ppxscal/embedding_network huggingface dataset:
Empirical mode decomposition of field potentials from macaque V4 in visual spatial attention
Authors: H. Liang, S. L. Bressler, E. A. Buffalo, R. Desimone, P. Fries
Venue: Biological Cybernetics (2005)

Empirical mode decomposition (EMD) has recently been introduced as a local and fully data-driven technique for the analysis of non-stationary time-series. It allows the frequency and amplitude of a time-series to be evaluated with excellent time resolution. In this article we consider the application of EMD to the analysis of neuronal activity in visual cortical area V4 of a macaque monkey performing a visual spatial attention task. We show that, by virtue of EMD, field potentials can be resolved into a sum of intrinsic components with different degrees of oscillatory content. Low-frequency components in single-trial recordings contribute to the average visual evoked potential (AVEP), whereas high-frequency components do not, but are identified as gamma-band (30&#x2013;90 Hz) oscillations. The magnitude of time-varying gamma activity is shown to be enhanced when the monkey attends to a visual stimulus as compared to when it is not attending to the same stimulus. Comparison with Fourier analysis shows that EMD may offer better temporal and frequency resolution. These results support the idea that the magnitude of gamma activity reflects the modulation of V4 neurons by visual spatial attention. EMD, coupled with instantaneous frequency analysis, is demonstrated to be a useful technique for the analysis of neurobiological time-series.
CrimeNet explorer: a framework for criminal network knowledge discovery
Authors: Jennifer J. Xu, Hsinchun Chen
Venue: ACM Transactions on Information Systems (TOIS) (2005)

Knowledge about the structure and organization of criminal networks is important for both crime investigation and the development of effective strategies to prevent crimes. However, except for network visualization, criminal network analysis remains primarily a manual process. Existing tools do not provide advanced structural analysis techniques that allow extraction of network knowledge from large volumes of criminal-justice data. To help law enforcement and intelligence agencies discover criminal network knowledge efficiently and effectively, in this research we proposed a framework for automated network analysis and visualization. The framework included four stages: network creation, network partition, structural analysis, and network visualization. Based upon it, we have developed a system called CrimeNet Explorer that incorporates several advanced techniques: a concept space approach, hierarchical clustering, social network analysis methods, and multidimensional scaling. Results from controlled experiments involving student subjects demonstrated that our system could achieve higher clustering recall and precision than did untrained subjects when detecting subgroups from criminal networks. Moreover, subjects identified central members and interaction patterns between groups significantly faster with the help of structural analysis functionality than with only visualization functionality. No significant gain in effectiveness was present, however. Our domain experts also reported that they believed CrimeNet Explorer could be very useful in crime investigation.
Multimodal Face Recognition: Combination of Geometry with Physiological Information
Authors: I. A. Kakadiaris, G. Passalis, T. Theoharis, G. Toderici, I. Konstantinidis, N. Murtuza
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 2 - Volume 02 (2005)

It is becoming increasingly important to be able to credential and identify authorized personnel at key points of entry. Such identity management systems commonly employ biometric identifiers. In this paper, we present a novel multimodal facial recognition approach that employs data from both visible spectrum and thermal infrared sensors. Data from multiple cameras is used to construct a three-dimensional mesh representing the face and a facial thermal texture map. An annotated face model with explicit two-dimensional parameterization (UV) is then fitted to this data to construct: 1) a three-channel UV deformation image encoding geometry, and 2) a one-channel UV vasculature image encoding facial vasculature. Recognition is accomplished by comparing: 1) the parametric deformation images, 2) the parametric vasculature images, and 3) the visible spectrum texture maps. The novelty of our work lies in the use of deformation images and physiological information as means for comparison. We have performed extensive tests on the Face Recognition Grand Challenge v1.0 dataset and on our own multimodal database with very encouraging results.
A Nonlinear Image Restoration Framework Using Vector Quantization
Authors: Edmund Y. Lam
Venue: Proceedings of the Third International Conference on Image and Graphics (2004)

