ppxscal/embedding_network huggingface dataset:
An optimal order interior penalty discontinuous Galerkin discretization of the compressible Navier-Stokes equations
Authors: Ralf Hartmann, Paul Houston
Venue: Journal of Computational Physics (2008)

In this article we propose a new symmetric version of the interior penalty discontinuous Galerkin finite element method for the numerical approximation of the compressible Navier-Stokes equations. Here, particular emphasis is devoted to the construction of an optimal numerical method for the evaluation of certain target functionals of practical interest, such as the lift and drag coefficients of a body immersed in a viscous fluid. With this in mind, the key ingredients in the construction of the method include: (i) an adjoint consistent imposition of the boundary conditions; (ii) an adjoint consistent reformulation of the underlying target functional of practical interest; (iii) design of appropriate interior penalty stabilization terms. Numerical experiments presented within this article clearly indicate the optimality of the proposed method when the error is measured in terms of both the L"2-norm, as well as for certain target functionals. Computational comparisons with other discontinuous Galerkin schemes proposed in the literature, including the second scheme of Bassi and Rebay, cf. [F. Bassi, S. Rebay, GMRES discontinuous Galerkin solution of the compressible Navier-Stokes equations, in: B. Cockburn, G. Karniadakis, C.-W. Shu (Eds.), Discontinuous Galerkin Methods, Lecture Notes in Comput. Sci. Engrg., vol. 11, Springer, Berlin, 2000, pp. 197-208; F. Bassi, S. Rebay, Numerical evaluation of two discontinuous Galerkin methods for the compressible Navier-Stokes equations, Int. J. Numer. Methods Fluids 40 (2002) 197-207], the standard SIPG method outlined in [R. Hartmann, P. Houston, Symmetric interior penalty DG methods for the compressible Navier-Stokes equations. I: Method formulation, Int. J. Numer. Anal. Model. 3(1) (2006) 1-20], and an NIPG variant of the new scheme will be undertaken.
Hierarchical Graph Embedding for Efficient Query Processing in Very Large Traffic Networks
Authors: Hans-Peter Kriegel, Peer Kröger, Matthias Renz, Tim Schmidt
Venue: Proceedings of the 20th international conference on Scientific and Statistical Database Management (2008)

We present a novel graph embedding to speed-up distance-range and k-nearest neighbor queries on static and/or dynamic objects located on a (weighted) graph that is applicable also for very large networks. Our method extends an existing embedding called reference node embedding which can be used to compute accurate lower and upper bounding filters for the true shortest path distance. In order to solve the problem of high storage cost for the network embedding, we propose a novel concept called hierarchical embedding that scales well to very large traffic networks. Our experimental evaluation on several real-world data sets demonstrates the benefits of our proposed concepts, i.e. efficient query processing and reduced storage cost, over existing work.
Algorithms for tomographic reconstruction: fast back projection and cardiac computed tomography
Authors: Yoram Bresler
Venue:  (2007)

This dissertation addresses two problems in tomographic reconstruction. The first problem is the reconstruction of an image from tomographic projections using a small number of computations. We present three algorithms, for the fan-beam and cone-beam tomographic geometry that reconstruct the image at a resolution comparable to conventional methods but that use less than an order-of-magnitude fewer computations in certain typical cases. The algorithms, based on our previous work for parallel-beam data, is based on the combination of two key components. The first component, based on a Fourier-domain understanding of tomography, is the ability to represent an image with a small number of samples if it is created from a small number of tomographic projections. The second component is the decomposition of the whole problem into a hierarchy of smaller subproblems to reduce its complexity. The second problem we address is that of the reconstruction of a movie of the moving heart from fan-beam tomographic projections. We consider the problem within a state-space framework and present a reconstruction algorithm based on the ensemble Kalman filter. The algorithm reconstructs a movie of the moving heart that is free of the motion artifacts of conventional methods.
Shadow Resistant Road Segmentation from a Mobile Monocular System
Authors: José Manuel Álvarez, Antonio M. López, Ramon Baldrich
Venue: Proceedings of the 3rd Iberian conference on Pattern Recognition and Image Analysis, Part II (2007)

An essential functionality for advanced driver assistance systems (ADAS) is road segmentation, which directly supports ADAS applications like road departure warning and is an invaluable background segmentation stage for other functionalities as vehicle detection. Unfortunately, road segmentation is far from being trivial since the road is in an outdoor scenario imaged from a mobile platform. For instance, shadows are a relevant problem for segmentation. The usual approaches are ad hoc mechanisms, applied after an initial segmentation step, that try to recover road patches not included as segmented road for being in shadow. In this paper we argue that by using a different feature space to perform the segmentation we can minimize the problem of shadows from the very beginning. Rather than the usual segmentation in a color space we propose segmentation in a shadowless image which is computable in real---time using a color camera. The paper presents comparative results for both asphalted and non---asphalted roads, showing the benefits of the proposal in presence of shadows and vehicles.
Mri/fmri noise reduction and data analysis
Authors: Lili He
Venue:  (2008)

