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Given a variety X over a perfect field, we study the partition defined on X by the multiplicity (into equimultiple points), and the effect of blowing up at smooth equimultiple centers. Over fields of characteristic zero we prove resolution of singularities by using the multiplicity as an invariant, instead of the Hilbert Samuel function. [ABSTRACT FROM AUTHOR]

Abstract: Firing tests of a small caliber experimental gun barrel made of a cobalt-base alloy have been conducted with the purpose of determining the degree of wear and erosion due to excessive firing durations. The small amount of barrel material loss makes the cobalt-base alloy an excellent candidate for use as a gun liner. An unusual wear pattern resulting from this loss was observed near the muzzle. Elimination of chemical and thermal effects made a plausible explanation of the wear pattern possible. [Copyright &y& Elsevier]

Abstract: Perfect vertex elimination schemes are part of the characterizations for several classes of graphs, including chordal and cop-win. Partial elimination schemes reduce a graph to an important subgraph, for example, -cores and robber-win graphs. We are interested in those partial elimination schemes, in which once a vertex is ready to be eliminated, it stays in that state regardless of which other vertices are eliminated. We show that in such a scheme, the sets of subsets of eliminated vertices, when ordered by inclusion, form an upper locally distributed lattice. We also show that (a) unless they contain a specific induced subgraph, the cop-win orderings have this property, and that (b) the process of cleaning graphs also leads to upper locally distributed lattices. Finally, we ask for an elimination scheme, which graphs are associated with distributive lattices? [Copyright &y& Elsevier]

Abstract: Video surveillance on highway is a hot topic and a great challenge in Intelligent Transportation Systems. In such applications requiring objects extraction, cast shadows induce shape distortions and object fusions interfering performance of high level algorithms. Shadow elimination allows to improve the performances of video object extraction, classification and tracking. In other hand, it is very important to recognize the type of a detected object in order to track reliably and estimate traffic parameters correctly. This paper presents two approaches to enhance automatic traffic surveillance systems. The first deals with the elimination of shadows and the second concerns the classification of vehicles, based on robust vision and image processing. For moving shadow elimination, a contrast model is proposed to describe and remove dynamic shadows based on the idea that a shadow transformation is a change in contrast. For vehicles classification, Hu moments are calculated in a manner to reduce the perspective effects and used to describe vehicles in knowledge base. Experimental results on the various challenging video sequences show that the proposed approach outperforms classification methods of related works (with a classification accuracy of 96.96%), and that the shadow elimination approach performs better than compared works (with detection rate of 95–99% and discrimination rate of 85.7–89%). [Copyright &y& Elsevier]

Lifted inference has been proposed for various probabilistic logical frameworks in order to compute the probability of queries in a time that depends on the size of the domains of the random variables rather than the number of instances. Even if various authors have underlined its importance for probabilistic logic programming (PLP), lifted inference has been applied up to now only to relational languages outside of logic programming. In this paper we adapt Generalized Counting First Order Variable Elimination (GC-FOVE) to the problem of computing the probability of queries to probabilistic logic programs under the distribution semantics. In particular, we extend the Prolog Factor Language (PFL) to include two new types of factors that are needed for representing ProbLog programs. These factors take into account the existing causal independence relationships among random variables and are managed by the extension to variable elimination proposed by Zhang and Poole for dealing with convergent variables and heterogeneous factors. Two new operators are added to GC-FOVE for treating heterogeneous factors. The resulting algorithm, called LP2 for Lifted Probabilistic Logic Programming, has been implemented by modifying the PFL implementation of GC-FOVE and tested on three benchmarks for lifted inference. A comparison with PITA and ProbLog2 shows the potential of the approach. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we have used a complete pivoting strategy to compute the left-looking version of preconditioner. This pivoting is based on the complete pivoting strategy of the version of Gaussian Elimination process. There is a parameter to control the pivoting process. To study the effect of on the quality of the left-looking version of preconditioner with complete pivoting strategy, we have used ten different values of this parameter. In the numerical experiments section, the quality of the left-looking version of preconditioner with complete pivoting strategy has been compared to the quality of the right-looking version of this preconditioner. [Copyright &y& Elsevier]

