ppxscal/embedding_network huggingface dataset:
A new variant of the Pathfinder algorithm to generate large visual science maps in cubic time
Authors: A. Quirin, O. Cordón, J. Santamaría, B. Vargas-Quesada, F. Moya-Anegón
Venue: Information Processing and Management: an International Journal (2008)

In the last few years, there is an increasing interest to generate visual representations of very large scientific domains. A methodology based on the combined use of ISI-JCR category cocitation and social networks analysis through the use of the Pathfinder algorithm has demonstrated its ability to achieve high quality, schematic visualizations for these kinds of domains. Now, the next step would be to generate these scientograms in an on-line fashion. To do so, there is a need to significantly decrease the run time of the latter pruning technique when working with category cocitation matrices of a large dimension like the ones handled in these large domains (Pathfinder has a time complexity order of O(n^4), with n being the number of categories in the cocitation matrix, i.e., the number of nodes in the network). Although a previous improvement called Binary Pathfinder has already been proposed to speed up the original algorithm, its significant time complexity reduction is not enough for that aim. In this paper, we make use of a different shortest path computation from classical approaches in computer science graph theory to propose a new variant of the Pathfinder algorithm which allows us to reduce its time complexity in one order of magnitude, O(n^3), and thus to significantly decrease the run time of the implementation when applied to large scientific domains considering the parameter q=n-1. Besides, the new algorithm has a much simpler structure than the Binary Pathfinder as well as it saves a significant amount of memory with respect to the original Pathfinder by reducing the space complexity to the need of just storing two matrices. An experimental comparison will be developed using large networks from real-world domains to show the good performance of the new proposal.
A correlative criterion for the stability of sigma-delta based IIR filter: application to an FIR-like bit-stream filter
Authors: Adam Charles Thompson, Zahir M. Hussain, Peter O'Shea
Venue: Proceedings of the 2nd WSEAS International Conference on Electronics, Control and Signal Processing (2003)

Recently we have proposed a structure for single-bit filtering. This structure contains a ternary finite-impulse-response filter cascaded with a first-order infinite-impulse-response (IIR) filter. The recursive IIR filter contains a sigma-delta modulator embedded within the loop. This structure filters input signals and produces a single-bit output signal. The stability of such a system has yet to be analyzed. In this paper we use a new mean-square-error correlation-based method to determine the stability of sigma-delta based IIR filters. The approach is applied to test the stability of the above single-bit filtering system.
The gradient and heavy ball with friction dynamical systems: the quasiconvex case
Authors: X. Goudou, J. Munier
Venue: Mathematical Programming: Series A and B (2008)

We consider the gradient system $$\dot x(t)+\nabla\phi(x(t))=0$$ and the so-called heavy ball with friction dynamical system $$\ddot x(t) +\lambda\dot x(t)+\nabla\phi(x(t))=0$$, as well as an implicit discrete (proximal) version of it, and study the asymptotic behavior of their solutions in the case of a smooth and quasiconvex objective function &#x03a6;. Minimization properties of trajectories are obtained under various additional assumptions. We finally show a minimizing property of the heavy ball method which is not shared by the gradient method: the genericity of the convergence of each trajectory, at least when &#x03a6; is a Morse function, towards local minimum of &#x03a6;.
Discrete fractional Fourier transform based on the eigenvectors of tridiagonal and nearly tridiagonal matrices
Authors: Magdy Tawfik Hanna, Nabila Philip Attalla Seif, Waleed Abd El Maguid Ahmed
Venue: Digital Signal Processing (2008)

