ppxscal/embedding_network huggingface dataset:
On the Problem of Finding Natural Computational Complexity Measures
Authors: Juris Hartmanis
Venue:  (1973)

To develop an abstract theory which deals with the quantitative aspects of computing we need a deeper understanding of how to define ``natural'''' computational complexity measures axiomatically. To this end, this paper summarizess the principal properties which hold for some natural complexity measures but not for all measures and which have been proposed as desirable properties of natural measuress. The paper discusses the nature of these properties, studies their interrelations and their possible values towards defining natural computational complexity measures. A number off open problems are discussed and directions for further research are suggested.
Robustness to inflated subscription in multicast congestion control
Authors: Sergey Gorinsky, Sugat Jain, Harrick Vin, Yongguang Zhang
Venue: Proceedings of the 2003 conference on Applications, technologies, architectures, and protocols for computer communications (2003)

Group subscription is a useful mechanism for multicast congestion control: RLM, RLC, FLID-DL, and WEBRC form a promising line of multi-group protocols where receivers provide no feedback to the sender but control congestion via group membership regulation. Unfortunately, the group subscription mechanism also offers receivers an opportunity to elicit self-beneficial bandwidth allocations. In particular, a misbehaving receiver can ignoreguidelines for group subscription and choose an unfairly high subscription level in a multi-group multicast session. This poses a serious threat to fairness of bandwidth allocation. In this paper, we present the first solution for the problem of inflated subscription. Our design guards access to multicast groups with dynamic keys and consists of two independent components: DELTA (Distribution of ELigibility To Access) -- a novel method for in-band distribution of group keys to receivers that are eligible to access the groups according to the congestion control protocol, and SIGMA (Secure Internet Group Management Architecture) -- a generic architecture for key-based group access at edge routers.
To feel or not to feel: the role of affect in human-computer interaction
Authors: Eva Hudlicka
Venue: International Journal of Human-Computer Studies (2003)

The past decade has witnessed an unprecedented growth in user interface and human-computer interaction (HCI) technologies and methods. The synergy of technological and methodological progress on the one hand, and changing user expectations on the other, are contributing to a redefinition of the requirements for effective and desirable human-computer interaction. A key component of these emerging requirements, and of effective HCI in general, is the ability of these emerging systems to address user affect. The objective of this special issue is to provide an introduction to the emerging research area of affective HCI, some of the available methods and techniques, and representative systems and applications.
Slip Complexity in a Crustal-Plane Model of an Earthquake Fault
Authors: Christopher R. Myers, Bruce E. Shaw, J. S. Langer
Venue:  (1994)

We study numerically the behavior of a two-dimensional elastic plate (a crustal plane) that terminates along one of its edges at a homogeneous fault boundary. Slip-weakening friction at the boundary, inertial dynamics in the bulk, and uniform slow loading via elastic coupling to a substrate combine to produce a complex, deterministically chaotic sequence of slipping events. We observe a power-law distribution of small to moderately large events and an excess of very large events. For the smaller events, the moments scale with the rupture length in a manner that is consistent with seismological observations. For the largest events, rupture occurs in the form of narrow propagating pulses.
Cyclic Just-In-Time Sequences Are Optimal
Authors: Wieslaw Kubiak
Venue: Journal of Global Optimization (2003)

Consider the Product Rate Variation problem. Given n products 1,&hellip;,i,&hellip;,n, and n positive integer demands d1,&hellip;, di,&hellip;,dn. Find a sequence &alpha;=&alpha;1,&hellip;,&alpha;T, T=\sumi=1ndi, of the products, where product i occurs exactly di times that always keeps the actual production level, equal the number of product i occurrences in the prefix &alpha;1,&hellip;, &alpha;t, t=1,&hellip;,T, and the desired production level, equal rit, where ri=di/T, of each product i as close to each other as possible. The problem is one of the most fundamental problems in sequencing flexible just-in-time production systems. We show that if &beta; is an optimal sequence for d1,&hellip;,di,&hellip;,dn, then concatenation &beta;m of m copies of &beta; is an optimal sequence for md1,&hellip;, mdi,&hellip;,mdn.
Multiple positive solutions for first order nonlinear impulsive integro-differential equations in a Banach space
Authors: Dajun Guo
Venue: Applied Mathematics and Computation (2003)

By using the fixed point index theory, the author obtains the existence of two positive solutions for a boundary value problem of first order nonlinear impulsive integro-differential equations on an infinite interval with an infinite number of impulsive times in a real Banach space.
Greedy Approximation Algorithms for K-Medians by Randomized Rounding
Authors: Neal E. Young
Venue:  (1999)

