We present a framework and implementation (system INDED) of one realization of stable ILP. | [
2466
] | Validation |
2,241 | 3 | Title: On Decision-Theoretic Foundations for Defaults
Abstract: In recent years, considerable effort has gone into understanding default reasoning. Most of this effort concentrated on the question of entailment, i.e., what conclusions are warranted by a knowledge-base of defaults. Surprisingly, few works formally examine the general role of defaults. We argue that an examination of this role is necessary in order to understand defaults, and suggest a concrete role for defaults: Defaults simplify our decision-making process, allowing us to make fast, approximately optimal decisions by ignoring certain possible states. In order to formalize this approach, we examine decision making in the framework of decision theory. We use probability and utility to measure the impact of possible states on the decision-making process. We accept a default if it ignores states with small impact according to our measure. We motivate our choice of measures and show that the resulting formalization of defaults satisfies desired properties of defaults, namely cumulative reasoning. Finally, we compare our approach with Poole's decision-theoretic defaults, and show how both can be combined to form an attractive framework for reasoning about decisions. We make numerous assumptions each day: the car will start, the road will not be blocked, there will be heavy traffic at 5pm, etc. Many of these assumptions are defeasible; we are willing to retract them given sufficient evidence. Humans naturally state defaults and draw conclusions from default information. Hence, defaults seem to play an important part in common-sense reasoning. To use such statements, however, we need a formal understanding of what defaults represent and what conclusions they admit. The problem of default entailment|roughly, what conclusions we should draw from a knowledge-base of defaults|has attracted a great deal of attention. Many researchers attempt to find "context-free" patterns of default reasoning (e.g., [ Kraus et al., 1990 ] ). As this research shows, much can be done in this approach. We claim, however, that the utility of this approach is limited; to gain a better understanding of defaults, we need to understand in what situations we should be willing to state a default. Our main thesis is that an investigation of defaults should elaborate their role in the behavior of the reasoning agent. This role should allow us to examine when a default is appropriate in terms of its implications on the agent's overall performance. In this paper, we suggest a particular role for defaults and show how this role allows us to provide a semantics for defaults. Of course, we do not claim that this is the only role defaults can play. In many applications, the end result of reasoning is a choice of actions. Usually, this choice is not optimal; there is too much uncertainty about the state of the world and the effects of actions to allow for an examination of all possibilities. We suggest that one role of defaults lies in simplifying our decision-making process by stating assumptions that reduce the space of examined possibilities. More precisely, we suggest that a default ' ! is a license to ignore : situations when our knowledge amounts to '. One particular suggestion that can be understood in this light is *-semantics [ Pearl, 1989 ] . In *-semantics, we accept a default ' ! if given the knowledge ', the probability of : is very small. This small probability of the :' states gives us a license to ignore them. Although probability plays an important part in our decisions, we claim that we should also examine the utility of our actions. For example, while most people think that it is highly unlikely that they will die next year, they also believe that they should not accept this as a default assumption in the context of a decision as to whether or not to buy life insurance. In this context, the stakes are too high to ignore this outcome, even though it is unlikely. We suggest that the license to ignore a set should be given based on its impact on our decision. To paraphrase this view, we should accept Bird ! Fly if assuming that the bird flies cannot get us into too much trouble. To formalize our intuitions we examine decision-making in the framework of decision theory [ Luce and Raiffa, 1957 ] . Decision theory represents a decision problem using several components: a set of possible states, a probability measure over these sets, and a utility function that assigns to each action and state a numerical value. fl To appear in IJCAI'95. | [
1994
] | Train |
2,242 | 3 | Title: Density estimation by wavelet thresholding
Abstract: Density estimation is a commonly used test case for non-parametric estimation methods. We explore the asymptotic properties of estimators based on thresholding of empirical wavelet coefficients. Minimax rates of convergence are studied over a large range of Besov function classes B s;p;q and for a range of global L 0 p error measures, 1 p 0 < 1. A single wavelet threshold estimator is asymptotically minimax within logarithmic terms simultaneously over a range of spaces and error measures. In particular, when p 0 > p, some form of non-linearity is essential, since the minimax linear estimators are suboptimal by polynomial powers of n. A second approach, using an approximation of a Gaussian white noise model in a Mallows metric, is used Acknowledgements: We thank Alexandr Sakhanenko for helpful discussions and references to his work on Berry Esseen theorems used in Section 5. This work was supported in part by NSF DMS 92-09130. The second author would like to thank Universite de | [
1910,
2458,
2661
] | Train |
2,243 | 2 | Title: Using Precepts to Augment Training Set Learning an input whose value is don't-care in some