Vector quantization (VQ) is a powerful method used primarily in signal and image compression. In recent years, it has also been applied to various other image processing tasks, including image classification, histogrammodification, and restoration. In this paper, we focus our attention on image restoration using VQ. We present a general framework that incorporates two other methods in the literature, and discuss our method that follows more naturally from this framework. With appropriate training data for the VQ codebook, this method can restore images beyond its diffraction limit.
A parallel/recursive algorithm
Authors: W. R. Gibbs
Venue: Journal of Computational Physics (2004)

An algorithm is discussed for converting a class of recursive processes to a parallel system. It is argued that this algorithm can be superior to certain methods currently found in the literature for an important subset of problems. The cases of homogeneous and non-homogeneous two term recursions are treated. The basic cost factor of the algorithm over non-parallel operations is 2 if only the final values of the sequence is needed and 4 if all elements are required. In practice, these factors can be reduced considerably. Applications to three problems (finding the eigenvalues of a tri-diagonal matrix, the solution of a radial wave equation and the solution of a tri-diagonal matrix) are discussed.
Note on the integer geometry of bitwise XOR
Authors: António Guedes de Oliveira, Diogo Oliveira e Silva
Venue: European Journal of Combinatorics (2005)

We consider the set N of non-negative integers together with a distance d defined as follows: given two integers x, y ∈ N, d(x, y) is, in binary notation, the result of performing, digit by digit, the "XOR" operation on (the binary notations of) x and y. Dawson, in Combinatorial Mathematics VIII, Geelong, 1980, Lecture Notes in Mathematics, 884 (1981) 136, considers this geometry and suggests the following construction: given k different integers x1,...,xk ∈ N, let Vi be the set of integers closer to xi than to any xj with j ≠ i, for i, j = 1,...,k. Let V = (V1,...,Vk) and X = (x1,...,xk). V is a partition of {0, 1,...,2n - 1} which, in general, does not determine X.In this paper, we characterize the convex sets of this geometry: they are exactly the line segments. Given X and the partition V determined by X, we also characterize in easy terms the ordered sets Y = (y1,...,yk) that determine the same partition V. This, in particular, extends one of the main results of Combinatorial Mathematics VIII, Geelong, 1980, Lecture Notes in Mathematics, 884 (1981) 136.
On proving the correctness of program transformations based on free theorems for higher-order polymorphic calculi
Authors: Patricia Johann
Venue: Mathematical Structures in Computer Science (2005)

A number of program transformations currently of interest can be derived from Wadler's &lsquo;free theorems&rsquo; for calculi approximating modern functional languages. Although delicate but fundamental issues arise in proving the correctness of free theorems-based program transformations, these issues have usually been left unaddressed in the correctness proofs appearing in the literature. As a result, most such proofs are incomplete, and most free theorems-based transformations are applied to programs in calculi for which they are not actually known to be correct.The purpose of this paper is three-fold. First, we raise and clarify some of the issues that must be addressed when constructing correctness proofs for free theorems-based program transformations. Second, we offer a principled approach to developing such proofs. Third, we use Pitts' recent work on parametricity and observational equivalence to show how our approach can be used to give the first proof that transformations based on the Acid Rain theorems preserve observational equivalence of programs in a polymorphic lambda calculus supporting FPC-style fixpoints and algebraic data types. Correctness of the foldr-build rule, the destroy-unfoldr rule, and the hylofusion program transformation for this calculus follows immediately. The same approach is expected to yield complete correctness proofs for free theorems-based transformations in calculi that even more closely resemble languages with which programmers are concerned in practice.
Hyperelliptic Curves with Compact Parameters
Authors: Ezra Brown, Bruce T. Myers, Jerome A. Solinas
Venue: Designs, Codes and Cryptography (2005)