We give an improved approximation algorithm for the general k-medians problem. Given any \epsilon<0, the algorithm finds a solution of total distance at most D(1+\epsilon) using at most k ln(n+n/\epsilon) medians (a.k.a. sites), provided some solution of total distance D using k medians exists. This improves over the best previous bound (w.r.t. the number of medians) by a factor of \Omega(1/\epsilon) provided 1/\epsilon=n^O(1). The algorithm is a greedy algorithm, derived using the method of oblivious randomized rounding. It requires at most k ln(n+n/\epsilon) linear-time iterations. We also derive algorithms for fractional and weighted variants of the problem.
An Empirical Investigation of the Forward Checking Algorithm and its Derivatives
Authors: Michael J. Dent, Robert E. Mercer
Venue: Proceedings of the 8th International Conference on Tools with Artificial Intelligence (1996)

Forward Checking (FC) is one of the most popular algorithms used to solve Constraint Satisfaction Problems. A lazy variant of FC has been proposed called Minimal Forward Checking (MFC). Previous empirical results suggest that MFC substantially outperforms FC when the Fail First (FF) heuristic is not used. These results also suggest that the laziness of MFC can have substantial negative effects when the FF heuristic is used. To overcome this problem two extensions to the MFC algorithm are proposed, a new heuristic, called EXtra Pruning (EXP), and the addition of Conflict-directed BackJumping (CBJ). An empirical investigation on a large test suite of hard randomly generated problems suggests that adding both EXP and CBJ to MFC-FF (MFC-CBJ-EXP-FF) is the best forward checking algorithm. Some theoretical relationships among the various algorithms are discussed.
Impact of Polling Strategy on Capacity of 802.11 Based Wireless Multimedia LANs
Authors: Ravindra S. Ranasinghe, Lachlan L. H. Andrew, David Everitt
Venue: Proceedings of the 7th IEEE International Conference on Networks (1999)

Wireless local area networks are a viable technology to support multimedia traffic. One of the prominent wireless local area network standards being adopted as a mature technology is the IEEE 802.11 standard. In wireless multimedia networks, mobile stations will be capable of generating a heterogeneous traffic mix and therefore it is crucial to devise an efficient bandwidth allocation scheme to satisfy the quality of service requirements of each traffic class. In this paper we present a distributed fair queuing scheme which is compatible with the 802.11 standard and can manage bandwidth allocation for delay sensitive traffic. The performance of the proposed scheme is evaluated by simulation, showing that a distributed version of deficit round robin outperforms the standard round robin service discipline from a capacity viewpoint.
A Biologically Meaningful Model for Comparing Molecular Phylogenies
Authors: Boris Mirkin, Ilya Muchnik, Temple F. Smith
Venue:  (1995)

In the framework of the problem of combining different gene trees into a unique species phylogeny, a model for duplication/speciation/loss events along the evolutionary tree is introduced. The model is employed for embedding a plylogeny tree into another one via so called Duplication/Speciation principle requiring that the gene duplicated evolves in such a way that any of the contemporary species involved bears only one of the gene copies diverged. The number of biologically meaningful elements in the embedding result (duplications, losses, information gaps) is considered a (asymmetric) dissimilarity measure between the trees. The model duplication concept is compared with that one defined previously in terms of a mapping procedure for the trees. A graph-theoretic reformulation of the measure is derived.
Fast Dynamic Reconfiguration in Irregular Networks
Authors: Olav Lysne, José Duato
Venue: Proceedings of the Proceedings of the 2000 International Conference on Parallel Processing (2000)

Exploitation of the wiring flexibility in Networks of Workstations demands configuration methods that can handle dynamic changes in irregular topologies. During reconfiguration of a network based on virtual cut-through or wormhole switching, however, deadlocks in the transition phase between the old and the new routing function must be avoided. The avoidance of such deadlocks will in general make the performance of the network suffer during reconfiguration. Keeping reconfiguration time as short as possible, and leaving as much as possible of the network untouched is therefore of importance.We propose a method for dynamic reconfiguration of networks using up*/down* routing that aims at reducing the consequences of reconfiguration. Identifying a restricted part of the network, the skyline, as the only part where a full reconfiguration is necessary, does this. This means that most of the network does not need to take part in the reconfiguration at all (other than adding entries for new nodes, and removing entries for removed nodes).Experiments show that for the most frequent configuration changes the skyline will be empty in 85-95% of the cases, leaving the whole of the network operational through the entire reconfiguration. For the most dramatic changes in topology - the addition of a link connecting two previously disjoint networks - an average of 90% of the links can start using the new routing function immediately for some topologies. Our approach is in principle orthogonal to other approaches, thus existing methods for dynamic reconfiguration can be applied in the reconfiguration of the skyline.
Efficiently Irreducible Bases in Multiple-Valued Logic
Authors: Grant Pogosyan
Venue: Proceedings of the 26th International Symposium on Multiple-Valued Logic (1996)