We prove that in an arbitrary o-minimal structure, every interpretable group is definably isomorphic to a definable one. We also prove that every definable group lives in a cartesian product of one-dimensional definable group-intervals (or one-dimensional definable groups). We discuss the general open question of elimination of imaginaries in an o-minimal structure. [ABSTRACT FROM AUTHOR]

Tamura proved that for any semigroup word U( x, y), if every group satisfying an identity of the form yx ~ xU( x, y) y is abelian, then so is every semigroup that satisfies that identity. Because a group has an identity element and the cancellation property, it is easier to show that a group is abelian than that a semigroup is. If we know that it is, then there must be a sequence of substitutions using xU( x, y) y ~ yx that transforms xy to yx. We examine such sequences and propose finding them as a challenge to proof by computer. Also, every model of y ~ xU( x, y) x is a group. This raises a similar challenge, which we explore in the special case y ~ x y x. In addition, we determine the free model with two generators of some of these identities. In particular, we find that the free model for y ~ x yx has order 32 and is the product of D (the symmetries of a square), C, and C, and point out relations between such identities and Burnside's Problem concerning models of x ~ y. We also examine several identities not related to groups. [ABSTRACT FROM AUTHOR]

Redundant constraints in MBS models severely deteriorate the computational performance and accuracy of any numerical MBS dynamics simulation method. Classically this problem has been addressed by means of numerical decompositions of the constraint Jacobian within numerical integration steps. Such decompositions are computationally expensive. In this paper an elimination method is discussed that only requires a single numerical decomposition within the model preprocessing step rather than during the time integration. It is based on the determination of motion spaces making use of Lie group concepts. The method is able to reduce the set of loop constraints for a large class of technical systems. In any case it always retains a sufficient number of constraints. It is derived for single kinematic loops. [ABSTRACT FROM AUTHOR]

An improved circulating current control method by applying a digital plug-in repetitive controller is discussed for harmonic elimination of a carrier-phase-shift pulse-width-modulation (CPS-PWM)-based modular multilevel converter (MMC) in this paper. The performance of the controller is analyzed in detail based on an improved circulating current control model with the consideration of the submodule voltage disturbance. It is shown that the proposed control method has the merits of simplicity, versatility, and better performance of circulating harmonic current elimination than the traditional proportional integral controller. The stability analysis of the proposed method are also discussed in the paper as well as the design principles. Finally, the experimental results including the steady-state performance and the transient response are given, which validates the feasibility and excellent performance of the proposed control scheme. [ABSTRACT FROM AUTHOR]

The extensive use of pulse width modulation control technology in smart grid will lead to prominent enlargement of high-frequency harmonics. The effects of the distributed capacitances of transmission line and transformer that are neglected previously will be very obvious. The performance of the traditional harmonic eliminating method for wideband harmonic is limited, which will lead to huge challenge to the analysis, evaluation, and elimination of harmonics as well as series and parallel resonance problem. In this paper, to accurately describe the influence of wideband harmonic on smart grid, the multiterminal analysis model of harmonic degradation in smart grid is established, especially the distributed capacitances of the transmission line and the transformer are considered. Then, a novel topology of hybrid active power filter (HAPF) for resonance damping and multitype harmonic eliminating is proposed. The resonance damping model of the new topology is established; analysis results indicate that the proposed HAPF has a good harmonic resonance damping characteristic. Both simulation and experimental results have validated the validity of the theoretical analysis in this paper. [ABSTRACT FROM AUTHOR]

It needs much computation to develop a contact state graph and find an assembly sequence because polyhedral objects consist of a lot of vertices, edges, and faces. In this paper, we propose a new method to eliminate unnecessary contact states in the contact state graph corresponding to a robotic assembly task. In our method, the faces of polyhedral objects are triangulated, and the adjacency of each vertex, edge, and triangle between an initial contact state and a target contact state is defined. Then, this adjacency is used to create contact state graphs at different priorities. When a contact state graph is finished at a higher priority, a lot of unnecessary contact states can be eliminated because the contact state graph already includes at least one realizable assembly sequence. Our priority-based method is compared with a face-based method through statistically analyzing the contact state graphs obtained from different assembly tasks. Finally, our method results in a significant improvement in the final performance. [ABSTRACT FROM AUTHOR]