The recent emergence of the discrete fractional Fourier transform (DFRFT) has caused a revived interest in the eigenanalysis of the discrete Fourier transform (DFT) matrix F with the objective of generating orthonormal Hermite-Gaussian-like eigenvectors. The Grunbaum tridiagonal matrix T-which commutes with matrix F-has only one repeated eigenvalue with multiplicity two and simple remaining eigenvalues. A detailed eigendecomposition of matrix T is performed with the objective of deriving two orthonormal eigenvectors-common to both the F and T matrices-pertaining to the repeated eigenvalue of T. The nearly tridiagonal matrix S first introduced by Dickinson and Steiglitz and later studied by Candan et al.-which commutes with matrix F-is rigorously proved to reduce to a 2x2 block diagonal form by means of a similarity transformation defined in terms of an involutary matrix P. Moreover explicit expressions are derived for the elements of the two tridiagonal submatrices forming the two diagonal blocks in order to circumvent the need for performing two matrix multiplications. Although matrix T has the merit of being tridiagonal and does not need the tridiagonalization step as matrix S, the simulation results show that the eigenvectors of matrix S better approximate samples of the Hermite-Gaussian functions than those of matrix T and moreover they have a shorter computation time due to the block diagonalization result. Consequently they can serve as a better basis for developing the DFRFT.
Crystal Structures and Computer Screened Inhibitors of Helicobacter pylori Undecaprenyl Pyrophosphate Synthase
Authors: Chih-Jung Kuo, Rey-Ting Guo, I-Lin Lu, Hong-Gi Liu, Su-Ying Wu, Tzu-Ping Ko, Andrew H. -J. Wang, Po-Huang Liang
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

Helicobacter Pylori colonizes the human gastric epithelium and causes diseases such as gastritis, peptic ulcers, and stomach cancer. Undecaprenyl pyrophosphate synthase (UPPs), which catalyzes consecutive condensation reactions of farnesyl pyrophosphate with eight isopentenyl pyrophosphate to form lipid carrier for bacterial peptidoglycan biosynthesis, represents a potential target for developing new antibiotics. In the present study, X-ray structural analysis and computer virtual screening of inhibitors were performed for H. pylori UPPs. The 3-D structure of H. pylori UPPs was solved, with subtle variations from that of E. coli UPPs. Using the structures, two hits identified from 58,635 compounds through computer virtual screening displayed differential activities against H. pylori and E. coli UPPs.
Kleio: a knowledge-enriched information retrieval system for biology
Authors: Chikashi Nobata, Philip Cotter, Naoaki Okazaki, Brian Rea, Yutaka Sasaki, Yoshimasa Tsuruoka, Jun'ichi Tsujii, Sophia Ananiadou
Venue: Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval (2008)

Kleio is an advanced information retrieval (IR) system developed at the UK National Centre for Text Mining (NaCTeM)1. The system offers textual and metadata searches across MEDLINE and provides enhanced searching functionality by leveraging terminology management technologies.
A Harnack inequality for Dirichlet eigenvalues
Authors: Fan Chung, S.-T. Yau
Venue: Journal of Graph Theory (2000)

We prove a Harnack inequality for Dirichlet eigenfunctions of abelian homogeneous graphs and their convex subgraphs. We derive lower bounds for Dirichlet eigenvalues using the Harnack inequality. We also consider a randomization problem in connection with combinatorial games using Dirichlet eigenvalues. &copy; 2000 John Wiley & Sons, Inc. J Graph Theory 34: 247&ndash;257, 2000
Risk of using pirated software and its impact on software protection strategies
Authors: Samuel Shu Kin Kwan, Jeevan Jaisingh, Kar Yan Tam
Venue: Decision Support Systems (2008)

The software protection strategy of software developer and the inherent risk to end user in using pirated software are two major factors that affect a user's decision on whether to purchase or pirate a software product. This paper analyzes the optimal protection strategy for software developer in horizontally and vertically differentiated markets. We find that the implementation cost of software protection constitutes the primary factor for software developers to determine their software protection strategies. However, in a vertically differentiated market, the lower quality product should always adopt a non-protection strategy, regardless of the protection implementation cost. In other cases, protection would only be optimal if the protection implementation cost to the software developer is relatively small. These findings are consistent with anecdotal evidence.
Compressing Moving Object Trajectory in Wireless Sensor Networks
Authors: Yingqi Xu, Wang-Chien Lee
Venue: International Journal of Distributed Sensor Networks (2007)

