ppxscal/embedding_network huggingface dataset:
Theory of finite or infinite trees revisited
Authors: Khalil Djelloul, Thi-bich-hanh Dao, Thom FrÜhwirth
Venue: Theory and Practice of Logic Programming (2008)

We present in this paper a first-order axiomatization of an extended theory T of finite or infinite trees, built on a signature containing an infinite set of function symbols and a relation finite(t), which enables to distinguish between finite and infinite trees. We show that T has at least one model and prove its completeness by giving not only a decision procedure, but a full first-order constraint solver that gives clear and explicit solutions for any first-order constraint satisfaction problem in T. The solver is given in the form of 16 rewriting rules that transform any first-order constraint ϕ into an equivalent disjunction φ of simple formulas such that φ is either the formula true or the formula false or a formula having at least one free variable, being equivalent neither to true nor to false and where the solutions of the free variables are expressed in a clear and explicit way. The correctness of our rules implies the completeness of T. We also describe an implementation of our algorithm in CHR (Constraint Handling Rules) and compare the performance with an implementation in C++ and that of a recent decision procedure for decomposable theories.
Mathematical Logic
Authors: Ian Chiswell, Wilfrid Hodges
Venue: Oxford Texts In Logic (2007)

Assuming no previous study in logic, this informal yet rigorous text covers the material of a standard undergraduate first course in mathematical logic, using natural deduction and leading up to the completeness theorem for first-order logic. At each stage of the text, the reader is given an intuition based on standard mathematical practice, which is subsequently developed with clean formal mathematics. Alongside the practical examples, readers learn what can and can't be calculated; for example the correctness of a derivation proving a given sequent can be tested mechanically, but there is no general mechanical test for the existence of a derivation proving the given sequent. The undecidability results are proved rigorously in an optional final chapter, assuming Matiyasevich's theorem characterising the computably enumerable relations. Rigorous proofs of the adequacy and completeness proofs of the relevant logics are provided, with careful attention to the languages involved. Optional sections discuss the classification of mathematical structures by first-order theories; the required theory of cardinality is developed from scratch. Throughout the book there are notes on historical aspects of the material, and connections with linguistics and computer science, and the discussion of syntax and semantics is influenced by modern linguistic approaches. Two basic themes in recent cognitive science studies of actual human reasoning are also introduced. Including extensive exercises and selected solutions, this text is ideal for students in logic, mathematics, philosophy, and computer science.
Test of independence in a 2 × 2 contingency table with nonignorable nonresponse via constrained EM algorithm
Authors: Keiji Takai, Yutaka Kano
Venue: Computational Statistics Data Analysis (2008)

Test of independence for 2x2 contingency tables with nonignorable nonresponses is discussed. Dependency assumption between two observed outcomes is required to achieve identification in many models with nonignorable nonresponses in the analysis of 2x2 contingency tables (e.g., [Ma, W.-Q., Geng, Z., Li, X.-T., 2003. Identification of nonresponse mechanisms for two-way contingency tables. Behaviormetrika 30, 125-144]). The assumption is, however, violated under the null hypothesis when implementing the test of independence. In this article, we introduce a new simple assumption to achieve identification. The assumption involves pre-specified parameters. EM algorithms for finding the MLE are numerically unstable when there are nonlinear constraints, which are created by models treating nonignorable nonresponses. In the analysis of contingency tables, estimated values often fall outside the admissible region. We propose a new EM type algorithm to stably calculate the constrained MLE, and apply it to make the test of independence for a real data set (crime data). We compare empirical performance among several testing procedures for independence. It turns out that the new EM type algorithm works well to calculate the MLE, and that the nonignorable model with the correctly specified parameters performs best while the conventional chi-square test of independence works fairly well.
Efficient Policy Conflict Analysis for Autonomic Network Management
Authors: Steven Davy, Brendan Jennings, John Strassner
Venue: Proceedings of the Fifth IEEE Workshop on Engineering of Autonomic and Autonomous Systems (2008)