A new type of partially global consistency derived from (2, k)-consistency called bounded (2, k)- consistency (B2C-consistency) is presented in this paper. It is designed for application in propositional satisfiability (SAT) as a building block for a preprocessing tool. Together with the new B2C-consistency a special mechanism for selecting regions of the input SAT instance with difficult constraint setup was also proposed. This mechanism is used to select suitable difficult sub-problems whose simplification through consistency can lead to a significant reduction in the effort needed to solve the instance. A new prototype preprocessing tool preprocessSIGMA which is based on the proposed techniques was implemented. As a proof of new concepts a competitive experimental evaluation on a set of relatively difficult SAT instances was conducted. It showed that our prototype preprocessor is competitive with respect to the existent preprocessing tools LiVer, NiVer, HyPre, blocked clause elimination (BCE), and Shatter with saucy 3.0. [ABSTRACT FROM AUTHOR]

ABSTRACT A compact I-shaped λ/2 resonator is introduced in order to reduce the mutual coupling between antenna elements and eliminate the scan blindness in a microstrip array. The proposed λ/2 resonator is inserted between the adjacent E-shaped microstrip antenna elements separated by 0.45 λ, as a technique to suppress the occurrence of radiation in the horizontal direction. Simulated and measured results show that a reduction in mutual coupling of 35 dB is obtained between elements at the operation frequency of 3.94 GHz of the array. The scan properties of microstrip array with and without resonator have been studied and the result indicates that the scan blindness of the array can be well eliminated because of the effect of the resonator. We have developed experimental models that have proved this concept of scan blindness elimination. Finally, the influence of other antenna parameters at the presence of resonator in the array system has been studied. Prototype antennas of two-element and four-element array with and without resonator have been fabricated, measured, and the idea has been verified. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:334-338, 2014 [ABSTRACT FROM AUTHOR]

The article presents a simpler approach in solving a system of linear equations, which includes the use of Chio's pivotal condensation process for computing determinants and Cramer's Rule. Topics discussed include the comparison of the substitution and elimination approach in solving a system of linear equations, a different point of view to look at substitution and elimination and the concept of Cramer's Rule.

Statistical engineering as proposed by Hoerl and Snee (2010a) aims to develop a discipline devoted to better understanding how to use statistical tools to support project goals. Existing examples abound but more work is needed. We discuss the use of statistical engineering to improve problem solving—that is, reducing variation in processes—and note that this requires a series of empirical investigations where we should use information gained to help plan subsequent investigations. The systematic use of prior/existing information, especially baseline information, in problem solving is illustrated using a crossbar dimension case study. The baseline results are used to help plan and analyze all subsequent investigations both when looking for a dominant cause of the variation and when assessing a possible solution. The effective use of prior statistical information and the consequences of its use in the variation reduction context are not commonly taught and thus opportunities for more efficient problem solving are lost. [ABSTRACT FROM AUTHOR]

This paper introduces new approaches for the analysis of frequent statement and dereference elimination for imperative and objectoriented distributed programs running on parallelmachines equipped with hierarchical memories.The paper uses languageswhose address spaces are globally partitioned. Distributed programs allow defining data layout and threads writing to and reading from other threadmemories. Three type systems (for imperative distributed programs) are the tools of the proposed techniques. Thefirst type systemdefines for every programpoint a set of calculated (ready) statements andmemory accesses.Thesecond type systemuses an enriched version of types of the first type system and determines which of the ready statements and memory accesses are used later in the program.Thethird type systemuses the information gather so far to eliminate unnecessary statement computations and memory accesses (the analysis of frequent statement and dereference elimination). Extensions to these type systems are also presented to cover object-oriented distributed programs. Two advantages of our work over related work are the following.The hierarchical style of concurrent parallel computers is similar to the memory model used in this paper. In our approach, each analysis result is assigned a type derivation (serves as a correctness proof). [ABSTRACT FROM AUTHOR]

Model structure selection is of crucial importance in radial basis function (RBF) neural networks. Existing model structure selection algorithms are essentially forward selection or backward elimination methods that may lead to sub-optimal models. This paper proposes an alternative selection procedure based on the kernelized least angle regression (LARS)–least absolute shrinkage and selection operator (LASSO) method. By formulating the RBF neural network as a linear-in-the-parameters model, we derive a l1-constrained objective function for training the network. The proposed algorithm makes it possible to dynamically drop a previously selected regressor term that is insignificant. Furthermore, inspired by the idea of LARS, the computing of output weights in our algorithm is greatly simplified. Since our proposed algorithm can simultaneously conduct model structure selection and parameter optimization, a network with better generalization performance is built. Computational experiments with artificial and real world data confirm the efficacy of the proposed algorithm. [ABSTRACT FROM AUTHOR]