Abstract: are used in turn to approximate A. Empirical studies show that good results can be achieved with TSL [8, 11]. However, TSL has several drawbacks. Training set learners (e.g., backpropagation) are typically slow as they may require many passes over the training set. Also, there is no guarantee that, given an arbitrary training set, the system will find enough good critical features to get a reasonable approximation of A. Moreover, the number of features to be searched is exponential in the number of inputs, and TSL becomes computationally expensive [1]. Finally, the scarcity of interesting positive theoretical results suggests the difficulty of learning without sufficient a priori knowledge. The goal of learning systems is to generalize. Generalization is commonly based on the set of critical features the system has available. Training set learners typically extract critical features from a random set of examples. While this approach is attractive, it suffers from the exponential growth of the number of features to be searched. We propose to extend it by endowing the system with some a priori knowledge, in the form of precepts. Advantages of the augmented system are speedup, improved generalization, and greater parsimony. This paper presents a precept-driven learning algorithm. Its main features include: 1) distributed implementation, 2) bounded learning and execution times, and 3) ability to handle both correct and incorrect precepts. Results of simulations on real-world data demonstrate promise. This paper presents precept-driven learning (PDL). PDL is intended to overcome some of TSL's weaknesses. In PDL, the training set is augmented by a small set of precepts. A pair p = (i, o) in I O is called an example. A precept is an example in which some of the i-entries (inputs) are set to the special value don't-care. An input whose value is not don't-care is said to be asserted. If i has no effect on the value of the output. The use of the special value don't-care is therefore as a shorthand. A pair containing don't-care inputs represents as many examples as the product of the sizes of the input domains of its don't-care inputs. 1. Introduction | [
831,
2244,
2245
] | Train |
2,244 | 0 | Title: AN INCREMENTAL LEARNING MODEL FOR COMMONSENSE REASONING
Abstract: | [
2243
] | Train |
2,245 | 0 | Title: AN EFFICIENT METRIC FOR HETEROGENEOUS INDUCTIVE LEARNING APPLICATIONS IN THE ATTRIBUTE-VALUE LANGUAGE 1
Abstract: Many inductive learning problems can be expressed in the classical attribute-value language. In order to learn and to generalize, learning systems often rely on some measure of similarity between their current knowledge base and new information. The attribute-value language defines a heterogeneous multidimensional input space, where some attributes are nominal and others linear. Defining similarity, or proximity, of two points in such input spaces is non trivial. We discuss two representative homogeneous metrics and show examples of why they are limited to their own domains. We then address the issues raised by the design of a heterogeneous metric for inductive learning systems. In particular, we discuss the need for normalization and the impact of don't-care values. We propose a heterogeneous metric and evaluate it empirically on a simplified version of ILA. | [
87,
2243,
2471
] | Train |
2,246 | 6 | Title: Learning to model sequences generated by switching distributions
Abstract: We study efficient algorithms for solving the following problem, which we call the switching distributions learning problem. A sequence S = 1 2 : : : n , over a finite alphabet S is generated in the following way. The sequence is a concatenation of K runs, each of which is a consecutive subsequence. Each run is generated by independent random draws from a distribution ~p i over S, where ~p i is an element in a set of distributions f~p 1 ; : : : ; ~p N g. The learning algorithm is given this sequence and its goal is to find approximations of the distributions ~p 1 ; : : : ; ~p N , and give an approximate segmentation of the sequence into its constituting runs. We give an efficient algorithm for solving this problem and show conditions under which the algorithm is guaranteed to work with high probability. | [
2356,
2475
] | Train |
2,247 | 2 | Title: A Connectionist Architecture with Inherent Systematicity
Abstract: For connectionist networks to be adequate for higher level cognitive activities such as natural language interpretation, they have to generalize in a way that is appropriate given the regularities of the domain. Fodor and Pylyshyn (1988) identified an important pattern of regularities in such domains, which they called systematicity. Several attempts have been made to show that connectionist networks can generalize in accordance with these regularities, but not to the satisfaction of the critics. To address this challenge, this paper starts by establishing the implications of systematicity for connectionist solutions to the variable binding problem. Based on the work of Hadley (1994a), we argue that the network must generalize information it learns in one variable binding to other variable bindings. We then show that temporal synchrony variable binding (Shas-tri and Ajjanagadde, 1993) inherently generalizes in this way. Thereby we show that temporal synchrony variable binding is a connectionist architecture that accounts for systematicity. This is an important step in showing that connectionism can be an adequate architecture for higher level cognition. | [
2263,
2701
] | Train |
2,248 | 1 | Title: Heuristic for Improved Genetic Bin Packing
Abstract: University of Tulsa Technical Report UTULSA-MCS-93-8, May, 1993. Submitted to Information Processing Letters, May, 1993. | [
145,
163,
2296
] | Train |
2,249 | 1 | Title: Using a Distance Metric on Genetic Programs to Understand Genetic Operators
Abstract: I describe a distance metric called "edit" distance which quantifies the syntactic difference between two genetic programs. In the context of one specific problem, the 6 bit multiplexor, I use the metric to analyze the amount of new material introduced by different crossover operators, the difference among the best individuals of a population and the difference among the best individuals and the rest of the population. The relationships between these data and run performance are imprecise but they are sufficiently interesting to encourage encourage further investigation into the use of edit distance. | [
2175,
2271
] | Train |
2,250 | 1 | Title: The Impact of External Dependency in Genetic Programming Primitives
Abstract: Both control and data dependencies among primitives impact the behavioural consistency of subprograms in genetic programming solutions. Behavioural consistency in turn impacts the ability of genetic programming to identify and promote appropriate subprograms. We present the results of modelling dependency through a parameterized problem in which a subprogram exhibits internal and external dependency levels that change as the subprogram is successively combined into larger subsolutions. We find that the key difference between non-existent and "full" external dependency is a longer time to solution identification and a lower likelihood of success as shown by increased difficulty in identifying and promoting correct subprograms. | [
1696,
1940,
2175,
2271
] | Train |
2,251 | 1 | Title: A PARALLEL ISLAND MODEL GENETIC ALGORITHM FOR THE MULTIPROCESSOR SCHEDULING PROBLEM
Abstract: In this paper we compare the performance of a serial and a parallel island model Genetic Algorithm for solving the Multiprocessor Scheduling Problem. We show results using fixed and scaled problems both using and not using migration. We have found that in addition to providing a speedup through the use of parallel processing, the parallel island model GA with migration finds better quality solutions than the serial GA. | [
