ppxscal/embedding_network huggingface dataset:
Dynamic Control with Indistinguishable Events
Authors: X. Briand
Venue: Discrete Event Dynamic Systems (2006)

We consider the problem of synthesizing controllers for dicrete event systems with indistinguishable events. The specification for the supervised system as well as the constraints for the controllers are defined by an extension of the logic of the ¿-calculus that generalize the framework introduced by Ramadge and Wonham. More precisely, in order to express that some events are indistinguishable, one can specify with this extension that, from a node of a graph, two edges reach the same node. As for the ¿-calculus, the model cheking problem and also the emptiness problem for this extension amount to computing winning strategies in parity games. We show that the centralized control problem with indistinguishable events is decidable by reducing it to the satisfiability problem of a formula of this extension of the ¿-calculus. We prove also that, unfortunately, the decentralized control problem is undecidable by a reduction of the halting problem of a Turing machine. Moreover, we exhibit a decidable case of decentralized control by restricting the specifications to those which we called here "conic".
Emotion and Attention Interaction Studied through Event-Related Potentials
Authors: Luis Carretié, Manuel Martín-loeches, José Antonio Hinojosa, Francisco Mercado
Venue: Journal of Cognitive Neuroscience (2001)

Several studies on hemodynamic brain activity indicate that emotional visual stimuli elicit greater activation than neutral stimuli in attention-related areas such as the anterior cingulate cortex (ACC) and the visual association cortex (VAC). In order to explore the temporo-spatial characteristics of the interaction between attention and emotion, two processes characterized by involving short and rapid phases, event-related potentials (ERPs) were measured in 29 subjects using a 60-electrode array and the LORETA source localization software. A cue/target paradigm was employed in order to investigate both expectancy-related and input processing-related attention. Four categories of stimuli were presented to subjects: positive arousing, negative arousing, relaxing, and neutral. Three attention-related components were finally analyzed: N280pre (from pretarget ERPs), P200post and P340post (both from posttarget ERPs). N280pre had a prefrontal focus (ACC and/or medial prefrontal cortex) and presented significantly lower amplitudes in response to cues announcing negative targets. This result suggests a greater capacity of nonaversive stimuli to generate expectancy-related attention. P200post and P340post were both elicited in the VAC, and showed their highest amplitudes in response to negative- and to positive-arousing stimuli, respectively. The origin of P200post appears to be located dorsally with respect to the clear ventral-stream origin of P340post. The conjunction of temporal and spatial characteristics of P200post and P340post leads to the deduction that input processing-related attention associated with emotional visual stimulation involves an initial, rapid, and brief 'early' attentional response oriented to rapid motor action, being more prominent towards negative stimulation. This is followed by a slower but longer 'late' attentional response oriented to deeper processing, elicited to a greater extent by appetitive stimulation.
Numerical Study of a Modified Time-Stepping θ-Scheme for Incompressible Flow Simulations
Authors: Stefan Turek, Ludmila Rivkind, Jaroslav Hron, Roland Glowinski
Venue: Journal of Scientific Computing (2006)

In [Turek (1996). Int. J. Numer. Meth. Fluids 22, 987---1011], we had performed numerical comparisons for different time stepping schemes for the incompressible Navier---Stokes equations. In this paper, we present the numerical analysis in the context of the Navier---Stokes equations for a modified time-stepping ¿-scheme which has been recently proposed by Glowinski [Glowinski (2003). In: Ciarlet, P. G., and Lions, J. L. (eds.), Handbook of Numerical Analysis, Vol. IX, North-Holland, Amsterdam, pp. 3---1176]. Like the well-known classical Fractional-Step-¿-scheme which had been introduced by Glowinski [Glowinski (1985). In Murman, E. M. and Abarbanel, S. S. (eds.), Progress and Supercomputing in Computational Fluid Dynamics, Birkhäuser, Boston MA; Bristeau et al. (1987). Comput. Phys. Rep. 6, 73---187], too, and which is still one of the most popular time stepping schemes, with or without operator splitting techniques, this new scheme consists of 3 substeps with nonequidistant substepping to build one macro time step. However, in contrast to the Fractional-Step-¿-scheme, the second substep can be formulated as an extrapolation step for previously computed data only, and the two remaining substeps look like a Backward Euler step so that no expensive operator evaluations for the right hand side vector with older solutions, as for instance in the Crank---Nicolson scheme, have to be performed. This modified scheme is implicit, strongly A-stable and second order accurate, too, which promises some advantageous behavior, particularly in implicit CFD simulations for the nonstationary Navier---Stokes equations. Representative numerical results, based on the software package FEATFLOW [Turek (2000). FEATFLOW Finite element software for the incompressible Navier---Stokes equations: User Manual, Release 1.2, University of Dortmund] are obtained for typical flow problems with benchmark character which provide a fair rating of the solution schemes, particularly in long time simulations.
Malafide Intension and its mapping to Privacy Policy Purposes for Masquerading
Authors: Vikram Goyal, Shyam K. Gupta, Anand Gupta
Venue: Proceedings of the 10th International Database Engineering and Applications Symposium (2006)