A simple technique called the elimination method is proposed for calculation of the reflected and transmitted wave amplitudes in the case when two counterpropagating waves are incident on a multilayer structure with a step irregularity. The functioning of the method is exemplified by a structure consisting of ten media where the wave numbers are randomly distributed. The properties of the distribution of the reflected wave amplitude density that are due to the relationship between the structure's thickness and the minimum wavelength in it are revealed. It is shown that a disorder in the distribution of wave numbers in the interior of the structure reduces reflection, and a parameter quantitatively characterizing this reduction is proposed. [ABSTRACT FROM AUTHOR]

The Selective Harmonic Elimination Pulse Width Modulation technique (SHEPWM) is widely used for eliminating pre-selected lower order harmonics in multilevel inverters (MLI) output voltage with controlling the fundamental voltage component. The problem of roots solving of the set of transcendental nonlinear harmonic equations derived by Fourier analysis is addressed in many recent researches. The Newton Raphson (NR) method is limited used in case of multilevel inverter controlled by SHEPWM, due to the transcendental nature of the system set of equations and dependency of roots initial values. Modern optimization techniques such as Genetic Algorithm (GA) optimization are widely used in case of MLI controlled by SHEPWM. The main problem when using GA is how to find the switching angle patterns for a wide range of the modulation index (M). Which they eliminate pre-selected lower order harmonics and controlling the fundamental voltage component with minimum Total Harmonic Distortion (THD). In this paper a comprehensive study to obtain the required switching patterns which satisfy elimination pre-selected lower order harmonics at minimum THD from cascaded MLI output voltage controlled by SHEPWM was performed. The performance of cascaded multilevel inverter controlled by SHEPWM is compared based on calculating the required switching patterns using NR and GA methods. A significant improve in the obtained solution sets in a wide range of M in GA is achieved. In particular, it is shown that there are new solution sets which haven't been previously reported in literatures. Selected simulation and experimental results for 5, 7, 9 and 11 MLIs were reported to verify and to validate the theoretical findings. [ABSTRACT FROM AUTHOR]

This paper shows that for any given polynomial ideal the collection of Gröbner cones corresponding to -specific elimination orders forms a star-shaped region which contrary to first intuition in general is not convex. Moreover we show that the corresponding region may contain Gröbner cones intersecting in the boundary of the Gröbner fan in the origin only. This implies that Gröbner walks aiming for the elimination of variables from a polynomial ideal can be terminated earlier than previously known. We provide a slightly improved stopping criterion for a known Gröbner walk algorithm for the elimination of variables. [ABSTRACT FROM AUTHOR]

Abstract: In this report a method for common subexpression elimination in matrices is explored. The method is applied to several types of matrices occurring in numerical simulations. In all cases, the cost of a matrix–vector multiplication is reduced by a significant amount. The amount of storage required for the eliminated matrices is also less than that required for the original matrices. When the proposed method is applied to the Fourier transform matrix, the output is equivalent to the fast Fourier transform. For some matrices used in the fast multipole method for dislocation dynamics, the cost of a matrix–vector multiplication is reduced from to , where p is the expansion order. Using an expansion order of 5, one can expect a factor of four speedup of the fast multipole part of a dislocation dynamics code. [Copyright &y& Elsevier]

In an asymmetric rendezvous system, such as an unfair synchronous queue or an elimination array, threads of two types, consumers and producers, show up and are matched each with a unique thread of the other type. Here we present new highly scalable, high throughput asymmetric rendezvous systems that outperform prior synchronous queue and elimination array implementations under both symmetric and asymmetric workloads (more operations of one type than the other). Based on this rendezvous system, we also construct a highly scalable and competitive stack implementation. [ABSTRACT FROM AUTHOR]