145,
163,
2296
] | Test |
2,252 | 1 | Title: Neural Programming and an Internal Reinforcement Policy
Abstract: An important reason for the continued popularity of Artificial Neural Networks (ANNs) in the machine learning community is that the gradient-descent backpropagation procedure gives ANNs a locally optimal change procedure and, in addition, a framework for understanding the ANN learning performance. Genetic programming (GP) is also a successful evolutionary learning technique that provides powerful parameterized primitive constructs. Unlike ANNs, though, GP does not have such a principled procedure for changing parts of the learned system based on its current performance. This paper introduces Neural Programming, a connectionist representation for evolving programs that maintains the benefits of GP. The connectionist model of Neural Programming allows for a regression credit-blame procedure in an evolutionary learning system. We describe a general method for an informed feedback mechanism for Neural Programming, Internal Reinforcement. We introduce an Internal Reinforcement procedure and demon strate its use through an illustrative experiment. | [
2220,
2271,
2277
] | Train |
2,253 | 5 | Title: Top-down Induction of Logical Decision Trees
Abstract: A first order framework for top-down induction of logical decision trees is introduced. Logical decision trees are more expressive than the flat logic programs typically induced by empirical inductive logic programming systems because logical decision trees introduce invented predicates and mix existential and universal quantification of variables. An implementation of the framework, the Tilde system, is presented and empirically evaluated. | [
2213,
2591
] | Train |
2,254 | 1 | Title: An Indexed Bibliography of Genetic Algorithms: Years 1957-1993 compiled by
Abstract: A first order framework for top-down induction of logical decision trees is introduced. Logical decision trees are more expressive than the flat logic programs typically induced by empirical inductive logic programming systems because logical decision trees introduce invented predicates and mix existential and universal quantification of variables. An implementation of the framework, the Tilde system, is presented and empirically evaluated. | [
2039,
2347
] | Train |
2,255 | 1 | Title: Evolutionary Learning of the Crossover Operator
Abstract: 1 Abstract | [
427,
2412
] | Train |
2,256 | 2 | Title: Improved Center Point Selection for Probabilistic Neural Networks
Abstract: Probabilistic Neural Networks (PNN) typically learn more quickly than many neural network models and have had success on a variety of applications. However, in their basic form, they tend to have a large number of hidden nodes. One common solution to this problem is to keep only a randomly-selected subset of the original training data in building the network. This paper presents an algorithm called the Reduced Probabilistic Neural Network (RPNN) that seeks to choose a better-than-random subset of the available instances to use as center points of nodes in the network. The algorithm tends to retain non-noisy border points while removing nodes with instances in regions of the input space that are highly homogeneous. In experiments on 22 datasets, the RPNN had better average generalization accuracy than two other PNN models, while requiring an average of less than one-third the number of nodes. | [
2597
] | Train |
2,257 | 1 | Title: Real-time Interactive Neuro-evolution
Abstract: In standard neuro-evolution, a population of networks is evolved in the task, and the network that best solves the task is found. This network is then fixed and used to solve future instances of the problem. Networks evolved in this way do not handle real-time interaction very well. It is hard to evolve a solution ahead of time that can cope effectively with all the possible environments that might arise in the future and with all the possible ways someone may interact with it. This paper proposes evolving feedforward neural networks online to create agents that improve their performance through real-time interaction. This approach is demonstrated in a game world where neural-network-controlled individuals play against humans. Through evolution, these individuals learn to react to varying opponents while appropriately taking into account conflicting goals. After initial evaluation offline, the population is allowed to evolve online, and its performance improves considerably. The population not only adapts to novel situations brought about by changing strategies in the opponent and the game layout, but it also improves its performance in situations that it has already seen in offline training. This paper will describe an implementation of online evolution and shows that it is a practical method that exceeds the performance of offline evolution alone. | [
22,
247,
1767,
1768,
2444
] | Test |
2,258 | 2 | Title: LU TP 93-24 Predicting System Loads with Artificial Neural
Abstract: Networks Methods and Results from Abstract: We devise a feed-forward Artificial Neural Network (ANN) procedure for predicting utility loads and present the resulting predictions for two test problems given by "The Great Energy Predictor Shootout The First Building Data Analysis and Prediction Competition" [1]. Key ingredients in our approach are a method (ffi -test) for determining relevant inputs and the Multilayer Perceptron. These methods are briefly reviewed together with comments on alternative schemes like fitting to polynomials and the use of recurrent networks. | [
427,
1887
] | Train |
2,259 | 1 | Title: An Experimental Analysis of Schema Creation, Propagation and Disruption in Genetic Programming
Abstract: In this paper we first review the main results in the theory of schemata in Genetic Programming (GP) and summarise a new GP schema theory which is based on a new definition of schema. Then we study the creation, propagation and disruption of this new form of schemata in real runs, for standard crossover, one-point crossover and selection only. Finally, we discuss these results in the light our GP schema theorem. | [
163,
1257,
1959,
2175,
2261,
2271
] | Train |
2,260 | 2 | Title: Radial Basis Functions for Process Control
Abstract: Radial basis function (RBFs) neural networks provide an attractive method for high dimensional nonparametric estimation for use in nonlinear control. They are faster to train than conventional feedforward networks with sigmoidal activation networks ("backpropagation nets"), and provide a model structure better suited for adaptive control. This article gives a brief survey of the use of RBFs and then introduces a new statistical interpretation of radial basis functions and a new method of estimating the parameters, using the EM algorithm. This new statistical interpretation allows us to provide confidence limits on predictions made using the networks. | [