In presence of a robust privacy infrastructure, an attacker can fulfill his purpose(malafide intension) only by masquerading it with bonafide purposes besides other authentication parameters. We address the issue of masquerading of purpose for a malafide intension by defining the mapping from a malafide intension to bonafide purposes in this paper. An understanding of such a mapping can facilitate both a hacker (assist him in masquerading) and a forensic expert to investigate malafide accesses. Determination of these bonafide purposes may help speed up the violation detection if the User Accesses Log has listed bonafide purpose with each user access. The bonafide purposes can be determined in data-independent (without accessing the database) or data-dependent (database access is required) mode. In this paper we define a mapping of a malafide intension to bonafide purposes in dataindependent mode.
Low rate convolutional and turbo codes based on non-linear cyclic codes: Research Articles
Authors: Nuno Souto, João Carlos Silva, Francisco Cercas, Américo Correia, António Rodrigues
Venue: Wireless Communications Mobile Computing (2007)

Low rate convolutional and turbo codes that output non-linear cyclic (NLC) codewords of length n&thinsp;=&thinsp;2m, m being a positive integer, are described. These codes have a very low coding rate, which makes them especially suitable for spread spectrum systems where they can be used for simultaneously achieving error correction and bandwidth expansion. Due to the cyclic properties and codeword length of the component codes, branch metrics can be efficiently computed using the fast Fourier transform (FFT), enabling simple implementation of the encoder and decoder. Among the possible NLC base codes, special attention is given to the Tomlinson, Cercas, Hughes (TCH) codes family due to their good autocorrelation properties. It is shown by simulation that the turbo codes schemes studied usually perform better than traditional turbo codes (in this paper the universal mobile telecommunications system (UMTS), rate 1&#x002F;3 turbo code was used as a reference). This improvement is accomplished at the cost of bandwidth expansion. One of the advantages of the presented solutions over other low rate codes is their ability to improve the synchronization process at the receiver due to the good autocorrelation properties of the available NLC codes (especially TCH codes). A comparison of performance between the UMTS uplink connection and an equivalent system using the proposed codes for a multiuser scenario in a multipath fading channel is presented showing the possibility of capacity increase when using these codes. Copyright &copy; 2006 John Wiley & Sons, Ltd.
Proceedings of the international workshop on Storage network architecture and parallel I/Os
Venue: Storage Network Architecture And Parallel I/Os (2003)

I would like to welcome all attendees for coming to this workshop. In particular, I would like to thank the authors for submitting their research work to the workshop and to share their ideas and technical contributions with us today.Over the past 50 years, computer architects have put forth tremendous amount of efforts in improving performance/cost of CPUs. As a result, we enjoy greatly today the success of such efforts that have changed completely our life. At the same time, the speed gap between CPU and data storage has increased dramatically to several orders of magnitudes making data storage become the major bottle-neck of a computing system and hence a critical area to be worked on for further development of computer technology. Moreover, Data are the "life-blood" of computing and the main asset of any organization. As a result, data storage is playing a central role in today's fast growing networked information services as demonstrated by the fact that storage accounts for 50% of total IT spending of any organization in 2001 increased from 37% in 1998. It is predicted to be 75% of total IT spending in year 2003 while servers account for only 25%. Therefore, disk I/O and data storage on which data reside are becoming "first class citizens" in today's information world. SNAPI 03 focuses specifically on storage network architecture and parallel I/Os. Although our call for papers went out very late, we got very good responses and reasonable amount of submissions (16). Each submitted paper was reviewed by at least two reviewers with one or more of the reviewers being program committee members. We finally selected 9 high quality papers to be presented in this workshop. The decisions were based on the perceived quality, originality, and appropriateness to the theme of the workshop. The mix of selected papers reflects the unique nature of the workshop in bringing together researchers and practitioners from academia and industry to discuss cutting edge research on parallel and distributed data storage technologies. 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
Tensor-CUR decompositions for tensor-based data
Authors: Michael W. Mahoney, Mauro Maggioni, Petros Drineas
Venue: Proceedings of the 12th ACM SIGKDD international conference on Knowledge discovery and data mining (2006)