Basis is a functionally complete set of Multiple-Valued Logic functions that is irreducible, i.e. contains no complete proper subsets. Functional completeness of a set means that for any function in MVL there exists a formula over this set that implements it. However, this classical definition of basis does not consider the efficiency of implementation, particularly, it does not guarantee the existence of an efficient implementation regarding the complexity of formal expressions. In this paper the notion of efficiently irreducible basis is introduced, and is termed e-basis. A criterion for the basic set of operations to be efficiently irreducible is given. In the cases of Boolean and Ternary logic functions complete enumeration and description of e-bases are presented.
Color by Correlation: A Simple, Unifying Approach to Color Constancy
Authors: G. D. Finlayson, S. D. Hordley, P. M. Hubel
Venue: Proceedings of the International Conference on Computer Vision-Volume 2 - Volume 2 (1999)

In this paper we consider the problem of color constancy; how given an image of a scene under an unknown illuminant can we recover an estimate of that light? Rather than recovering a single estimate of the illuminant as many previous authors have done, in the first instance we recover a measure of the likelihood that each possible illuminant was the scene illuminant. We do this by correlating image colors with the colors that can occur under each of a set of possible lights. We then recover an estimate of the scene illuminant based on these likelihoods. Computation is expressed and performed in a generic correlation framework which we develop in this paper. We develop a new probabilistic instantiation of this framework which delivers very good color constancy on synthetic and real images. We show that the proposed framework is rich enough to allow many existing algorithms to be expressed within it; e.g. the grey-world and gamut mapping algorithms. We explore too the relationship of these algorithms to other probabilistic and neural network approaches.
Processor Allocation in the Star Graph Using Sg-lattice Model
Authors: Fan Wu, Ching-Chi Hsu
Venue: Proceedings of the 1997 International Symposium on Parallel Architectures, Algorithms and Networks (1997)

The star graph has been known as an attractive alternative to the hypercube multiprocessor. When tasks arrive at the star graph, the tasks should be assigned appropriate free processors before execution. A new model, called Star graph (Sg)-lattice, is proposed to model the construction and free configuration of the star graph. Based on this model, the Sg-lattice scheme can fully recognizes the substars. Finally, mathematical analyses and simulation results show that the Sg-lattice scheme outperforms the previous work in storage and time complexities and the average allocation time. Index terms-- Allocation, star graph, first-fit, Sg-lattice, star code.
The Cart-Pole Experiment as a Benchmark for Trainable Controllers
Authors: Shlomo Geva, Joaquin Sitte
Venue:  (1992)

It is widely believed that balancing an inverted pendulum is a difficult nonlinear control task. Many researchers have used a variant of the inverted pendulum problem, the cart-pole, for demonstrating the success of their neural network learning methods. It has been known for a long time that a linear control law, implemented by a single artificial neuron, can control the cart-pole. Not noted before was that a random search in weight space can quickly uncover coefficients (weights) for controllers that work over a wide range of initial conditions. This result indicates that success in finding a satisfactory neural controller is not sufficient proof for the effectiveness of unsupervised training methods. By analysing the dynamics of the linear controller we reformulate the cart-pole problem to make it a more stringent test for neural training methods. A review of the literature on unsupervised training methods for cart-pole controllers shows that the published results are difficult to compare and that for most of the methods there is no clear evidence of better performance than the random search method.
From type inference to configuration
Authors: Morten Heine Sørensen, Jens Peter Secher
Venue: The essence of computation: complexity, analysis, transformation (2002)

A product line is a set of products and features with constraints on which subsets are available. Numerous configurators have been made available by product line vendors on the internet, in which procurers can experiment with the different options, e.g. how the selection of one product or feature entails or precludes the selection of another product or feature.We explore an approach to configuration inspired by type inference technology. The main contributions of the paper are a formalization of the configuration problem that includes aspects related to the interactive dialogue between the user and the system, a result stating that the configuration problem thus formalized has at least exponential complexity, and some techniques for computing approximate solutions more efficiently. While a substantial number of papers precede the present one in formalizing configuration as a constraint satisfaction problem, few address the aspects concerning interactivity between the user and the system.
Multimedia and Security Workshop at ACM Multimedia 98 Bristol, U.K.
Authors: bibliothek ARRAY(0x8434bbc) EMAIL::
Venue:  (1998)

In this paper we describe the most important security requirements, which must be ful-filled by today''s IT-systems, and the security measures used to satisfy these requirements. These security measures are based on modern cryptographic mechanisms as well as on security infrastructures. Regarding data security and communication security in particular in the field of multime-dia, the requirements on security increase. If and in which way the discussed security mechanisms can be applied to multimedia se-curity is difficult to analyse. This is mainly due to the complexity of multimedia data and their applications. This paper introduces the main issues of IT-security and represents the basis for solutions of security problems in the field of multimedia. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
A CORBA-Based Architecture for Integrating Distributed and Heterogeneous Databases
Authors: Xuequn Wu
Venue: Proceedings of the 5th International Conference on Engineering of Complex Computer Systems (1999)