611,
2501
] | Test |
2,261 | 1 | Title: Genetic Programming with One-Point Crossover and Point Mutation
Abstract: Technical Report: CSRP-97-13 April 1997 Abstract In recent theoretical and experimental work on schemata in genetic programming we have proposed a new simpler form of crossover in which the same crossover point is selected in both parent programs. We call this operator one-point crossover because of its similarity with the corresponding operator in genetic algorithms. One point crossover presents very interesting properties from the theory point of view. In this paper we describe this form of crossover as well as a new variant called strict one-point crossover highlighting their useful theoretical and practical features. We also present experimental evidence which shows that one-point crossover compares favourably with standard crossover. | [
1719,
2087,
2206,
2259
] | Test |
2,262 | 2 | Title: OPTIMAL ASYMPTOTIC IDENTIFICATION UNDER BOUNDED DISTURBANCES
Abstract: This paper investigates the intrinsic limitation of worst-case identification of LTI systems using data corrupted by bounded disturbances, when the unknown plant is known to belong to a given model set. This is done by analyzing the optimal worst-case asymptotic error achievable by performing experiments using any bounded inputs and estimating the plant using any identification algorithm. First, it is shown that under some topological conditions on the model set, there is an identification algorithm which is asymptotically optimal for any input. Characterization of the optimal asymptotic error as a function of the inputs is also obtained. These results hold for any error metric and disturbance norm. Second, these general results are applied to three specific identification problems: identification of stable systems in the ` 1 norm, identification of stable rational systems in the H 1 norm, and identification of unstable rational systems in the gap metric. For each of these problems, the general characterization of optimal asymptotic error is used to find near-optimal inputs to minimize the error. | [
2236,
2435,
2542
] | Train |
2,263 | 2 | Title: A Connectionist Architecture for Learning to Parse
Abstract: We present a connectionist architecture and demonstrate that it can learn syntactic parsing from a corpus of parsed text. The architecture can represent syntactic constituents, and can learn generalizations over syntactic constituents, thereby addressing the sparse data problems of previous connectionist architectures. We apply these Simple Synchrony Networks to mapping sequences of word tags to parse trees. After training on parsed samples of the Brown Corpus, the networks achieve precision and recall on constituents that approaches that of statistical methods for this task. | [
2247,
2701
] | Train |
2,264 | 1 | Title: Evolutionary Computation in Air Traffic Control Planning
Abstract: Air Traffic Control is involved in the real-time planning of aircraft trajectories. This is a heavily constrained optimization problem. We concentrate on free-route planning, in which aircraft are not required to fly over way points. The choice of a proper representation for this real-world problem is non-trivial. We propose a two level representation: one level on which the evolutionary operators work, and a derived level on which we do calculations. Furthermore we show that a specific choice of the fitness function is important for finding good solutions to large problem instances. We use a hybrid approach in the sense that we use knowledge about air traffic control by using a number of heuristics. We have built a prototype of a planning tool, and this resulted in a flexible tool for generating a free-route planning of low cost, for a number of aircraft. | [
2519
] | Train |
2,265 | 1 | Title: AN APPROACH TO A PROBLEM IN NETWORK DESIGN USING GENETIC ALGORITHMS
Abstract: Air Traffic Control is involved in the real-time planning of aircraft trajectories. This is a heavily constrained optimization problem. We concentrate on free-route planning, in which aircraft are not required to fly over way points. The choice of a proper representation for this real-world problem is non-trivial. We propose a two level representation: one level on which the evolutionary operators work, and a derived level on which we do calculations. Furthermore we show that a specific choice of the fitness function is important for finding good solutions to large problem instances. We use a hybrid approach in the sense that we use knowledge about air traffic control by using a number of heuristics. We have built a prototype of a planning tool, and this resulted in a flexible tool for generating a free-route planning of low cost, for a number of aircraft. | [
163,
2347
] | Train |
2,266 | 3 | Title: A Gentle Tutorial of the EM Algorithm and its Application to Parameter Estimation for Gaussian
Abstract: We describe the maximum-likelihood parameter estimation problem and how the Expectation-Maximization (EM) algorithm can be used for its solution. We first describe the abstract form of the EM algorithm as it is often given in the literature. We then develop the EM parameter estimation procedure for two applications: 1) finding the parameters of a mixture of Gaussian densities, and 2) finding the parameters of a hidden Markov model (HMM) (i.e., the Baum-Welch algorithm) for both discrete and Gaussian mixture observation models. We derive the update equations in fairly explicit detail but we do not prove any convergence properties. We try to emphasize intuition rather than mathematical rigor. | [
74,
345,
2421
] | Validation |
2,267 | 1 | Title: Evolving Optimal Neural Networks Using Genetic Algorithms with Occam's Razor
Abstract: Genetic algorithms have been used for neural networks in two main ways: to optimize the network architecture and to train the weights of a fixed architecture. While most previous work focuses on only one of these two options, this paper investigates an alternative evolutionary approach called Breeder Genetic Programming (BGP) in which the architecture and the weights are optimized simultaneously. The genotype of each network is represented as a tree whose depth and width are dynamically adapted to the particular application by specifically defined genetic operators. The weights are trained by a next-ascent hillclimbing search. A new fitness function is proposed that quantifies the principle of Occam's razor. It makes an optimal trade-off between the error fitting ability and the parsimony of the network. Simulation results on two benchmark problems of differing complexity suggest that the method finds minimal size networks on clean data. The experiments on noisy data show that using Occam's razor not only improves the generalization performance, it also accel erates the convergence speed of evolution. fl Published in Complex Systems, 7(3): 199-220, 1993 | [