Motivated by numerous applications in which the data may be modeled by a variable subscripted by three or more indices, we develop a tensor-based extension of the matrix CUR decomposition. The tensor-CUR decomposition is most relevant as a data analysis tool when the data consist of one mode that is qualitatively different than the others. In this case, the tensor-CUR decomposition approximately expresses the original data tensor in terms of a basis consisting of underlying subtensors that are actual data elements and thus that have natural interpretation in terms ofthe processes generating the data. In order to demonstrate the general applicability of this tensor decomposition, we apply it to problems in two diverse domains of data analysis: hyperspectral medical image analysis and consumer recommendation system analysis. In the hyperspectral data application, the tensor-CUR decomposition is used to compress the data, and we show that classification quality is not substantially reduced even after substantial data compression. In the recommendation system application, the tensor-CUR decomposition is used to reconstruct missing entries in a user-product-product preference tensor, and we show that high quality recommendations can be made on the basis of a small number of basis users and a small number of product-product comparisons from a new user.
Banyan-based Architecture for Quasi-Circuit Switching
Authors: Yuh-Ren Tsai, Che-Wei Lo
Venue: Proceedings of the International conference on Networking and Services (2006)

Load balanced Birkoff-von Neumann quasi-circuit switching was proposed to control the packet delay, as well as to solve the head-of-line blocking problem. Quasi-circuit switching, a frame based scheme, is proposed to provides guaranteed rate services. However, as the switch dimension increases, the maximum delay and the size of the one-cycle permutation matrices increase accordingly. In this work, a new architecture - Banyan-based quasi-circuit switching is proposed. A large dimension switch is decomposed into multiple 2..2 frame-based switching elements in order to reduce the implementation complexity. According to the numerical and simulation results, it was found that the performance of the Banyan-based architecture is better than that of the load-balanced architecture. Especially, the standard deviation of the average packet delay can be greatly reduced by applying the proposed architecture. Therefore, the overall packet delay in a network can be well controlled and predicted.
A simulation based approach for incorporating virtual components IP cores into multimedia systems design
Authors: A. Beganne, I. Bennour, M. Elmarzougui, E. Martin
Venue: Proceedings of the 2003 International Conference on Multimedia and Expo - Volume 1 (2003)

Growing requirements on the correct design of high performance multimedia systems in a short time force us to use IP's blocks in many designs. However, their correct integration in a design implies more complex verification problems. In this paper, we present a C++/systemC based simulation flow at multiple levels of abstraction. Our approach is to use systemC to describe both application and a set of algorithmic IP cores to be incorporated throughout the design flow. Our methodology supports design refinement through four main abstraction levels, offers verification techniques at each level and allows the use of EDA co-verification tools. The use of C++/systemC to model all parts of the system provides great flexibility and enables faster simulation compared to existing methodologies. An illustrative case study for wavelet based compression system design shows that our methodology supports efficient algorithmic specification, where IP models can be easily incorporated, modified and simulated in order to quickly evaluate alternative system implementation.
Parallel Cortico-Basal Ganglia Mechanisms for Acquisition and Execution of Visuomotor Sequences - A Computational Approach
Authors: Hiroyuki Nakahara, Kenji Doya, Okihide Hikosaka
Venue: Journal of Cognitive Neuroscience (2001)

Experimental studies have suggested that many brain areas, including the basal ganglia (BG), contribute to procedural learning. Focusing on the basal ganglia-thalamocortical (BG-TC) system, we propose a computational model to explain how different brain areas work together in procedural learning. The BG-TC system is composed of multiple separate loop circuits. According to our model, two separate BG-TC loops learn a visuomotor sequence concurrently but using different coordinates, one visual, and the other motor. The visual loop includes the dorsolateral prefrontal (DLPF) cortex and the anterior part of the BG, while the motor loop includes the supplementary motor area (SMA) and the posterior BG. The concurrent learning in these loops is based on reinforcement signals carried by dopaminergic (DA) neurons that project divergently to the anterior ("visual") and posterior ("motor") parts of the striatum. It is expected, however, that the visual loop learns a sequence faster than the motor loop due to their different coordinates. The difference in learning speed may lead to inconsistent outputs from the visual and motor loops, and this problem is solved by a mechanism called a "coordinator," which adjusts the contribution of the visual and motor loops to a final motor output. The coordinator is assumed to be in the presupplementary motor area (pre-SMA). We hypothesize that the visual and motor loops, with the help of the coordinator, achieve both the quick acquisition of novel sequences and the robust execution of well-learned sequences. A computational model based on the hypothesis is examined in a series of computer simulations, referring to the results of the 2 &times; 5 task experiments that have been used on both monkeys and humans. We found that the dual mechanism with the coordinator was superior to the single (visual or motor) mechanism. The model replicated the following essential features of the experimental results: (1) the time course of learning, (2) the effect of opposite hand use, (3) the effect of sequence reversal, and (4) the effects of localized brain inactivations. Our model may account for a common feature of procedural learning: A spatial sequence of discrete actions (subserved by the visual loop) is gradually replaced by a robust motor skill (subserved by the motor loop).
Algebraic topology and concurrency
Authors: Lisbeth Fajstrup, Martin Raußen, Eric Goubault
Venue: Theoretical Computer Science (2006)