Some object tracking applications can tolerate delays in data collection and processing. Taking advantage of the delay tolerance, we propose an efficient and accurate algorithm for in-network data compression, called delay-tolerant trajectory compression (DTTC). In DTTC, a cluster-based infrastructure is built within the network. Each cluster head compresses an object's movement trajectory detected within its cluster by a compression function. Rather than transmitting all sensor readings to the sink node, the cluster head communicates only the compression parameters, which not only provide the sink node expressive yet traceable models about the object movements, but also significantly reduce the total amount of data communication required for tracking operations. DTTC supports a broad class of movement trajectories using two proposed techniques, DC-compression and SW-compression, and an efficient trajectory segmentation scheme, which are designed for improving the trajectory compression accuracy at less computation cost. Moreover, we analyze the underlying cluster-based infrastructure and mathematically derive the optimum cluster size, aiming at minimizing the total communication cost of the DTTC algorithm. An extensive simulation has been conducted to compare DTTC with competing prediction-based tracking technique, DPR [28]. Simulation results show that DTTC exhibits superior performance in terms of accuracy, communication cost and computation cost and soundly outperforms DPR with all types of movement trajectories.
Hybrid wavelet and chaos theory for runoff forecasting
Authors: Chen Xi, Jiang Chuanwen, Wang Yu, Zhou Jian
Venue: Proceedings of the 5th WSEAS/IASME International Conference on Systems Theory and Scientific Computation (2005)

This paper introduced a method of decomposing non-stationary runoff time series. By wavelet decomposing, the runoff time series is decomposed into stationary time series and stochastic time series, and AR(n) model be imposed for forecasting stationary time series. By studying chaos characteristic of stochastic time series, this paper put forward a nonlinear chaos dynamics-forecasting model to dispose runoff time series with high-embedded dimension. It can effectively decrease the Lyapunov exponential sum in added dimensions of reconstruction set when the dimensions of reconstructed space are increased. Finally, the forecasting result is reconstructed based on wavelet theory. The forecasting result of original runoff time series is achieved. The method is high precision and feasible through example test.
An on-chip multichannel waveform monitor for diagnosis of systems-on-chip integration
Authors: Koichiro Noguchi, Makoto Nagata
Venue: IEEE Transactions on Very Large Scale Integration (VLSI) Systems (2007)

An on-chip multichannel waveform monitoring technique enhances built-in test and diagnostic capabilities of systems-on-a-chip (SoC) integration. The proposed multichannel monitor includes multiple probing front-end modules and a single shared waveform acquisition kernel that consists of an incremental variable step delay generator and an incremental reference voltage generator, featuring adaptive sample time generation for the operation of a target circuit and unidirectional waveform acquisition flow for area-efficient control. A 16-channel prototype in 0.18-µm CMOS technology demonstrated on-chip waveform acquisition at 40-ps and 200-µV resolutions. Combined on- and off-chip streamed-bit processing achieves background continuous wave-form acquisition at 260 ms per single timing point for repetitive signals, while eliminating the integration of on-die high-capacity memory. A 700 µm × 600 µm area was occupied by a waveform acquisition kernel and an additional 60 µm × 100 µm area for each front-end module. The developed on-chip multichannel waveform monitoring technique is waveform accurate, area efficient, and suitable for diagnosis toward power supply and signal integrity in analog and digital circuits in mixed-signal SoC integration.
Enhanced hot spot detection heuristics for embedded java just-in-time compilers
Authors: Seong-Won Lee, Soo-Mook Moon, Seong-Moo Kim
Venue: Proceedings of the 2008 ACM SIGPLAN-SIGBED conference on Languages, compilers, and tools for embedded systems (2008)