The thesis addresses two critical issues in the processing of Magnetic Resonance Images (MRI) which have a wide-ranging impact in the deployment of MRI in clinical and scientific settings viz. the reduction of noise in MR images, and a subsequent noise-robust clustering process for analyzing critical aspects of functional MRI (fMRI). MR images acquired with fast acquisition techniques often display low signal-to-noise ratios (SNRs). In addition to the problem of relatively poor SNR in MR in general, fMRI often exhibit a low contrast to noise ratio (CNR). Therefore efficient MR denoising techniques and noise robust methods for detecting small and localized brain activations are critical both in clinical and in more general scientific use of MRI/fMRI. Since noise in MR magnitude images is known to be signal-dependent Rician distributed, standard approaches, which assume Gaussian noise model, are at best sub-optimal and at worst significantly in error. In this thesis, we develop a novel Non-Local Maximum Likelihood Estimation (NLML) method for Rician noise reduction in MRI/fMRI. We assume that the underpinning noise is in fact Rician, and posit that pixels which have similar neighborhoods come from the same distribution. By comparing NLML to a wide variety of standard denoising approaches, we show that it outperforms most traditional smoothing algorithms, non-local means and wavelet-based algorithms in recovering the true signal from Rician noise in terms of: SNR, contrast, the preservation of sharp tissue boundaries in terms of visual appearance, method error and a well-defined sharpness metric. In addition, in order to improve the accuracy of the detection of brain activation regions in fMRI, we develop a novel noise-robust Spatial Fuzzy Clustering (SFC) algorithm, which incorporates spatial regularization by means of a Markov Random Field (MRF) model. We assume that fMRI Statistical Parametric Map (SPM) to be best modeled by an MRF and couple the MRF to the fuzzy model by defining a fuzzy neighborhood energy function that describes the interaction between neighboring voxels. By comparing the clustering performance of our method to extant brain activation clustering strategies, we demonstrate that the SFC algorithm outperforms standard approaches, both on simulated and actual data. 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
Incorporating Engineering Formalisms into Automated Model Builders
Authors: Matthew Easley, Elizabeth Bradley
Venue: Computational Discovery of Scientific Knowledge: Introduction, Techniques, and Applications in Environmental and Life Sciences (2007)

We present a new knowledge representation and reasoning framework for modeling nonlinear dynamic systems. The goals of this framework are to smoothly incorporate varying levels of domain knowledge and to tailor the search space and the reasoning methods accordingly. In particular, we introduce a new structure for automated model building known as a meta-domain which, when instantiated with domain-specific components, tailors the space of candidate models to the system at hand. We combine this abstract modeling paradigm with ideas from generalized physical networks, a meta-level representation of idealized two-terminal elements, and a hierarchy of qualitative and quantitative analysis tools, to produce dynamic modeling domains whose complexity naturally adapts to the amount of available information about the target system. Since the domain and meta-domain representation use the same type of techniques and formalisms as practicing engineers, the models produced from these frameworks are naturally communicable to their target audience.
Embedded Software Architecture for Diagnosing Network and Node Failures in Wireless Sensor Networks
Authors: Jukka Suhonen, Mikko Kohvakka, Marko Hännikäinen, Timo D. Hämäläinen
Venue: Proceedings of the 8th international workshop on Embedded Computer Systems: Architectures, Modeling, and Simulation (2008)

Wireless Sensor Networks (WSNs) consist of embedded and distributed sensor nodes that operate on harsh operating conditions and with limited energy resources. To ensure the desired level of service, it is essential to detect and correct occurring network and node problems. In this paper, we propose a diagnostics software architecture for WSNs consisting of self-diagnostics on embedded sensor nodes and management tools for network analysis. We define a minimum set of diagnostics information that needs to be collected for analyzing the network errors and performance. To minimize communication overhead, collected information is categorized and only needed categories are requested from nodes. The diagnostics architecture is verified with a practical WSN implementation.
Polygon-Based Similarity Aggregation for Ontology Matching
Authors: Feiyu Lin, Kurt Sandkuhl
Venue: Proceedings of the SSDSN, UPWN, WISH, SGC, ParDMCom, HiPCoMB, and IST-AWSN international workshops held at ISPA 2007 on Frontiers of High Performance Computing and Networking (2007)