2196
] | Test |
2,268 | 2 | Title: SPERT: A VLIW/SIMD Microprocessor for Artificial Neural Network Computations
Abstract: SPERT (Synthetic PERceptron Testbed) is a fully programmable single chip microprocessor designed for efficient execution of artificial neural network algorithms. The first implementation will be in a 1.2 m CMOS technology with a 50MHz clock rate, and a prototype system is being designed to occupy a double SBus slot within a Sun Sparcstation. SPERT will sustain over 300 fi 10 6 connections per second during pattern classification, and around 100 fi 10 6 connection updates per second while running the popular error backpropagation training algorithm. This represents a speedup of around two orders of magnitude over a Sparcstation-2 for algorithms of interest. An earlier system produced by our group, the Ring Array Processor (RAP), used commercial DSP chips. Compared with a RAP multiprocessor of similar performance, SPERT represents over an order of magnitude reduction in cost for problems where fixed-point arithmetic is satisfactory. fl International Computer Science Institute, 1947 Center Street, Berkeley, CA 94704 | [
1753,
2275,
2445
] | Train |
2,269 | 1 | Title: Some Steps Towards a Form of Parallel Distributed Genetic Programming
Abstract: Genetic Programming is a method of program discovery consisting of a special kind of genetic algorithm capable of operating on nonlinear chromosomes (parse trees) representing programs and an interpreter which can run the programs being optimised. This paper describes PDGP (Parallel Distributed Genetic Programming), a new form of genetic programming which is suitable for the development of fine-grained parallel programs. PDGP is based on a graph-like representation for parallel programs which is manipulated by crossover and mutation operators which guarantee the syntactic correctness of the offspring. The paper describes these operators and reports some preliminary results obtained with this paradigm. | [
2277
] | Train |
2,270 | 2 | Title: Using generative models for handwritten digit recognition
Abstract: Genetic Programming is a method of program discovery consisting of a special kind of genetic algorithm capable of operating on nonlinear chromosomes (parse trees) representing programs and an interpreter which can run the programs being optimised. This paper describes PDGP (Parallel Distributed Genetic Programming), a new form of genetic programming which is suitable for the development of fine-grained parallel programs. PDGP is based on a graph-like representation for parallel programs which is manipulated by crossover and mutation operators which guarantee the syntactic correctness of the offspring. The paper describes these operators and reports some preliminary results obtained with this paradigm. | [
480,
667,
2043
] | Train |
2,271 | 1 | Title: How Fitness Structure Affects Subsolution Acquisition in Genetic Programming
Abstract: We define fitness structure in genetic programming to be the mapping between the subprograms of a program and their respective fitness values. This paper shows how various fitness structures of a problem with independent subsolutions relate to the acquisition of sub-solutions. The rate of subsolution acquisition is found to be directly correlated with fitness structure whether that structure is uniform, linear or exponential. An understanding of fitness structure provides partial insight into the complicated relationship between fitness function and the outcome of genetic programming's search. | [
2238,
2249,
2250,
2252,
2259
] | Validation |
2,272 | 2 | Title: Rapid learning of binding-match and binding-error detector circuits via long-term potentiation
Abstract: It is argued that the memorization of events and situations (episodic memory) requires the rapid formation of neural circuits responsive to binding errors and binding matches. While the formation of circuits responsive to binding matches can be modeled by associative learning mechanisms, the rapid formation of circuits responsive to binding errors is difficult to explain given their seemingly paradoxical behavior; such a circuit must be formed in response to the occurrence of a binding (i.e., a particular pattern in the input), but subsequent to its formation, it must not fire anymore in response to the occurrence of the very binding (i.e., pattern) that led to its formation. A plausible account of the formation of such circuits has not been offered. A computational model is described that demonstrates how a transient pattern of activity representing an event can lead to the rapid formation of circuits for detecting bindings and binding errors as a result of long-term potentiation within structures whose architecture and circuitry are similar to those of the hippocampal formation, a neural structure known to be critical to episodic memory. The model exhibits a high memory capacity and is robust against limited amounts of diffuse cell loss. The model also offers an alternate interpretation of the functional role of region CA3 in the formation of episodic memories, and predicts the nature of memory impairment that would result from damage to various regions of the hippocampal formation. | [
1176,
1866
] | Train |
2,273 | 6 | Title: Learning Harmonic Progression Using Markov Models EECS545 Project
Abstract: It is argued that the memorization of events and situations (episodic memory) requires the rapid formation of neural circuits responsive to binding errors and binding matches. While the formation of circuits responsive to binding matches can be modeled by associative learning mechanisms, the rapid formation of circuits responsive to binding errors is difficult to explain given their seemingly paradoxical behavior; such a circuit must be formed in response to the occurrence of a binding (i.e., a particular pattern in the input), but subsequent to its formation, it must not fire anymore in response to the occurrence of the very binding (i.e., pattern) that led to its formation. A plausible account of the formation of such circuits has not been offered. A computational model is described that demonstrates how a transient pattern of activity representing an event can lead to the rapid formation of circuits for detecting bindings and binding errors as a result of long-term potentiation within structures whose architecture and circuitry are similar to those of the hippocampal formation, a neural structure known to be critical to episodic memory. The model exhibits a high memory capacity and is robust against limited amounts of diffuse cell loss. The model also offers an alternate interpretation of the functional role of region CA3 in the formation of episodic memories, and predicts the nature of memory impairment that would result from damage to various regions of the hippocampal formation. | [