Abstract Autonomic network management strives to reduce the complexity associated to managing large scale communications networks. Policy based management is a critical facilitator for this vision and more importantly policy conflict analysis processes must be efficient and scalable to cope with the dynamicity and size of such communications networks. We present an efficient policy selection process for policy conflict analysis that maintains a history of previous policy comparisons in a tree based data structure to reduce the number comparisons required in subsequent iterations. The ability to incorporate historical information into the selection process stems from the two phase approach we take in our conflict analysis algorithm. The first phase of the algorithm initialises a relationship pattern matrix between a candidate policy and a deployed policy, the second phase matches this pattern against a conflict signature. Previous solutions compare candidate policies against all deployed policies sequentially, however our approach can re-use the patterns already discovered from previous iterations of the algorithm to reduce the number of comparisons. Experimental results presented here show that significant performance improvements can be made using this approach, however the degree of this improvement is dependent on the nature of the relationships between deployed policies.
The parallel three-processor fifth order diagonally implicit Runge-Kutta methods for solving ordinary differential equations
Authors: Ummul Khair Salma Din, Fudziah Ismail, Mohamed Suleiman, Zanariah Abdul Majid, Mohamed Othman
Venue: Proceedings of the 12th WSEAS International Conference on Applied Mathematics (2007)

Fifth order diagonally implicit Runge-Kutta methods with a modified sparsity structure suitable for parallel implementations on three processors are developed. The efficiency of the methods in terms of accuracy to solve a standard set of problems is compared to an established method. From the results we can conclude the new methods are comparable to the existing method.
Detecting Network Anomalies Using Different Wavelet Basis Functions
Authors: Wei Lu, Mahbod Tavallaee, Ali A. Ghorbani
Venue: Proceedings of the Communication Networks and Services Research Conference (2008)

Signal processing techniques have been applied recently for analyzing and detecting network anomalies due to their potential to find novel or unknown intrusions. In this paper, we present a novel network anomaly detection approach based on wavelet analysis, approximate autoregressive and outlier detection techniques. In order to characterize network traffic behaviors, we proposed fifteen features and applied them as the input signals in our wavelet-based approach. We then evaluate our approach with the 1999 DARPA intrusion detection dataset and conduct a comprehensive comparison for four different typical wavelet basis functions on detecting network intrusions. Our work aims to unveil a question when applying wavelet techniques for detecting network attacks, that is "do wavelet basis functions have an important impact on the intrusion detection performance?". Moreover, to the best of our knowledge, the work is the first to analyze the 1999 DARPA's network traffic using flow data instead of its original raw packet data.
Detecting Clusters and Outliers for Multi-dimensional Data
Authors: Yong Shi
Venue: Proceedings of the 2008 International Conference on Multimedia and Ubiquitous Engineering (2008)

Nowadays many data mining algorithms focus on clustering methods. There are also a lot of approaches designed for outlier detection. We observe that, in many situations, clusters and outliers are concepts whose meanings are inseparable to each other, especially for those data sets with noise. Thus, it is necessary to treat clusters and outliers as concepts of the same importance in data analysis. In this paper, we present a cluster-outlieriterative detection algorithm, tending to detect the clusters and outliers in another perspective for noisy data sets. In this algorithm, clusters are detected and adjusted according to the intra-relationship within clusters and the inter-relationship between clusters and outliers, and vice versa. The adjustment and modification of the clusters and outliers are performed iteratively until a certain termination condition is reached. This data processing algorithm can be applied in many fields such as pattern recognition, data clustering and signal processing.
Characterization of Standard Cells for Intra-Cell Mismatch Variations
Authors: Savithri Sundareswaran, Jacob A. Abraham, Alexandre Ardelea, Rajendran Panda
Venue: Proceedings of the 9th international symposium on Quality Electronic Design (2008)

With the adoption of statistical timing across industry, there is a need to characterize all gates/cells in a digital library for delay variations (referred to as, statistical characterization). Statistical characterization need to be performed efficiently with acceptable accuracy as a function of several process and environment parameter variations. In this paper, we propose an approach to consider intra-cell process mismatch variations to characterize a cell's delay and output transition time (output slew) variations. A straightforward approach to address this problem is to model these mismatch variations by characterizing for each device fluctuation separately. However, the runtime complexity for such characterization becomes of the order of number of devices in the cell and the number of simulations required can easily become infeasible. We analyze the fluctuations in switching and non-switching devices and their impact on delay variations. Using these properties of the devices, we propose a clustering approach to characterize for cell's delay variations due to intra-cell mismatch variations. The proposed approach results in as much as 12X runtime improvements with acceptable accuracy, compared with Monte Carlo simulations. We show that this approach ensures an upper-bound on the results while keeping the number of simulations for each cell independent of the number of devices.
RDF-Based Approach to Data Transform Composition
Authors: Jungmin Shin, Joachim Hammer, Herman Lam
Venue: Proceedings of the Seventh IEEE/ACIS International Conference on Computer and Information Science (icis 2008) (2008)