We present a family of hyperelliptic curves whose Jacobians are suitable for cryptographic use, and whose parameters can be specified in a highly efficient way. This is done via complex multiplication and identity-based parameters. We also present some novel computational shortcuts for these families.
Optimal voltage allocation techniques for dynamically variable voltage processors
Authors: Woo-Cheol Kwon, Taewhan Kim
Venue: ACM Transactions on Embedded Computing Systems (TECS) (2005)

This paper presents important, new results of a study on the problem of task scheduling and voltage allocation in dynamically variable voltage processors, the purpose of which was minimization of processor energy consumption. The contributions are twofold: (1) For given multiple discrete supply voltages and tasks with arbitrary arrival-time/deadline constraints, we propose a voltage allocation technique that produces a feasible task schedule with optimal processor energy consumption. (2) We then extend the problem to include the case in which tasks have nonuniform loads (i.e.; switched) capacitances and solve it optimally. The proposed technique, called Alloc-vt, in (1) is based on the prior results in [Yao, Demers and Shenker. 1995. In Proceedings of IEEE Symposium on Foundations of Computer Science. 374--382] (which is optimal for dynamically continuously variable voltages, but not for discrete ones) and [Ishihara and Yasuura. 1998. In Proceedings of International Symposium on Low Power Electronics and Design. 197--202] (which is optimal for a single task, but not for multiple tasks), whereas the proposed technique, called Alloc-vtcap, in (2) is based on an efficient linear programming (LP) formulation. Both techniques solve the allocation problems optimally in polynomial time.
Representing hard lattices with O(n log n) bits
Authors: Miklós Ajtai
Venue: Proceedings of the thirty-seventh annual ACM symposium on Theory of computing (2005)

We present a variant of the Ajtai-Dwork public-key cryptosystem where the size of the public-key is only O(nlog n) bits and the encrypted text/clear text ratio is also O(nlog n). This is true with the assumption that all of the participants in the cryptosystem share O(n2log n) random bits which has to be picked only once and the users of the cryptosystem get them e.g. together with the software implementing the protocol. The public key is a random lattice with an nc-unique nonzero shortest vector, where the constant c>1‾2 can be picked arbitrarily close to 1‾2, and we pick the lattice according to a distribution described in the paper. We do not prove a worst-case average-case equivalence but the security of the system follows from the hardness of a randomized diophantine approximation problem related to a well-known theorem of Dirichlet.
Improved capacity bounds for wireless networks: Research Articles
Authors: Ashish Agarwal, P. R. Kumar
Venue: Wireless Communications Mobile Computing (2004)

We obtain improved upper and lower bounds on the best case and random case transport capacities of wireless networks under the Protocol Model of communication in Reference [1]. These results bracket the best case transport capacity to within a factor of $\sqrt8$ for wireless networks on a disk. This is done by identifying larger exclusion regions for receivers. The general result on exclusion regions can also be applied to arbitrary wireless footprints, including those arising from directional antennas, thus obtaining superior bounds for such technologies too. Copyright &copy; 2004 John Wiley & Sons, Ltd.
A reflective framework for discovery and interaction in heterogeneous mobile environments
Authors: Paul Grace, Gordon S. Blair, Sam Samuel
Venue: ACM SIGMOBILE Mobile Computing and Communications Review (2005)

To operate in dynamic and potentially unknown environments a mobile client must first discover the local services that match its requirements, and then interact with these services to obtain the application functionality. However, high levels of heterogeneity characterize mobile environments; that is, contrasting discovery protocols including SLP, UPnP and Jini, and different styles of service interaction paradigms e.g. Remote Procedure Call, Publish-Subscribe and agent based solutions. Therefore given this type of heterogeneity, utilizing single discovery and interaction systems is not optimal as the client will only be able to use the services available to that particular platform. Hence, in this paper we present an adaptive middleware solution to this problem. ReMMoC is a Web-Services based reflective middleware that allows mobile clients to be developed independently of both discovery and interaction mechanisms. We describe the architecture, which dynamically reconfigures to match the current service environment. Finally, we investigate the incurred performance overhead such dynamic behaviour brings to the discovery and interaction process.
Performance Analysis of the ARL Linux Networx Cluster
Authors: George Petit, Steven R. Thompson
Venue: Proceedings of the 2004 Users Group Conference (2004)