The problem of resolution of singularities in positive characteristic can be reformulated as follows: fix a hypersurface $X$, embedded in a smooth scheme, with points of multiplicity at most $n$. Let an $n$-sequence of transformations of $X$ be a finite composition of monoidal transformations with centers included in the $n$-fold points of $X$, and of its successive strict transforms. The open problem (in positive characteristic) is to prove that there is an $n$-sequence such that the final strict transform of $X$ has no points of multiplicity $n$ (no $n$-fold points). In characteristic zero, such an $n$-sequence is defined in two steps. The first consists of the transformation of $X$ to a hypersurface with $n$-fold points in the so-called monomial case. The second step consists of the elimination of these $n$-fold points (in the monomial case), which is achieved by a simple combinatorial procedure for choices of centers. The invariants treated in this work allow us to present a notion of strong monomial case which parallels that of monomial case in characteristic zero: if a hypersurface is within the strong monomial case we prove that a resolution can be achieved in a combinatorial manner. [ABSTRACT FROM AUTHOR]

We design an algorithm to compute the Newton polytope of the resultant, known as resultant polytope, or its orthogonal projection along a given direction. The resultant is fundamental in algebraic elimination, optimization, and geometric modeling. Our algorithm exactly computes vertex- and halfspace-representations of the polytope using an oracle producing resultant vertices in a given direction, thus avoiding walking on the polytope whose dimension is α - n - 1, where the input consists of α points in ℤn. Our approach is output-sensitive as it makes one oracle call per vertex and per facet. It extends to any polytope whose oracle-based definition is advantageous, such as the secondary and discriminant polytopes. Our publicly available implementation uses the experimental CGAL package triangulation. Our method computes 5-, 6- and 7- dimensional polytopes with 35K, 23K and 500 vertices, respectively, within 2hrs, and the Newton polytopes of many important surface equations encountered in geometric modeling in < 1sec, whereas the corresponding secondary polytopes are intractable. It is faster than tropical geometry software up to dimension 5 or 6. Hashing determinantal predicates accelerates execution up to 100 times. One variant computes inner and outer approximations with, respectively, 90% and 105% of the true volume, up to 25 times faster. [ABSTRACT FROM AUTHOR]

By a sequence of rollings without slipping or twisting along segments of a straight line of the plane, a spherical ball of unit radius has to be transferred from an initial state to an arbitrary final state taking into account the orientation of the ball. We provide a new proof that with at most 3 moves, we can go from a given initial state to an arbitrary final state. The first proof of this result is due to Hammersley ( ). His proof is more algebraic than ours which is more geometric. We also showed that 'generically' no one of the three moves, in any elimination of the spin discrepancy, may have length equal to an integral multiple of 2π. [ABSTRACT FROM AUTHOR]

An efficient one-pot method for the regioselective bromination of allylic alcohol derivatives (two-step reaction sequence) followed by Sonogashira, Negishi, or Suzuki-Miyaura coupling reactions in the same reaction vessel (three-step reaction sequence) has been developed. The key reaction in these one-pot systems is the regioselective DBU-promoted trans HBr elimination of vicinal dibromides bearing an adjacent O-functional group. [ABSTRACT FROM AUTHOR]

In this paper, we present a simple strategy for the elimination of the translational kinetic energy contamination of the total energy in pre-Born–Oppenheimer calculations carried out in laboratory-fixed Cartesian coordinates (LFCCs). The simple expressions for the coordinates and the operators are thus preserved throughout the calculations, while the mathematical form and the parametrisation of the basis functions are chosen so that the translational and rotational invariances are respected. The basis functions are constructed using explicitly correlated Gaussian functions (ECGs) and the global vector representation. First, we observe that it is not possible to parametrise the ECGs so that the system is at rest in LFCCs and at the same time the basis functions are square integrable with a non-vanishing (positive-definite) norm. Then, we work out a practical strategy to circumvent this problem by making use of the properties of the linear transformation between the LFCCs and translationally invariant and centre-of-mass Cartesian coordinates as well as the transformation properties of the corresponding basis function parameter matrices. By exploiting these formal mathematical relationships, we can identify and separate the translational contamination terms in the matrix representation of the kinetic energy operator in the LFCC formalism. We present numerical examples for the translational contamination and its elimination for the two lowest rotational energy levels of the singlet hydrogen molecule, corresponding to para- and ortho-H2, respectively, treated as four-particle quantum systems. [ABSTRACT FROM AUTHOR]