During an industrial research project of Deutsche Telekom, we designed and developed the VHDBS1 system, a federated database system for integrating information from pre-existing and legacy database systems in a distributed and heterogeneous environment. VHDBS is based on the OMG/CORBA 2.0 that provides an interoperability infrastructure. In this paper we present some main design aspects of the architecture of the system VHDBS, including an overview of the CORBA-based architecture and the benefits of including CORBA in such an architecture, the repository concept for global schema integration, and the database adapters that serve as the plug-in mechanism of the architecture.
Emergent behavior in phonological pattern change
Authors: Mark Dras, K. David Harrison
Venue: Proceedings of the eighth international conference on Artificial life (2002)

Language change has recently come to be seen as a complex dynamical system, along the lines of evolutionary biology and economics, as opposed to previous conceptions as a linear or cyclical system. We model the change of a particular phenomenon, vowel harmony, and look at the conditions under which the trajectory of change matches theoretical and empirical predictions. Our experimental work shows that there are certain conditions under which the desired trajectories do not occur, implying that absence of these conditions is necessary for accurate modeling of language change.
Optimal Hierarchical Adaptive Mesh Construction Using FCO Sampling
Venue: Proceedings of the International Conference on Information Visualisation (2000)

This paper introduces an optimal hierarchical adaptive mesh construction algorithm using the Face-Centered Orthorhombic lattice (FCO) sampling, which is a natural extension of the quincunx lattice to the 3-dimensional case. A scheme for construction of adaptive meshes is presented. Initially, a highly detailed and densely sampled regular mesh is obtained from geometry scanning or from a non-optimal polygon mesh. The adaptive triangle mesh is constructed by using fixed position vertices along with an efficient adaptive triangulation technique. The decimation is based on FCO sampling and surface estimation filters. The result is a progressive sequence of meshes consisting of more triangles wherever sharp edges exist and fewer in uniform plane regions. Experimental results demonstrate the usage and performance of the algorithm. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Erdos and Renyi Conjecture
Authors: Saharon Shelah
Venue:  (1997)

Affirming a conjecture of P. Erdos and R\''enyi we prove that for any $c_1 < 0$ for some $c_2 < 0$, if a graph $G$ has no $c_1\ \ \log n$ nodes on which the graph is complete or edgeless (i.e. $G$ exemplifies $|G| \nrightarrow (c_1 \text{ log } n)^2_2$) \underbar{then} $G$ has at least $2^{c_2n}$ non-isomorphic (induced) subgraphs.
Partitioned Quasi-Newton Methods for Nonlinear Equality Constrained Optimization
Authors: Thomas F. Coleman, Peter Fenyes
Venue:  (1988)

We derive new quasi-Newton updates for the (nonlinear) equality constrained minimization problem. The new updates satisfy a quasi-Newton equation, maintain positive definiteness on the null space of the active constraint matrix and satisfy a minimum change condition. The application of the updates is not restricted to a small neighbourhood of the solution. In addition to derivation and motivational remarks, we discuss various numerical subtleties and provide results of numerical experiments.
A highly stable deferred correction scheme with interpolant for systems of nonlinear two-point boundary value problems
Authors: J. R. Cash, D. R. Moore, N. Sumarti, M. Van Daele
Venue: Journal of Computational and Applied Mathematics (2003)

Iterated deferred correction is a very popular approach to the numerical solution of general first-order systems of nonlinear two-point boundary value problems. Typically the order of accuracy of the solution is increased by 2 each time that a deferred correction is applied and this allows inexpensive local error estimates to be computed using embedding. Recent research has shown how deferred correction schemes having the very desirable property of superconvergence can be derived. This marks a significant step forward in the design of deferred correction algorithms although the price to be paid for superconvergence is that it is difficult to derive realistic embedded local error estimates. In the present paper we show that Richardson extrapolation is a viable alternative for error estimation and we consider in some detail the relative merits of embedding and extrapolation. Guided by this analysis we are able to derive for the first time a Lobatto deferred correction code which is very efficient for the solution of stiff problems, particularly in cases where the MIRK code TWPBVP.f is unstable. Furthermore we are able to derive efficient interpolants for this Lobatto code which are also applicable to MIRK formulae and we consider the problem of estimating the error in these interpolants. This completely solves the interpolation problem for our deferred correction codes apart perhaps for deriving interpolants for extremely stiff problems. This new Lobatto code is available on the web page of one of the present authors and fills a large gap in currently available deferred correction software.