Within the past year, a 256-processor I686 Linux Cluster was installed at the Army Research Laboratory (ARL) Major Shared Resource Center (MSRC) to augment the center's current unclassified scientific application processing capabilities. The purpose of this paper is to provide a comparative analysis of wall-clock-time performance of this system and the other unclassified HPC platforms currently installed at the ARL MSRC. A suite of vendor applications currently receiving significant utilization on the ARL platforms will be used to perform this analysis. The other existing unclassified HPC platforms at ARL include: an SGI 3800 with 512 processors, an IBM SP3 with 1024 processors, and an IBM SP4 with 128 processors. The following application codes will be used: CTH, CFD++, OVERFLOW, GAMESS, COBALT, LS_DYNA and FLUENT. Each code will be run using 16, 32, 48, 64, 80, 96, 112, and 128 processors. Using these timing metrics we will analyze the appropriateness of the I686 architecture for use as a large-scale distributed computing platform for each of these scientific application codes.
Topological Rearrangements and Local Search Method for Tandem Duplication Trees
Authors: Denis Bertrand, Olivier Gascuel
Venue: IEEE/ACM Transactions on Computational Biology and Bioinformatics (TCBB) (2005)

The problem of reconstructing the duplication history of a set of tandemly repeated sequences was first introduced by Fitch [4]. Many recent studies deal with this problem, showing the validity of the unequal recombination model proposed by Fitch, describing numerous inference algorithms, and exploring the combinatorial properties of these new mathematical objects, which are duplication trees. In this paper, we deal with the topological rearrangement of these trees. Classical rearrangements used in phylogeny (NNI, SPR, TBR, ...) cannot be applied directly on duplication trees. We show that restricting the neighborhood defined by the SPR (Subtree Pruning and Regrafting) rearrangement to valid duplication trees, allows exploring the whole duplication tree space. We use these restricted rearrangements in a local search method which improves an initial tree via successive rearrangements. This method is applied to the optimization of parsimony and minimum evolution criteria. We show through simulations that this method improves all existing programs for both reconstructing the topology of the true tree and recovering its duplication events. We apply this approach to tandemly repeated human Zinc finger genes and observe that a much better duplication tree is obtained by our method than using any other program.
A study of dynamic addressing techniques in mobile ad hoc networks: Research Articles
Authors: Yuan Sun, Elizabeth M. Belding-Royer
Venue: Wireless Communications Mobile Computing (2004)

Dynamic address assignment enables nodes in mobile ad hoc networks to obtain a routable address without the need for any explicit configuration. It provides a means for nodes to communicate without any centralized infrastructure and provides a mechanism for dynamic network membership. Recently, a considerable number of dynamic addressing protocols have been proposed. While these approaches bear some similarities to each other, they also differ in some important characteristics. To understand the benefits of these different approaches, it is necessary to test the protocols in a wide range of network conditions so that their performance and suitability can be predicted. This paper studies existing solutions by categorizing and qualitatively analyzing the scalability and other performance properties of the approaches. We also introduce a new addressing approach that provides both quick and efficient unique address assignment. We then compare selected protocols through quantitative analysis based on extensive simulations. Based on the simulation results, we point out the applicability of the protocols and offer suggestions to improve protocol performance. Copyright &copy; 2004 John Wiley & Sons, Ltd.
Quasi-periodic decompositions and the Kemperman structure theorem
Authors: David J. Grynkiewicz
Venue: European Journal of Combinatorics (2005)