Abstract: In the process of losing weight, the weight cycling, i.e., repeated bouts of the weight loss and regaining, can usually happen and be harmful to human. Thus it is very important to search for its mechanism, and more important is to keep the weight fixed and avoid weight cycling. Based on the recent developments, a geometric approach to global-stability problems is employed to obtain the conditions for the global asymptotic stability of the equilibrium in the human weight cycling model. The conditions are obtained to keep the weight stable without cycling. It means that, even though the food intake is large, if the metabolic efficiency is sufficiently small, then the weight cycling will be avoided and the aim to lose weight can be achieved. The above theoretical results are validated by employing the nonlinear dynamics software—WinPP. [Copyright &y& Elsevier]

To eliminate the signal trend terms, wavelet base functions are introduced for signal decomposition and reconstruction. The selection of wavelet bases may affect the result of eliminating signal trend. The concept of error index of signal trend elimination was proposed and the formula for calculating the index was presented. Using this formula, the error indexes of signal trend elimination of 34 types of wavelet bases were calculated. It was found that the wavelet bases of sym10 and other 5 types could be selected as preferred ones with less error indexes of signal trend elimination. Further, the sym10 and other two non-preferred wavelet bases were used to carry out the signal trend elimination of measured car body acceleration signal. The result shows that wavelet base of sym10 extracts the signal trend more precisely than other two non-preferred wavelet bases and the effectiveness of the presented formula for calculating the error index of signal trend elimination is validated [ABSTRACT FROM AUTHOR]

Abstract: In Gaussian elimination it is often desirable to preserve existing zeros (sparsity). This is closely related to perfect elimination schemes on graphs. Such schemes can be found in polynomial time. Gaussian elimination uses a pivot for each column, so opportunities for preserving sparsity can be missed. In this paper we consider a more flexible process that selects a pivot for each nonzero to be eliminated and show that recognizing matrices that allow such perfect partial elimination schemes is NP-hard. [Copyright &y& Elsevier]

A numerical method for solving the Cauchy problem for all the six Painlevé equations is proposed. The difficulty of solving these equations is that the unknown functions can have movable (that is, dependent on the initial data) singular points of the pole type. Moreover, the Painlevé III-VI equations may have singularities at points where the solution takes certain finite values. The positions of all these singularities are not a priori known and are determined in the process of solving the equation. The proposed method is based on the transition to auxiliary systems of differential equations in neighborhoods of the indicated points. The equations in these systems and their solutions have no singularities at the corresponding point and its neighborhood. Such auxiliary equations are derived for all Painlevé equations and for all types of singularities. Efficient criteria for transition to auxiliary systems are formulated, and numerical results illustrating the potentials of the method are presented. [ABSTRACT FROM AUTHOR]

The elimination tree model for sparse unsymmetric matrices and an algorithm for constructing it have been recently proposed by Eisenstat and Liu [SIAM J. Matrix Anal. Appl., 26 (2005), pp. 686-705] and [SIAM J. Matrix Anal. Appl., 29 (2008), pp. 1363-1381]. The construction algorithm has a worst-case time complexity of Θ(mn) for an n X n unsymmetric matrix having m off-diagonal nonzeros. We propose another algorithm that has a worst-case time complexity of ...(mlogn). We compare the two algorithms experimentally and show that both algorithms are efficient in general. The algorithm of Eisenstat and Liu is faster in many practical cases, yet there are instances in which there is a significant difference between the running time of the two algorithms in favor of the one proposed here. [ABSTRACT FROM AUTHOR]

Abstract: With many applications in engineering and scientific fields, quantifier elimination (QE) has received increasing attention. Cylindrical algebraic decomposition (CAD) is used as a basis for a general QE algorithm. In this paper we present an effective symbolic–numeric cylindrical algebraic decomposition (SNCAD) algorithm for QE incorporating several new devices, which we call “quick tests”. The simple quick tests are run beforehand to detect an unnecessary procedure that might be skipped without violating the correctness of results and they thus considerably reduce the computing time. The effectiveness of the SNCAD algorithm is examined in a number of experiments including practical engineering problems, which also reveal the quality of the implementation. Experimental results show that our implementation has significantly improved efficiency compared with our previous work. [Copyright &y& Elsevier]