2360
] | Train |
2,274 | 1 | Title: Specialization in Populations of Artificial Neural Networks
Abstract: Specialization in populations of artificial neural networks is studied. Organisms with both fixed and evolvable fitness formulae are placed in isolated and shared environments, and the emerged behaviors are compared. An evolvable fitness formula specifies, that the evaluation measure is let free to evolve, and we obtain co-evolution of the expressed behavior and the individual evolvable fitness formula. In an isolated environment a generalist behavior emerges when organisms have a fixed fitness formula, and a specialist behavior emerges when organisms have individual evolvable fitness formulae. A population diversification analysis shows, that almost all organisms in a population in an isolated environment converge towards the same behavioral strategy, while we find, that competition can act to provide population diversification in populations of organisms in a shared environment. | [
163,
2237
] | Test |
2,275 | 2 | Title: Connectionist Layered Object-Oriented Network Simulator (CLONES): User's Manual minimize the learning curve for using CLONES,
Abstract: CLONES is a object-oriented library for constructing, training and utilizing layered connectionist networks. The CLONES library contains all the object classes needed to write a simulator with a small amount of added source code (examples are included). The size of experimental ANN programs is greatly reduced by using an object-oriented library; at the same time these programs are easier to read, write and evolve. The library includes database, network behavior and training procedures that can be customized by the user. It is designed to run efficiently on data parallel computers (such as the RAP [6] and SPERT [1]) as well as uniprocessor workstations. While efficiency and portability to parallel computers are the primary goals, there are several secondary design goals: 3. allow heterogeneous algorithms and training procedures to be interconnected and trained together. Within these constraints we attempt to maximize the variety of artificial neural net work algorithms that can be supported. | [
1120,
2191,
2268,
2445,
2522
] | Train |
2,276 | 0 | Title: Finding Analogues for Innovative Design
Abstract: Knowledge Systems Laboratory March 1995 Report No. KSL 95-32 | [
30,
486,
1864
] | Test |
2,277 | 1 | Title: Discovery of Symbolic, Neuro-Symbolic and Neural Networks with Parallel Distributed Genetic Programming
Abstract: Technical Report: CSRP-96-14 August 1996 Abstract Genetic Programming is a method of program discovery consisting of a special kind of genetic algorithm capable of operating on parse trees representing programs and an interpreter which can run the programs being optimised. This paper describes Parallel Distributed Genetic Programming (PDGP), a new form of genetic programming which is suitable for the development of parallel programs in which symbolic and neural processing elements can be combined a in free and natural way. PDGP is based on a graph-like representation for parallel programs which is manipulated by crossover and mutation operators which guarantee the syntactic correctness of the offspring. The paper describes these operators and reports some results obtained with the exclusive-or problem. | [
1277,
1931,
2252,
2269,
2624
] | Train |
2,278 | 2 | Title: Routing in Optical Multistage Interconnection Networks: a Neural Network Solution
Abstract: There has been much interest in using optics to implement computer interconnection networks. However, there has been little discussion of any routing methodologies besides those already used in electronics. In this paper, a neural network routing methodology is proposed that can generate control bits for a broad range of optical multistage interconnection networks (OMINs). Though we present no optical implementation of this methodology, we illustrate its control for an optical interconnection network. These OMINs can be used as communication media for distributed computing systems. The routing methodology makes use of an Artificial Neural Network (ANN) that functions as a parallel computer for generating the routes. The neural network routing scheme can be applied to electrical as well as optical interconnection networks. However, since the ANN can be implemented using optics, this routing approach is especially appealing for an optical computing environment. Although the ANN does not always generate the best solution, the parallel nature of the ANN computation may make this routing scheme faster than conventional routing approaches, especially for OMINs that have an irregular structure. Furthermore, the ANN router is fault-tolerant. Results are shown for generating routes in a 16 fi 16, 3-stage OMIN. | [
2284
] | Train |
2,279 | 2 | Title: Quicknet on MultiSpert: Fast Parallel Neural Network Training
Abstract: The MultiSpert parallel system is a straight-forward extension of the Spert workstation accelerator, which is predominantly used in speech recognition research at ICSI. In order to deliver high performance for Artificial Neural Network training without requiring changes to the user interfaces, the exisiting Quicknet ANN library was modified to run on MultiSpert. In this report, we present the algorithms used in the parallelization of the Quicknet code and analyse their communication and computation requirements. The resulting performance model yields a better understanding of system speed-ups and potential bottlenecks. Experimental results from actual training runs validate the model and demonstrate the achieved performance levels. | [
1806,
2579
] | Train |
2,280 | 1 | Title: A GENETIC ALGORITHM FOR FRAGMENT ALLOCATION IN A DISTRIBUTED DATABASE SYSTEM
Abstract: In this paper we explore the distributed database allocation problem, which is intractable. We also discuss genetic algorithms and how they have been used successfully to solve combinatorial problems. Our experimental results show the GA to be far superior to the greedy heuristic in obtaining optimal and near optimal fragment placements for the allocation problem with various data sets. | [
145,
163,
2286
] | Test |
2,281 | 2 | Title: GENE REGULATION AND BIOLOGICAL DEVELOPMENT IN NEURAL NETWORKS: AN EXPLORATORY MODEL
Abstract: In this paper we explore the distributed database allocation problem, which is intractable. We also discuss genetic algorithms and how they have been used successfully to solve combinatorial problems. Our experimental results show the GA to be far superior to the greedy heuristic in obtaining optimal and near optimal fragment placements for the allocation problem with various data sets. | [