The Kemperman structure theorem (KST) yields a recursive description of the structure of a pair of finite subsets A and B of an Abelian group satisfying |A + B| ≤ |A| + |B| - 1. In this paper, we introduce a notion of quasi-periodic decompositions and develop their basic properties in relation to KST. This yields a fuller understanding of KST, and gives a way to more effectively use KST in practice. As an illustration, we first use these methods to (a) give conditions on finite sets A and B of an Abelian group so that there exists b ∈ B such that |A + (B \ {b})| ≥ |A| + |B| - 1, and to (b) give conditions on finite sets A, B, C1,...,Cr of an Abelian group so that there exists b ∈ B such that |A + (B \ {b})| ≥ |A| + |B| - 1 and |A + (B \ {b}) + Σi=1r Ci| ≥ |A| |B| + Σi=1r |Ci| - (r + 2) + 1. Additionally, we simplify two results of Hamidoune, by (a) giving a new and simple proof of a characterization of those finite subsets B of an Abelian group G for which |A + B| ≥ min{|G| - 1, |A| + |B|} holds for every finite subset A ⊆ G with |A| ≥ 2, and (b) giving, for a finite subset B ⊆ G for which |A + B| ≥ min{|G|, |A| + |B| - 1} holds for every finite subset A ⊆ G, a nonrecursive description of the structure of those finite subsets A ⊆ G such that |A + B| = |A| + |B| - 1.
Using C for CGI programming
Authors: Clay Dowling
Venue: Linux Journal (2005)

Your Web app doesn't have to be written in some newfangled scripting malarkey. Check out the speed when you try it in C.
Graph theory based parametric influences applied to torsional vibration analysis
Authors: T. R. Sreeram
Venue: Advances in Engineering Software (2005)

A graph-based technique to simulate and analyze parametric influences in torsional systems is presented. The system properties such as polar inertia, torsional stiffness, are represented by a directed graph. The theory of qualitative and quantitative influences is used to develop a technique which predicts the direction of change and accurate estimates of parametric values. Both qualitative and quantitative estimates provide important clues (direction of change and the estimated quantitative change) to vary parametric values. This technique is especially useful for estimating parametric influences on the overall system response and for generating a number of alternate design options. This is complementary to classical methods and conventional finite element method and is validated through examples related to free vibrations of torsional systems. Results presented here show that the estimates obtained using the proposed technique are more accurate compared to those obtained in previous research. Future directions in the context of complex design reasoning systems are also highlighted.
Secondary Structure Prediction Using SVM and Clustering
Authors: Shing H. Doong, Chi Y. Yeh
Venue: Proceedings of the Fourth International Conference on Hybrid Intelligent Systems (2004)

Protein secondary structure can be used to help determine the tertiary structure via the fold recognition method. Predicting the secondary structure from the protein sequence has attracted the attention of many researchers. Support Vector Machine (SVM) is a new learning algorithm that has been successfully applied to many prediction problems. However, the algorithm takes a long time to train the prediction model when a large data set is present. It becomes important to revise the method so that the time performance is improved while the accuracy performance is maintained. In this study, we implement a genetic algorithm to cluster the training set before a prediction model is built. Using position specific scoring matrix (PSSM) as part of the input, the hybrid method achieves good performances on sets of 513 non-redundant protein sequences and 294 partially redundant sequences. The results also show that clustering achieves the goal of data preprocessing differently on redundant and non-redundant sets, and it seems almost preferable to cluster the data before prediction is preformed.
A Semi-Supervised Active Learning Framework for Image Retrieval
Authors: Steven C. H. Hoi, Michael R. Lyu
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 2 - Volume 02 (2005)

Although recent studies have shown that unlabeled data are beneficial to boosting the image retrieval performance, very few approaches for image retrieval can learn with labeled and unlabeled data effectively. This paper proposes a novel semi-supervised active learning framework comprising a fusion of semi-supervised learning and support vector machines. We provide theoretical analysis of the active learning framework and present a simple yet effective active learning algorithm for image retrieval. Experiments are conducted on real-world color images to compare with traditional methods. The promising experimental results show that our proposed scheme significantly outperforms the previous approaches.