RFID technologies are gaining much attention as they are attractive solutions to many applications. Localization based on active RFID technologies provides a much needed added-value to further expand the application domain. LANDMARC was the first attempt using active RFID for indoor location sensing with satisfactory results. However, the LANDMARC approach suffers from two drawbacks. First, it does not work well in a closed area with severe radio signal multi-path effects. Second, to further improve the localization accuracy, more reference tags are required which is costly and may trigger the RF interference phenomenon. The proposed VIRE approach can overcome the above drawbacks without any additional cost. Based on the concept of virtual reference tags, a proximity map is maintained by each reader. An elimination algorithm is used to eliminate those unlikely locations to reduce the estimation error. Our experimental results show that the new method consistently enhances the precision of indoor localization from 17 to 73 percent over the LANDMARC approach at different tag locations in different environments. [ABSTRACT FROM AUTHOR]

Abstract: One may represent polynomials not only by their coefficients but also by arithmetic circuits which evaluate them. This idea allowed in the past fifteen years considerable complexity progress in effective polynomial equation solving. We present a circuit based computation model which captures all known symbolic elimination algorithms in effective Algebraic Geometry and exhibit a class of simple elimination problems which require exponential size circuits to be solved in this model. This implies that the known, circuit based elimination algorithms are already optimal. [Copyright &y& Elsevier]

The first part of this article shows that qualitative comparative analysis (QCA)—also in its most recent form as in Ragin (2008)—does not correctly analyze data generated by causal chains. The incorrect modeling of data originating from chains essentially stems from QCA’s reliance on Quine-McCluskey optimization to eliminate redundancies from sufficient and necessary conditions. Baumgartner (2009a, 2009b) has introduced a Boolean methodology, termed coincidence analysis (CNA), which is related to QCA, yet, contrary to the latter, does not eliminate redundancies by means of Quine-McCluskey optimization. The second part of the article applies CNA to chain-generated data. It turns out that CNA successfully detects causal chains in small-n data. [ABSTRACT FROM AUTHOR]

This work addresses the inverse problems of expanded motion and path generation for the spatial (revolute–revolute–spherical–spherical, RRSS) linkage and the 4R spherical linkage with order and branch elimination. Two constrained non-linear equation systems are presented in this work for RRSS and 4R spherical motion and path generation with order and branching constraints. Both equation systems include the spatial four-link displacement model (by Suh and Radcliffe) as an objective function along with order and branching inequality constraints. As examples, both a branch defect-free and order defect-free RRSS linkage 4R spherical linkage are synthesized to approximate expanded groups of precision positions. [ABSTRACT FROM PUBLISHER]

Multivariate polynomials are usually discussed in the framework of algebraic geometry. Solving problems in algebraic geometry usually involves the use of a Gröbner basis. This article shows that linear algebra without any Gröbner basis computation suffices to solve basic problems from algebraic geometry by describing three operations: multiplication, division, and elimination. This linear algebra framework will also allow us to give a geometric interpretation. Multivariate division will involve oblique projections, and a link between elimination and principal angles between subspaces (CS decomposition) is revealed. The main computational tool in this approach is the QR decomposition. [ABSTRACT FROM AUTHOR]

We present an advanced design methodology for pulse-width-modulated (PWM) DC-AC signal generation. Using design methods based on the Walsh transform, AC sinusoidal signals can be approximated by suitable PWM signals. For different AC amplitudes, the switching instants of the PWM signals can be efficiently computed by using appropriate systems of explicit linear equations. However, the equation systems provided by conventional implementations of this approach are typically only valid for a restricted interval of AC amplitudes and, in general, a supervised implementation of several equation systems is necessary to cover the full AC amplitude range. Additionally, obtaining suitable equation systems for designs with a large number of switching instants requires solving a complex optimization problem. In defining the constitutive pulses of a PWM signal, a suitable partition of the time interval is used as a reference system. In the new methodology, pulses are chosen to be symmetric with respect to the partition points, and the switching times are specified by means of switching ratios with respect to the endpoint subintervals. This approach leads to particularly simple Walsh series representations, introduces a remarkable computational simplification, and achieves excellent results in reducing the harmonic distortion. [ABSTRACT FROM AUTHOR]

