Alternative to the karatsuba algorithm for software implementations of GF(2n) multiplications

A new approach to subquadratic space complexity GF(2ⁿ) multipliers has been proposed recently. The corresponding algorithm for software implementations is developed. While its recursive implementation is as simple as that of the Karatsuba algorithm, it requires much less memory to store the look-up table. Therefore it is quite suitable for memory-constrained applications, for example smart cards.     

Parallel unidirectional division algorithms and implementations parallel unidirectional division algorithms and implementations

Abstract

This paper describes the design of algorithms for unidirectional division. Rather than the conventional, restoring or nonrestoring, divisions which require both subtraction and addition operations, alternately, during the process of division, the proposed method needs only one direction, either subtraction or addition, but not both, during the process of the division. If both operands, dividend and divisor, are positive or negative, only subtraction is used. However, if one is positive and the other negative, only addition is applied. This method can skip zero bits in dividend, and consequently the number of additions/subtractions is expected to be less than conventional division, about (3/5)n compared to 3/2n (or n if MUXes are used) for restoring or to n for nonrestoring. In addition, unidirectional division can be processed in parallel or in semi‐parallel, if the bit length of the dividend is long enough. This method is also easily extended to apply to two's complement divisions. The conversion of the quotient to binary is not required for the proposed method, (in which nonrestoring division is necessarily converted back to binary code in order to match other operations, because the resulting quotient is expressed by signed‐digit code).     

Chaos computing: ideas and implementations

We review the concept of the 'chaos computing' paradigm, which exploits the controlled richness of nonlinear dynamics to obtain flexible reconfigurable hardware. We demonstrate the idea with specific schemes and verify the schemes through proof-of-principle experiments.     

Design and efficient implementations of predictive FIR filters

Two new approaches to the design of predictive FIR filters are presented. First, we discuss the design of predictors and estimators for narrow-band signals based on the interpolated FIR (IFIR) filter approach. The transfer function of the IFIR predictor is of the form H(z)=P(z^L)G(z) where P(z) is a predictor and G(z) is an interpolating estimator. The general-purpose design procedure for efficient IFIR predictors is described, and demonstrated for polynomial predictors. The resulting predictors, optimized for white noise attenuation, have much lower computational complexity than the corresponding direct-form FIR predictors. Secondly, an IIR filter-based implementation of sinusoidal FIR predictors is presented. As an application, a zero-crossing detector for 50 Hz thyristor drives is designed     

Theory of constraints-based methodology for effective ERP implementations

The benefits as well as the turmoil that the implementation of enterprise resource planning (ERP) systems creates for multinational companies are well known. Several reports and evidence through case studies underline both the difficulties and the resulting benefits of ERPs. This paper addresses the reasoning behind long implementation times and organizational thunderstorms that tantalise the deployment of ERP systems. It focuses on two aspects of most implementation projects that generate the majority of technical and functional problems and constitute the projects’ bottleneck, i.e. code development within ERP systems due to key and unique requirements in a business environment, and localization and reporting needs that companies must adhere to or want to achieve. The approach proposes the classification of functional requirements into business critical and legally necessary, and the distribution of code development for system not fully supported processes among these two classes is discussed. Subsequently, the implementation times and deployment inefficiencies are coupled with the level of code development, and the difficulty of avoiding this for the two requirements’ classes, mainly due to user inflexibility and local environment peculiarities, is discussed. Using the Theory of Constraints, a coherent methodology for handling bottlenecks and effectively planning the code development effort is proposed, and trade-offs are derived between successful and on-time ERP implementations with managerial enforcement of best practices fully functional within major ERP systems. The approach is verified through field data from an actual SAP R/3 implementation at the largest manufacturer of packaging products and equipment in Europe.     

VLSI implementations of efficient isotropic flexible 2D convolvers

A new 2D isotropic convolver designed to operate on 256 grey-level images is presented. When realised by using 90 nm IV CMOS technology, the core of the proposed circuit exhibits a 1.25-GHz running frequency with an average power dissipation of only sime1 mW/MHz. The new convolver can also be efficiently realised using FPGAs.     

On the effect of linear algebra implementations in real-time multibody system dynamics

This paper compares the efficiency of multibody system (MBS) dynamic simulation codes that rely on different implementations of linear algebra operations. The dynamics of an N-loop four-bar mechanism has been solved with an index-3 augmented Lagrangian formulation combined with the trapezoidal rule as numerical integrator. Different implementations for this method, both dense and sparse, have been developed, using a number of linear algebra software libraries (including sparse linear equation solvers) and optimized sparse matrix computation strategies. Numerical experiments have been performed in order to measure their performance, as a function of problem size and matrix filling. Results show that optimal implementations can increase the simulation efficiency in a factor of 2–3, compared with our starting classical implementations, and in some topics they disagree with widespread beliefs in MBS dynamics. Finally, advices are provided to select the implementation which delivers the best performance for a certain MBS dynamic simulation.     