1134,
2429
] | Train |
2,282 | 5 | Title: The ILP description learning problem: Towards a general model-level definition of data mining in ILP
Abstract: stefan.wrobel@gmd.de, saso.dzeroski@gmd.de Proc. FGML-95, Annual Workshop of the GI Special Interest Group Machine Learning (GI FG 1.1.3), ed. K. Morik and J. Herrmann, Research Report 580, Univ.Dortmund, 1995. Abstract The task of discovering interesting regularities in (large) sets of data (data mining, knowledge discovery) has recently met with increased interest in Machine Learning in general and in Inductive Logic Programming (ILP) in particular. However, while there is a widely accepted definition for the task of concept learning from examples in ILP, definitions for the data mining task have been proposed only recently. In this paper, we examine these so-called "non-monotonic semantics" definitions and show that non-monotonicity is only an incidental property of the data mining learning task, and that this task makes perfect sense without such an assumption. We therefore introduce and define a generalized definition of the data mining task called the ILP description learning problem and discuss its properties and relation to the traditional concept learning (prediction) learning problem. Since our characterization is entirely on the level of models, the definition applies independently of the chosen hypothesis language. | [
1686,
2217,
2426
] | Test |
2,283 | 2 | Title: Predictive Control of Opto-Electronic Reconfigurable Interconnection Networks Using Neural Networks
Abstract: Opto-electronic reconfigurable interconnection networks are limited by significant control latency when used in large multiprocessor systems. This latency is the time required to analyze the current traffic and reconfigure the network to establish the required paths. The goal of latency hiding is to minimize the effect of this control overhead. In this paper, we introduce a technique that performs latency hiding by learning the patterns of communication traffic and using that information to anticipate the need for communication paths. Hence, the network provides the required communication paths before a request for a path is made. In this study, the communication patterns (memory accesses) of a parallel program are used as input to a time delay neural network (TDNN) to perform online training and prediction. These predicted communication patterns are used by the interconnection network controller that provides routes for the memory requests. Based on our experiments, the neural network was able to learn highly repetitive communication patterns, and was thus able to predict the allocation of communication paths, resulting in a reduction of communication latency. Communication latency is a significant issue in the design of lar ge scale multiprocessor systems. Point-to-point interconnection networks, which directly connect all processors and/or memories, provide minimum communication latency but suffer from high cost and limited scalability. A plethora of electr onic singlestage and multistage networks have been pr oposed, designed and built [Siegel90, Leighton93]. An alternative is the use of opto-electr onic reconfigurable interconnection networks which offer a limited number of high bandwidth communication channels configured on demand, to satisfy the r equired communication traffic [CLMQ94b]. A network controller determines the network configuration based on processor requests. Once the controller provides the optical communication paths requested, the communication proceeds at high speeds. Hence, the end-to-end latency incurred by such networks can be characterized by three components: control time, which is the time needed to determine the new network configuration and to physically establish the paths; launch time, the time to transmit the data into the network; and y time, the time needed for the message to travel through the network to its final destination. For high bandwidth short distance networks, the control time dominates the overall | [
2284
] | Validation |
2,284 | 2 | Title: Performance of On-Line Learning Methods in Predicting Multiprocessor Memory Access Patterns
Abstract: Technical Report UMIACS-TR-96-59 and CS-TR-3676 Institute for Advanced Computer Studies University of Maryland College Park, MD 20742 Abstract Shared memory multiprocessors require reconfigurable interconnection networks (INs) for scalability. These INs are reconfigured by an IN control unit. However, these INs are often plagued by undesirable reconfiguration time that is primarily due to control latency, the amount of time delay that the control unit takes to decide on a desired new IN configuration. To reduce control latency, a trainable prediction unit (PU) was devised and added to the IN controller. The PUs job is to anticipate and reduce control configuration time, the major component of the control latency. Three different on-line prediction techniques were tested to learn and predict repetitive memory access patterns for three typical parallel processing applications, the 2-D relaxation algorithm, matrix multiply and Fast Fourier Transform. The predictions were then used by a routing control algorithm to reduce control latency by configuring the IN to provide needed memory access paths before they were requested. Three prediction techniques were used and tested: 1). a Markov predictor, 2). a linear predictor and 3). a time delay neural network (TDNN) predictor. As expected, different predictors performed best on different applications, however, the TDNN produced the best overall results. | [
74,
1293,
2278,
2283
] | Validation |
2,285 | 3 | Title: Simulation Based Bayesian Nonparametric Regression Methods
Abstract: Technical Report UMIACS-TR-96-59 and CS-TR-3676 Institute for Advanced Computer Studies University of Maryland College Park, MD 20742 Abstract Shared memory multiprocessors require reconfigurable interconnection networks (INs) for scalability. These INs are reconfigured by an IN control unit. However, these INs are often plagued by undesirable reconfiguration time that is primarily due to control latency, the amount of time delay that the control unit takes to decide on a desired new IN configuration. To reduce control latency, a trainable prediction unit (PU) was devised and added to the IN controller. The PUs job is to anticipate and reduce control configuration time, the major component of the control latency. Three different on-line prediction techniques were tested to learn and predict repetitive memory access patterns for three typical parallel processing applications, the 2-D relaxation algorithm, matrix multiply and Fast Fourier Transform. The predictions were then used by a routing control algorithm to reduce control latency by configuring the IN to provide needed memory access paths before they were requested. Three prediction techniques were used and tested: 1). a Markov predictor, 2). a linear predictor and 3). a time delay neural network (TDNN) predictor. As expected, different predictors performed best on different applications, however, the TDNN produced the best overall results. | [