In order to share data, creating a data transform is a mandatory step since disparate data sources have heterogeneities in data representation. Manual transform creation is extremely tedious and error-prone even though we have a repository of usable transforms. Recent work has focused on finding a data transform as part of data mapping or schema matching. However, the work is mostly about a structural data mapping or applying a single data transform between schemas. We consider a \textit{transform composition} which reuses existing transforms for constructing users' desired transforms. Users' desired transforms and existing transforms are described in our transform model represented in RDF triples. Our transform model includes not only semantics of input/output fields but also behavior of a transform. We model a transform composition problem as a graph search problem. Also, we describe overall architecture of our system which automatically discovers users' desired transforms.
An Efficient Piecewise Hashing Method for Computer Forensics
Authors: Long Chen, Guoyin Wang
Venue: Proceedings of the First International Workshop on Knowledge Discovery and Data Mining (2008)

Hashing, a basic tool in computer forensics, is used to ensure data integrity and to identify known data objects efficiently. Unfortunately, intentional tiny modified file can not be identified using this traditional technique. Context triggered piecewise hashing separates a file into pieces using local context characteristic, and produces a hash sequence as a hash signature. The hash signature can be used to identify similar files with tiny modifications such as insertion, replacement and deletion. The algorithm of currently available scheme is designed for junk mail detection, which is low efficient and not suitable for file system investigation. In this paper, an improved algorithm based on the Store-Hash and Rehash idea is developed for context triggered piecewise hashing technique. Experiment results show that the performance of speed and the ability of similarity detection of the new scheme are better than that of spamsum. It is valuable for forensics practice. Keywords: Computer forensics, Hash, File system investigation, Digital forensics
Computational Geometry: Algorithms and Applications, 3rd ed. edition
Authors: Mark de Berg, Otfried Cheong, Marc van Kreveld, Mark Overmars
Venue:  (2008)

This well-accepted introduction to computational geometry is a textbook for high-level undergraduate and low-level graduate courses. The focus is on algorithms and hence the book is well suited for students in computer science and engineering. Motivation is provided from the application areas: all solutions and techniques from computational geometry are related to particular applications in robotics, graphics, CAD/CAM, and geographic information systems. For students this motivation will be especially welcome. Modern insights in computational geometry are used to provide solutions that are both efficient and easy to understand and implement. All the basic techniques and topics from computational geometry, as well as several more advanced topics, are covered. The book is largely self-contained and can be used for self-study by anyone with a basic background in algorithms. In this third edition, besides revisions to the second edition, new sections discussing Voronoi diagrams of line segments, farthest-point Voronoi diagrams, and realistic input models have been added.
Detection of anatomical point landmarks in medical images using fuzzy logic
Authors: S. Alayón, C. S. González, L. Moreno, R. Cárdenes, E. Suárez, J. Ruiz-Alzola
Venue: Proceedings of the 4th WSEAS International Conference on Applied Informatics and Communications (2004)

In this paper we present an automatic and fast method for the detection of anatomical point landmarks. The method is based on fuzzy systems. Different techniques are used to extract information about the problem: tensor analysis of the image, multiscale analysis and distance measurements. Fuzzy logic is introduced to combine the information extracted with these techniques and discriminate between real anatomical point landmarks and false detections. The proposed method has been successfully applied to accurately detect the typical anatomical point landmarks in midsagittal Magnetic Resonance Imaging (MRI) of the brain.
Random walks and the regeneration time
Authors: Andrew Beveridge, László Lovász
Venue: Journal of Graph Theory (1998)

Consider a graph G and a random walk on it. We want to stop the random walk at certain times (using an optimal stopping rule) to obtain independent samples from a given distribution &rho; on the nodes. For an undirected graph, the expected time between consecutive samples is maximized by a distribution equally divided between two nodes, and so the worst expected time is 1-4 of the maximum commute time between two nodes. In the directed case, the expected time for this distribution is within a factor of 2 of the maximum. &copy; 1998 John Wiley Sons, Inc. J. Graph Theory 29: 5762, 1998
RealNet: A Topology Generator Based on Real Internet Topology
Authors: Lechang Cheng, Norm C. Hutchinson, Mabo R. Ito
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