Due to an increased awareness of potential ontology applications in industry, public administration and academia, a growing number of ontologies are created by different organizations and individuals. Although these ontologies are developed for various application purposes and areas, they often contain overlapping information. In this context, it is necessary to find ways to integrate various ontologies and enable use of multiple ontologies. In this paper, we extend previous work on ontology matching using polygon-based similarity aggregation. The main ideas we contribute to the research field are (1) an improved approach to aggregate the results of distance calculations between concepts in different ontologies by creating polygons for each ontology and (2) to compare the area of these polygons for deciding on similarity.
The Effect of Recording Reference on EEG: Phase Synchrony and Coherence
Authors: Sanqing Hu, Matt Stead, Andrew B. Gardner, Gregory A. Worrell
Venue: Proceedings of the 4th international symposium on Neural Networks: Part II--Advances in Neural Networks (2007)

In [1], we developed two methods to automatically identify the contribution of the recording reference signal from multi-channel intracranial Electroencephalography (iEEG) recordings. In this study, we subtract the reference recording contribution to iEEG and obtain corrected iEEG. We then investigate three commonly used iEEG metrics: spectral power, phase synchrony, and magnitude squared coherence (MSC) for common referential iEEG, corrected iEEG and bipolar montage iEEG. We find significant differences among the three iEEG metrics, and are able to determine the contribution from the recording reference to each metric. Generally, reference signals with smaller amplitude yield lower phase synchrony and reference signals with larger amplitude increase phase synchrony. Reference signals with spectral peaks increase coherence. Reference signal with low power may have no significant impact on calculated coherence. Bipolar EEG usually yields small phase synchrony or MSC values and may obscure the actual phase synchrony or MSC values between two local sources.
A class of ninth degree system with four isochronous centers
Authors: Chaoxiong Du, Yirong Liu, Heilong Mi
Venue: Computers Mathematics with Applications (2008)

In this paper we study a class of ninth degree system and obtain the conditions that its four singular points can be general centers and isochronous centers (or linearizable centers) at the same time by computing carefully and strict proof. What is worth mentioning is that the expressions of Liapunov constants and periodic constants are simpler, and recursive formulas of node point values are given for the first time, which is a new effective criterion for verifying isochronous centers.
Machine intelligence quotient: a multiple perspective analysis of intelligent artificial systems including educational technology
Authors: Marilyn K. Simon
Venue:  (2008)

Many of the problems that machine intelligence (MI) is expected to solve require extensive knowledge about the world. In order to make informed decisions regarding MI, computing and policy professionals need to understand how to measure intelligent machines. Multiple perspectives (TOP), machine intelligence measurement (MIM), and fuzzy set theories were used to determine the commonalities and differences among the current diverse machine intelligence quotient (MIQ) theories and the means to synthesize them. Three perspectives of MIM were synthesized: the technical perspective (T) focused on features that are of no qualitative meaning to humans; the organizational perspective (O) focused on whether a machine violated any regulation during the course of the intelligent actions; and the personal perspective (P) focused on subtle features parallel to human intelligence. An analysis of 185 scholarly articles on MIQ, suggested that autonomy-theoretic, information-theoretic, performance-theoretic, and semiotic-theoretic measures were in accord with the T-perspective; and the Turing, Searle, and phenomenology tests were in accord with the P perspective. No measure was discovered with the O perspective. An MIQ calculus based on the theoretic framework and three scientific contexts in which a machine could be tested was created. Linguistic Choquet fuzzy integral and complex fuzzy set were used to analyze a case data to demonstrate the calculus. Recommendation was made to use TOP to measure the intelligence of machines. The MIQ tools suggested by this study can be used by computing professionals to measure and make informed decisions on MI.
A Construction Method of Moore Neighborhood Number-Conserving Cellular Automata
Authors: Naonori Tanimoto, Katsunobu Imai
Venue: Proceedings of the 8th international conference on Cellular Automata for Reseach and Industry (2008)

A number-conserving cellular automaton (NCCA) is a cellular automaton such that all states of cells are represented by integers and the total of the numbers (states) of all cells of a global configuration is conserved throughout its computing process. It can be thought to be a kind of modelization of the physical conservation law of mass or energy. In this paper, we show a sufficient condition for a Moore neighborhood CA to be number-conserving. According to this condition, the local function of rotation-symmetric NCCA is expressed by a summation of quaternary functions. On this framework, we construct a 6-state logically universal NCCA.
A Case-Based Approach to Anomaly Intrusion Detection
Authors: Alessandro Micarelli, Giuseppe Sansonetti
Venue: Proceedings of the 5th international conference on Machine Learning and Data Mining in Pattern Recognition (2007)