Most Java just-in-time compilers (JITC) try to compile only hot methods since the compilation overhead is part of the running time. This requires precise and efficient hot spot detection, which includes distinguishing hot methods from cold methods, detecting them as early as possible, and paying a small runtime overhead for detection. A hot method could be identified by measuring its running time during interpretation since a long-running method is likely to be a hot method. However, precise measurement of the running time during execution is too expensive, especially in embedded systems, so many counter-based heuristics have been proposed to estimate it. The Simple heuristic counts only method invocations without any consideration of loops [1], while Sun's HotSpot heuristic counts loop iterations as well, but does not consider loop sizes or method sizes [2,14]. The static analysis heuristic estimates the running time of a method by statically analyzing loops or heavy-cost bytecodes but does not measure their dynamic counts [3]. Although the overhead of these heuristics is low, they do not estimate the running time precisely, which may lead to imprecise hot spot detection. This paper proposes a new hot spot detection heuristic which can estimate the running time more precisely than others with a relatively low overhead. It dynamically counts only important bytecodes interpreted, but with a simple arithmetic calculation it can obtain the precise count of all interpreted bytecodes. We also propose employing a static analysis technique to predict those hot methods which spend a huge execution time once invoked. This static prediction can allow compiling these methods at their first-invocation, complementing the proposed dynamic estimation technique. We implemented both, which led to a performance benefit of 10% compared to the HotSpot heuristic.
Exploring educational standard alignment: in search of 'relevance'
Authors: René Reitsma, Byron Marshall, Michael Dalton, Martha Cyr
Venue: Proceedings of the 8th ACM/IEEE-CS joint conference on Digital libraries (2008)

The growing availability of online K-12 curriculum is increasing the need for meaningful alignment of this curriculum with state-specific standards. Promising automated and semi-automated alignment tools have recently become available. Unfortunately, recent alignment evaluation studies report low inter-rater reliability, e.g., 32% with two raters and 35 documents. While these results are in line with studies in other domains, low reliability makes it difficult to accurately train automatic systems and complicates comparison of different services. We propose that inter-rater reliability of broadly defined, abstract concepts such as 'alignment' or 'relevance' must be expected to be low due to the real-world complexity of teaching and the multidimensional nature of the curricular documents. Hence, we suggest decomposing these concepts into less abstract, more precise measures anchored in the daily practice of teaching. This article reports on the integration of automatic alignment results into the interface of the Teach Engineering collection and on an evaluation methodology intended to produce more consistent document relevance ratings. Our results (based on 14 raters x 6 documents) show high inter-rater reliability (61 - 95%) on less abstract relevance dimensions while scores on the overall 'relevance' concept are (as expected) lower (64%). Despite a relatively small sample size, regression analysis of our data resulted in an explanatory (R2 = .75) and statistically stable (p-values
Asymptotic critical total power for k-connectivity of wireless networks
Authors: Honghai Zhang, Jennifer C. Hou
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

An important issue in wireless ad hoc networks is to reduce the transmission power subject to certain connectivity requirement. In this paper, we study the fundamental scaling law of the minimum total power (termed as critical total power) required to ensure k-connectivity in wireless networks. Contrary to several previous results that assume all nodes use a (minimum) common power, we allow nodes to choose different levels of transmission power. We show that under the assumption that wireless nodes form a homogeneous Poisson point process with density λ in a unit square region [0, 1]2, the critical total power required to maintain k-connectivity is Θ ((Γ(c/2+k)/(k-1)!)λ1-c/2) with probability approaching one as λ goes to infinity, where c is the path loss exponent. If k also goes to infinity, the expected critical total power is of the order of kc/2λ1-c/2. Compared with the results that all nodes use a common critical transmission power for maintaining k-connectivity, we show that the critical total power can be reduced by an order of (log λ)c/2 by allowing nodes to optimally choose different levels of transmission power. This result is not subject to any specific power/topology control algorithm, but rather a fundamental property of wireless networks.
Design of AI neural network based controller for controlling dissolved oxygen concentration in a sequencing batch reactor
Authors: Azwar, M. M. Rashid, M. A. Hussain
Venue: International Journal of Knowledge-based and Intelligent Engineering Systems (2008)