One of the challenges of large-scale network simulations is the lack of scalable and realistic Internet topology generators. Previous topology generators are either not scalable to millions of nodes, or not able to capture characteristics of the Internet topology. In this work, we propose a topology generator which can generate accurate large-scale models of the Internet. We extract the AS (autonomous system) level and router level topology of the Internet with various data sources such as BGP routing tables and traceroute records. With the real Internet topology, we infer the AS topology and the commercial relationship among ASes. We also group the routers into clusters according to their positions in the Internet. A compact routing core is built with the AS topology and router cluster topology. Each generated topology consists of the routing core and a set of end-hosts connected to router clusters. The generated topology is realistic since its routing core is extracted from Internet. We make the assumption of uniform routing policy within an AS. Therefore, the routing path calculation of any source/destination pair consists of finding the AS path for the source/destination ASes and finding the router level path within each AS in the AS path. Since the routing pate depends only on the routing core, its size is independent of the number of end-hosts in the generated topology.
Research on Vendor Selection under Fuzzy Situation
Authors: Yu Ying
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

A multi-product, multi-objective vendor selection model which incorporate fuzzy demand, shortage cost and fuzzy chance constraints, is proposed in this paper. Different weight is assigned to each objective according to the decision-maker’s preference, and the model is converted into a single-objective hybrid integer programming. A genetic algorithm combined with fuzzy simulation technology is provided to find the optimal solutions. Lastly numerical examples are given to demonstrate the validity of the proposed algorithm.
On the accuracy of operator splitting for the monodomain model of electrophysiology
Authors: H. J. Schroll, G. T. Lines, A. Tveito
Venue: International Journal of Computer Mathematics (2007)

Nonlinear systems of time dependent partial differential equations of real life phenomena tend to be very complicated to solve numerically. One common approach to solve such problems is by applying operator splitting which introduces subproblems that are easier to handle. The solutions of the subsystems are usually glued together by either the Godunov method (first-order) or the Strang method (second-order). However, the accuracy of such an approach may be very hard to analyse because of the complexity of the equations involved. The purpose of the present paper is to introduce another line of reasoning concerning the accuracy of operator splitting. Let us assume that a fully coupled and implicit discretization of the complete system has been developed. Under appropriate conditions on the continuous problem, such discretizations provide reasonable and convergent approximations. As in the continuous case, operator splitting can be utilized to obtain tractable algebraic subsystems. The problem we address in the present paper is to obtain a bound on the difference between the fully coupled implicit discrete solutions, uh, and the solutions, uh, s, obtained by applying operator splitting to these discrete equations. Suppose we know that uh converges to the analytical solution u as the grid is properly refined and, applying the results from this paper, that uh, s converges toward uh under grid refinement. Then, by the triangle inequality, also the splitting approximation uh, s converges toward the analytical solution u and convergence is thus obtained for an approximation that, from a practical point of view, is easier to compute.
Targeted Change. Are You Aready Irrelevant?
Authors: Max Noble
Venue: Proceedings of the 19th Australian Conference on Software Engineering (2008)

No change happens in isolation, and the rate of change can have a significant impact on the acceptance level of a change. This paper reviews the interrelationships between technology, people at the micro, and macro level of organisational structure, business goals, and the external business environment as they interact within an IT change cycle. Mixing personal experience with industry case studies this paper examines how the implementation of a change cycle has an immediate feedback into the continued development of the change cycle; it demonstrates that human factors and communication mechanisms have more of an impact on the success level of a change programme than the selection of the 'right' technology or being an early adopter of new development techniques. Focusing on change within the software and IT domain examples are reviewed from the arenas of IT gaming, air traffic control, and general large-scale complex system integration change cycles. Using the Change Cycle definition developed by Brock and Salerno as a reference structure this paper examines each of the six key phases of the change cycle as they relate to staff and adoption of technical evolutions.
Interference power statistics in ad-hoc and sensor networks
Authors: R. Hekmat, P. Van Mieghem
Venue: Wireless Networks (2008)

There exist accurate calculation methods for estimation of interference power sum statistics in fixed-topology wireless networks based on the log-normal shadowing radio model. Here we publish essential additions to these estimation methods to expand their use to sensor networks and ad-hoc networks with changing topology. In our calculations we take into account radio propagation conditions, density of nodes, size of the network, traffic load per node and MAC protocol characteristics. The accuracy of our calculation method is verified by simulations. We highlight the influence of MAC protocols on interference and show that an increase in network size or in node density does not necessarily lead into higher interference values. Our results can be deployed to estimate the network capacity.
Impulse noise models for images
Authors: Kh. Manglem Singh, Prabin K. Bora
Venue: Proceedings of the 4th WSEAS International Conference on Telecommunications and Informatics (2005)

We propose two impulse noise models in this paper. The first model is Bernoulli-state impulse noise mode for gray-scale images. The state representing occurrence of the impulse noise at any location is modelled by a binary Bernoulli process and impulse noise can take values in the dynamical range of the image according to some underlying distribution in this model. The second impulse noise model is for a generalized three channel multivariate images.