We show in this article that some concepts from homotopy theory, in algebraic topology, are relevant for studying concurrent programs. We exhibit a natural semantics of semaphore programs, based on partially ordered topological spaces, which are studied up to "elastic deformation" or homotopy, giving information about important properties of the program, such as deadlocks, unreachables, serializability, essential schedules, etc. In fact, it is not quite ordinary homotopy that has to be used, but rather a "directed homotopy" that does not reverse the flow of time. We show some of the essential differences between ordinary and directed homotopy through examples. We also relate the topological view to a combinatorial view of concurrent programs closer to transition systems, through the notion of a cubical set. Finally we apply some of these concepts to the proof of the safeness of a two-phase protocol, well-known and used in concurrent database theory. We end up with a list of problems from both a mathematical and a computer-scientific point of view.
3D Facial Model Synthesis using Voronoi Approach
Authors: Yuan Luo, Marina L. Gavrilova
Venue: Proceedings of the 3rd International Symposium on Voronoi Diagrams in Science and Engineering (2006)

Construction and animation of realistic human facial models is an important research field of computer graphics. How to efficiently create an individualized facial model for animation is still a challenge. In this papel; we present a method for 3D facial model synthesis that combines the traditional free-form deformation (FFD) model with techniques of data interpolation based on Dirichlet/Voronoi diagrams. With 18 feature points extracted from 2D facial images in two orthogonal views, Dirichlet Free Form Deformation (DFFD) is utilized for modifying a generic 3D face to produce the individual face. The main advantages of this method over former extensions of FFD is in removing the constraints on control lattice and control points location. In addition, by assigning different weights to those control points, we improve the DFFD algorithm to make it more adaptable to the facial deformation. The reconstructed 3D faces can be used to generate different facial animations.
Modeling and Analyzing Peer-to-Peer File-Sharing System
Authors: Jun Li, Shunyi Zhang
Venue: Proceedings of the 2006 IEEE/WIC/ACM international conference on Web Intelligence and Intelligent Agent Technology (2006)

Peer-to-Peer (P2P) file-sharing accounts for an astonishing volume of current Internet traffic. Therefore, modeling and analyzing P2P file-sharing system to increase its understanding is significant and instrumental for the design and evaluation of new systems. In this paper, we firstly characterize and categorize the different types of P2P architecture. Secondly, we develop an analytic model for evaluating the performance of P2P file-sharing application in terms of user-perceived QoS and impact on the underlying physical networks. Thirdly, the tradeoff between the two most important metrics is weighed and some crucial parameters are abstracted and analyzed. Lastly, the locality-awareness to save potential bandwidth is presented and analyzed as well.
Analyzing losses from hazard exposure: a conservative probabilistic estimate using supply chain risk simulation
Authors: Léa A. Deleris, Debra Elkins, M. Elisabeth Paté-Cornell
Venue: Proceedings of the 36th conference on Winter simulation (2004)

We present a supply chain risk analysis that is based on a Monte Carlo simulation of a Generalized Semi-Markov Process (G.S.M.P.) model. Specifically, we seek to estimate the probability distribution of supply chain losses caused by disruptions. This distribution is computed conditional on conservative hypotheses which are the following: (1) no additional risk reduction measures are implemented beyond those already in place, (2) all the products whose production has been canceled are counted as losses at their market value. The simulation thus yields conditional probabilities of loss levels that firms may reasonably use in the evaluation of business interruption costs and insurance coverage limits. The model also enables the comparison of supply chain designs based on their resilience in recovering from risk events. The approach is novel for it connects stochastic modeling of risks from an insurance perspective with supply chain network design.
Symbolic computation of Fenchel conjugates
Authors: Heinz H. Bauschke, Martin v. Mohrenschildt
Venue: ACM Communications in Computer Algebra (2006)

Convex optimization deals with certain classes of mathematical optimization problems including least-squares and linear programming problems. This area has recently been the focus of considerable study and interest due to the facts that convex optimization problems can be solved efficiently by interior-point methods and that convex optimization problems are actually much more prevalent in practice that previously thought.Key notions in convex optimization are the Fenchel conjugate and the subdifferential of a convex function. In this paper, we build a new bridge between convex optimization and symbolic mathematics by describing the Maple package fenchel, which allows for the symbolic computation of these objects for numerous convex functions defined on the real line. We are able to symbolically reproduce computations for finding Fenchel conjugates and subdifferentials for numerous nontrivial examples found in the literature.