SUMMARY The most efficient way to parallelize computation is to build and evaluate the task graph constrained only by the data dependencies between the tasks. Both Intel's C++ Concurrent Collections (CnC) and Threading Building Blocks (TBB) libraries allow such task-based parallel programming. CnC also adapts the macro data flow model by providing only single-assignment data objects in its global data space. Although CnC makes parallel programming easier, by specifying data flow dependencies only through single-assignment data objects, its macro data flow model incurs overhead. Intel's C++ CnC library is implemented on top of its C++ TBB library. We can measure the overhead of CnC by comparing its performance with that of TBB. In this paper, we analyze all three types of data dependencies in the tiled in-place Gauss-Jordan elimination algorithm for the first time. We implement the task-based parallel tiled Gauss-Jordan algorithm in TBB using the data dependencies analyzed and compare its performance with that of the CnC implementation. We find that the overhead of CnC over TBB is only 12 %- 15 % of the TBB time, and CnC can deliver as much as 87 %- 89 % of the TBB performance for Gauss-Jordan elimination, using the optimal tile size. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: We re-consider perfect elimination digraphs, that were introduced by Haskins and Rose in 1973, and view these graphs as directed analogues of chordal graphs. Several structural properties of chordal graphs that are crucial for algorithmic applications carry over to the directed setting, including notions like simplicial vertices, perfect elimination orderings, and vertex layouts. We show that semi-complete perfect elimination digraphs are also characterised by a set of forbidden induced subgraphs resemblant of chordless cycles. Moreover, just as the chordal graphs are related to treewidth, the perfect elimination digraphs are related to Kelly-width. [Copyright &y& Elsevier]

A new feature selection method based on clustering algorithm is proposed to selected informative features. First, category-unrelated features are kicked out according to Bhattacharyya distance. Then, based on the process of recursive feature elimination, a weighted distance between sample and the cluster center generated by the fuzzy interactive self-organizing data algorithm (ISODATA) is used as the index of feature for separating different classes. Finally, the candidate feature subset with the maximum area under the receiver operating characteristic curve (AUC) value and accuracy rate both in classification and clustering tests is selected as the optimal feature subset. The proposed feature subset selection method is applied to five gene expression profile datasets and experiment results show that the selected features have good performance in terms of both classification and clustering measurements. Results demonstrate that the proposed method is effective for selecting informative features from high-dimensional dataset. [ABSTRACT FROM AUTHOR]

Abstract: For some modal fixed point logics, there are deductive systems that enjoy syntactic cut-elimination. An early example is the system in Pliuskevicius (1991) for LTL. More recent examples are the systems by the authors of this paper for the logic of common knowledge (Brünnler and Studer, 2009) and by Hill and Poggiolesi (2010) for PDL, which are based on a form of deep inference. These logics can be seen as fragments of the modal mu-calculus. Here we are interested in how far this approach can be pushed in general. To this end, we introduce a nested sequent system with syntactic cut-elimination which is incomplete for the modal mu-calculus, but complete with respect to a restricted language that allows only fixed points of a certain form. This restricted language includes the logic of common knowledge and PDL. There is also a traditional sequent system for the modal mu-calculus by Jäger et al. (2008) , without a syntactic cut-elimination procedure. We embed that system into ours and vice versa, thus establishing cut-elimination also for the shallow system, when only the restricted language is considered. [Copyright &y& Elsevier]

Abstract: Proof search has been used to specify a wide range of computation systems. In order to build a framework for reasoning about such specifications, we make use of a sequent calculus involving induction and co-induction. These proof principles are based on a proof-theoretic (rather than set-theoretic) notion of definition (Hallnäs, 1991 [18], Eriksson, 1991 [11], Schroeder-Heister, 1993 [38], McDowell and Miller, 2000 [22]). Definitions are akin to logic programs, where the left and right rules for defined atoms allow one to view theories as “closed” or defining fixed points. The use of definitions and free equality makes it possible to reason intensionally about syntax. We add in a consistent way rules for pre- and post-fixed points, thus allowing the user to reason inductively and co-inductively about properties of computational system making full use of higher-order abstract syntax. Consistency is guaranteed via cut-elimination, where we give a direct cut-elimination procedure in the presence of general inductive and co-inductive definitions via the parametric reducibility technique. [Copyright &y& Elsevier]