The architecture herein advanced finds its rationale in the visual interpretation of data obtained from monitoring computers and computer networks with the objective of detecting security violations. This new outlook on the problem may offer new and unprecedented techniques for intrusion detection which take advantage of algorithmic tools drawn from the realm of image processing and computer vision. In the system we propose, the normal interaction between users and network configuration is represented in the form of snapshots that refer to a limited number of attack-free instances of different applications. Based on the representations generated in this way, a library is built which is managed according to a case-based approach. The comparison between the query snapshot and those recorded in the system database is performed by computing the Earth Mover's Distance between the corresponding feature distributions obtained through cluster analysis.
Calculation of the Potential Distribution Area of the Target in Bi-station Bearing-Crossing Locating
Authors: Faxing Lu, Ling Wu
Venue: Proceedings of the 2008 Congress on Image and Signal Processing, Vol. 5 - Volume 05 (2008)

In evaluation of the capture probability of the anti-ship missile (ASM) and the probability of the target in the launching envelope of the missile, the potential distribution area of the target should be taken into account, which is determined by the errors in locating the target. But the calculation equations of the distribution area are always too complex to use in practice where they may slow down the reaction of the missiles. The paper presents equivalent equations for the calculation of the probability density function (PDF) of the target location error in bi-station bearing-crossing locating, based on the characteristics of the potential distribution area of the target. The equivalent has simple form and is easy for calculating, which gains for the ASM fast reaction speed and improvement of its effectiveness in operational uses. The validity of the equivalent is verified in simulations.
Interface and interaction design for one-handed mobile computing
Authors: Benjamin B. Bederson
Venue:  (2007)

Mobile phones are not only a ubiquitous social accessory, but rapid technology advances have transformed them into feature-rich, Internet-enabled mobile PCs&mdash;a role once reserved for touchscreen-based personal digital assistants (PDAs). Although the most widespread phone styles in circulation feature the classic combination of numeric keypad and non-touchscreen display, larger touchscreen devices are gaining ground, as indicated by the fervor surrounding new devices such as Apple's iPhone and LG's Prada phone. Yet as devices evolve, users will remain constrained by the limits of their own visual, physical, and mental resources. My research has focused on the specific limitation that mobile users often have only one hand available to operate a device, which can be especially problematic for touchscreen-based devices, since they are frequently designed for two-handed stylus operation. Considering the growing volumes of data that small devices can now store and connect to, as well as the expanding cultural role of mobile phones, improving usability in mobile computing has potentially enormous implications for user productivity, satisfaction and even safety.My own exploratory surveys have suggested that one-handed use of mobile devices is very common but that today's hardware and software designs do not support users in performing many tasks with only one hand. Motivated by these findings, the research goal of this dissertation is to contribute substantial knowledge in the form of empirically backed design guidelines and interaction techniques for improving one-handed usability and operation of mobile devices, with particular emphasis on those with touch-sensitive displays. The guidelines for one-handed mobile device design are the product of a series of studies conducted in pursuit of foundational knowledge in user behavior, preference, thumb capabilities and touchscreen-thumb interaction characteristics for single-handed device use. I also demonstrate the application of these guidelines through the development and evaluation of four applications. Two involve designs for navigating among programs, one provides an interface for searching large data sets, and the last offers a generalized mechanism for controlling arbitrary touchscreen interfaces with a thumb. Each of these applications explores a different one-handed interaction technique and offers perspective on its viability for one-handed device use.
Relationship between Two Approaches for Defining the Standard Model PA-ness
Authors: Isamu Teranishi, Wakaha Ogata
Venue: Proceedings of the 13th Australasian conference on Information Security and Privacy (2008)

There are two approaches to define Plaintext Awareness (PA). The first one is a classical approach to define the PA security and is used to define the PA security of the random oracle model. This approach enables us to define the PA-ness simply, but no one know whether we can define the standard model PA security based on this approach. In contrast, the second approach is a current approach to define the PA security. It enables us to define the standard model PA security formally, but it is more elaborate than the overwhelming-based approach. In this paper, we aim to clarify relations between the two approaches. We define the standard model PA security based on the first approach. Then we show that, under a very weak condition, it is equivalent to the known definition of the standard model PA security based on the second approach.
Monte-Carlo Tree Search Solver
Authors: Mark H. Winands, Yngvi Björnsson, Jahn-Takeshi Saito
Venue: Proceedings of the 6th international conference on Computers and Games (2008)

Recently, Monte-Carlo Tree Search (MCTS) has advanced the field of computer Go substantially. In this article we investigate the application of MCTS for the game Lines of Action (LOA). A new MCTS variant, called MCTS-Solver, has been designed to play narrow tactical lines better in sudden-death games such as LOA. The variant differs from the traditional MCTS in respect to backpropagation and selection strategy. It is able to prove the game-theoretical value of a position given sufficient time. Experiments show that a Monte-Carlo LOA program using MCTS-Solver defeats a program using MCTS by a winning score of 65%. Moreover, MCTS-Solver performs much better than a program using MCTS against several different versions of the world-class ¿β program MIA. Thus, MCTS-Solver constitutes genuine progress in using simulation-based search approaches in sudden-death games, significantly improving upon MCTS-based programs.