2138,
2311
] | Train |
2,286 | 1 | Title: A Genetic Algorithm for File and Task Placement in a Distributed System
Abstract: In this paper we explore the distributed file and task placement problem, which is intractable. We also discuss genetic algorithms and how they have been used successfully to solve combinatorial problems. Our experimental results show the GA to be far superior to the greedy heuristic in obtaining optimal and near optimal file and task placements for the problem with various data sets. | [
145,
163,
2280
] | Train |
2,287 | 3 | Title: Consistency of Posterior Distributions for Neural Networks
Abstract: In this paper we show that the posterior distribution for feedforward neural networks is asymptotically consistent. This paper extends earlier results on universal approximation properties of neural networks to the Bayesian setting. The proof of consistency embeds the problem in a density estimation problem, then uses bounds on the bracketing entropy to show that the posterior is consistent over Hellinger neighborhoods. It then relates this result back to the regression setting. We show consistency in both the setting of the number of hidden nodes growing with the sample size, and in the case where the number of hidden nodes is treated as a parameter. Thus we provide a theoretical justification for using neural networks for nonparametric regression in a Bayesian framework. | [
560,
2315
] | Validation |
2,288 | 3 | Title: Anytime Influence Diagrams
Abstract: In this paper we show that the posterior distribution for feedforward neural networks is asymptotically consistent. This paper extends earlier results on universal approximation properties of neural networks to the Bayesian setting. The proof of consistency embeds the problem in a density estimation problem, then uses bounds on the bracketing entropy to show that the posterior is consistent over Hellinger neighborhoods. It then relates this result back to the regression setting. We show consistency in both the setting of the number of hidden nodes growing with the sample size, and in the case where the number of hidden nodes is treated as a parameter. Thus we provide a theoretical justification for using neural networks for nonparametric regression in a Bayesian framework. | [
1759,
2697
] | Validation |
2,289 | 0 | Title: An Interactive Planning Architecture The Forest Fire Fighting case
Abstract: This paper describes an interactive planning system that was developed inside an Intelligent Decision Support System aimed at supporting an operator when planning the initial attack to forest fires. The planning architecture rests on the integration of case-based reasoning techniques with constraint reasoning techniques exploited, mainly, for performing temporal reasoning on temporal metric information. Temporal reasoning plays a central role in supporting interactive functions that are provided to the user when performing two basic steps of the planning process: plan adaptation and resource scheduling. A first prototype was integrated with a situation assessment and a resource allocation manager subsystem and is currently being tested. | [
1804,
1805
] | Train |
2,290 | 5 | Title: A Comparison of Pruning Methods for Relational Concept Learning
Abstract: Pre-Pruning and Post-Pruning are two standard methods of dealing with noise in concept learning. Pre-Pruning methods are very efficient, while Post-Pruning methods typically are more accurate, but much slower, because they have to generate an overly specific concept description first. We have experimented with a variety of pruning methods, including two new methods that try to combine and integrate pre- and post-pruning in order to achieve both accuracy and efficiency. This is verified with test series in a chess position classification task. | [
344,
378,
585,
1275,
2213,
2291
] | Train |
2,291 | 5 | Title: Top-Down Pruning in Relational Learning
Abstract: Pruning is an effective method for dealing with noise in Machine Learning. Recently pruning algorithms, in particular Reduced Error Pruning, have also attracted interest in the field of Inductive Logic Programming. However, it has been shown that these methods can be very inefficient, because most of the time is wasted for generating clauses that explain noisy examples and subsequently pruning these clauses. We introduce a new method which searches for good theories in a top-down fashion to get a better starting point for the pruning algorithm. Experiments show that this approach can significantly lower the complexity of the task without losing predictive accuracy. | [
344,
378,
585,
1275,
2290
] | Train |
2,292 | 3 | Title: Logarithmic-Time Updates and Queries in Probabilistic Networks
Abstract: Traditional databases commonly support efficient query and update procedures that operate in time which is sublinear in the size of the database. Our goal in this paper is to take a first step toward dynamic reasoning in probabilistic databases with comparable efficiency. We propose a dynamic data structure that supports efficient algorithms for updating and querying singly connected Bayesian networks. In the conventional algorithm, new evidence is absorbed in time O(1) and queries are processed in time O(N ), where N is the size of the network. We propose an algorithm which, after a preprocessing phase, allows us to answer queries in time O(log N ) at the expense of O(log N ) time per evidence absorption. The usefulness of sub-linear processing time manifests itself in applications requiring (near) real-time response over large probabilistic databases. We briefly discuss a potential application of dynamic probabilistic reasoning in computational biology. | [
1111,
1899,
2140
] | Test |
2,293 | 3 | Title: Localized Partial Evaluation of Belief Networks
Abstract: in the network. Often, however, an application will not need information about every node in the network nor will it need exact probabilities. We present the localized partial evaluation (LPE) propagation algorithm, which computes interval bounds on the marginal probability of a specified query node by examining a subset of the nodes in the entire network. Conceptually, LPE ignores parts of the network that are "too far away" from the queried node to have much impact on its value. LPE has the "anytime" property of being able to produce better solutions (tighter intervals) given more time to consider more of the network. | [
1937
] | Validation |
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