The design and development of the neural network based controller performance for the activated sludge process in sequencing batch reactor (SBR) is presented. In this paper, here we give a comparative study of various neural network based controllers such as the direct inverse control, internal model control and hybrid neural network control strategies to maintain the dissolved oxygen level of an activated sludge system by manipulating the air flow rate. The neural network inverse model based controller with the model-based scheme represents the controller, which relies solely upon the simple neural network inverse model. In the internal model control, both the forward and inverse model is used directly as elements within the feedback loop. The hybrid neural network control consists of a basic neural network (NN) controller in parallel with a proportional integral (PI) controller. Various simulation test involving multiple set point changes, disturbances rejection and noise effects were performed to review the performances of these various controllers. From the results it can be seen that hybrid controller gives best results in tracking set point changes value the disturbances and noise effects.
Augmenting graphs to meet edge-connectivity requirements
Authors: A. Frank
Venue: Proceedings of the 31st Annual Symposium on Foundations of Computer Science (1990)

The problem of determining the minimum number gamma of edges to be added to a graph G so that in the resulting graph the edge-connectivity between every pair (u,v) of nodes is at least a prescribed value r(u,v) is treated. A min-max formula for gamma is derived, and a polynomial-time algorithm for computing gamma is described. The directed counterpart of the problem is also solved for the case in which r(u,v)=k>or=1. The approach used makes it possible to solve a degree-constrained version of the problem. The minimum-cost augmentation problem can also be solved in polynomial time provided that the edge costs arise from node costs.
Dminating sets for outerplanar graphs
Authors: Val Pinciu
Venue: Proceedings of the 5th WSEAS International Conference on Applied Mathematics (2004)

We provide lower and upper bounds for the domination numbers and the connected domination numbers for outerplanar graphs. We also provide a recursive algorithm that finds a connected domination set for an outerplanar graph. Finally, we show that for outerplanar graphs where all bounded faces are 3-cycles, the problem of determining the connected domination number is equivalent to an art gallery problem, which is known to be NP-hard.
Multi-path routing protocol using cross-layer congestion-awareness in wireless mesh network
Authors: Hung Quoc Vo, Young Yig Yoon, Choong Seon Hong
Venue: Proceedings of the 2nd international conference on Ubiquitous information management and communication (2008)

Recently, the WMNs (Wireless Mesh Network) have increased their popularity and kept the interest of the most important research groups all over the world due to their self-configuring, self-healing capabilities, as well as their low equipment and deployment cost. Most of research work carried out in WMN is prone to be simple, practical to build up confidence in commercial implementation of these networks. In this paper, we present a multi-path routing protocol using Hop-Count metric that can be aware of congestion by collecting information from MAC layer. The primary advantage of our paper is to provide a simple and stable multi-path routing algorithm that can provide better than best-effort to real-time applications in wireless environment but need much less overhead compared to QoS-aware routing with two kinds of metrics: bandwidth and WCETT (Weighted Cumulative Expected Transmission Time).
Robust stabilization of uncertain impulsive switched systems with delayed control
Authors: Honglei Xu, Kok Lay Teo
Venue: Computers Mathematics with Applications (2008)

In this paper, stability criteria and switching controllers' design problems for uncertain impulsive switched systems with input delay are investigated by using the receding horizon method. Some LMI conditions are derived to guarantee asymptotical stability of an impulsive switched system under a certain designed delayed controller. Finally, a numerical example is presented to illustrate the effectiveness of the results obtained.
Parallel Computation of Similarity Measures Using an FPGA-Based Processor Array
Authors: Darshika G. Perera, Kin Fun Li
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications (2008)

An enormous amount of data needs to be processed in many data mining applications. In addition to algorithmic development, hardware support is imperative to improve the effectiveness and efficiency of these applications. We are investigating various hardware architectural design techniques and methodologies to support data mining at the chip level. In this work, we focus on the design of an FPGA-based processor array for the computation of similarity matrix, a commonly used data structure to represent the similarity among a set of feature vectors, with each matrix element representing the computed similarity measure between two vectors. An algorithm is developed to assign computation efficiently to the array of processing elements. Theoretical performance metrics are derived and compared to the experimental results. Performance gains using the processor array over software implementations are also presented and discussed.