Comparing implementations of global and local indicators of spatial association

Functions to calculate measures of spatial association, especially measures of spatial autocorrelation, have been made available in many software applications. Measures may be global, applying to the whole data set under consideration, or local, applying to each observation in the data set. Methods of statistical inference may also be provided, but these will, like the measures themselves, depend on the support of the observations, chosen assumptions, and the way in which spatial association is represented; spatial weights are often used as a representational technique. In addition, assumptions may be made about the underlying mean model, and about error distributions. Different software implementations may choose to expose these choices to the analyst, but the sets of choices available may vary between these implementations, as may default settings. This comparison will consider the implementations of global Moran’s I, Getis–Ord G and Geary’s C, local \(I_i\) and \(G_i\), available in a range of software including Crimestat, GeoDa, ArcGIS, PySAL and R contributed packages.     

A comparison of approaches and implementations for automating decision analysis

This paper describes and compares three formal methods and software implementations for solving decision analysis problems. The comparison includes decision trees, influence diagrams, and a new approach developed by the authors that combines features of trees and influence diagrams. The new approach introduces a language for expressing decision analysis problems and an efficient solution algorithm that exploits structural properties of decision analysis problems. These features allows decision analysis problems to be represented compactly and to be solved very efficiently.     

Free-space optical shuffle implementations by use of birefringence-customized modular optics

A stacked integration technique based on polarization optics is studied for implementing shuffle-based interconnection networks with three-dimensional solid-state modules. A basic building block of the proposed scheme consists of a hole-patterned half-wave retarder for birefringence customizations and a calcite slab for subsequent beam deflections. On the basis of a cascade of such building blocks the submodules of various shuffle-family permutations can be implemented. To minimize channel cross talk, we incorporated a collimating-relaying imaging system. To help design birefringence customization, we developed algebraic formulations of folded shuffle operations using separable shuffles. Proof-of-concept experimental results, as well as system design, fabrication, and integration issues, are discussed.     

Alternative interpretation of the edge-diffraction phenomenon

An alternative interpretation of the phenomenon of edge diffraction is proposed according to a new separation of the Fresnel function. The subfields are investigated in the problem of diffraction of a plane wave by a perfectly conducting half-plane, and the results are compared numerically with other interpretations.     

Efficient and side-channel-aware implementations of elliptic curve cryptosystems over prime fields

Elliptic curve cryptosystems (ECCs) are utilised as an alternative to traditional public-key cryptosystems, and are more suitable for resource-limited environments because of smaller parameter size. In this study, the authors carry out a thorough investigation of side-channel attack aware ECC implementations over finite fields of prime characteristic including the recently introduced Edwards formulation of elliptic curves. The Edwards formulation of elliptic curves is promising in performance with built-in resiliency against simple side-channel attacks. To our knowledge the authors present the first hardware implementation for the Edwards formulation of elliptic curves. The authors also propose a technique to apply non-adjacent form (NAF) scalar multiplication algorithm with side-channel security using the Edwards formulation. In addition, the authors implement Joye's highly regular add-always scalar multiplication algorithm both with the Weierstrass and Edwards formulation of elliptic curves. Our results show that the Edwards formulation allows increased area-time performance with projective coordinates. However, the Weierstrass formulation with affine coordinates results in the simplest architecture, and therefore has the best area-time performance as long as an efficient modular divider is available.     

Successful implementations of MES in Korean manufacturing SMEs: an empirical study

This study explores the factors that affect the successful implementation of the Manufacturing Execution Systems (MES) in small and medium manufacturing enterprises (SMMEs). To this end, a survey was carried out. Responses from 163 SMMEs were analysed. The results found that all hypothesised variables including top management support, sufficiency of investment, capacity of the system developer, and user participation were critical factors for successful MES implementation in SMMEs. This study is the first empirical study on the successful implementation of MES in SMMEs in the Asia/Pacific region.     

Two implementations of IRK integrators for real‐time multibody dynamics

Recently, several authors have proposed the use of implicit Runge–Kutta (IRK) integrators for the dynamics of multibody systems. On the other hand, Newmark‐type or structural integrators have shown to be appropriate when real‐time performance is demanded in that field. Therefore, the following question arises: might the IRK integrators be suitable for real‐time purposes? And, provided the answer is positive: might they be preferable to the Newmark‐type family? This paper reports an investigation which has been conducted by the authors in order to get insight into the two questions formulated above. Since, based on previous experiences, it can be suspected that the performance of the integrators may be dependent on the type of dynamic formulation applied, the following three formulations have been considered for the study: a global penalty formulation in dependent natural co‐ordinates (many constraints), a topological semi‐recursive penalty formulation in dependent relative co‐ordinates (few constraints), and a topological semi‐recursive formulation in independent relative co‐ordinates (no constraints). As representative of the IRK family, a two‐stage SDIRK integrator has been selected due to its low associated computational burden, while, on the side of the structural integrators, the trapezoidal rule has been chosen. Two alternative implementations have been proposed to combine the dynamic formulations and the SDIRK integrator. A very demanding maneuver of the whole model of a vehicle has been simulated through all the possible combinations dynamic‐formulation/integrator, for different time‐steps. Conclusions have been drawn based on the obtained results, which provide some practical criteria for those interested in achieving real‐time performance for large and complex multibody systems. Copyright © 2005 John Wiley & Sons, Ltd.     

Alternative analytical forms of the Fuchs-Sondheimer function

Starting from the Cottey conduction model and its extension, it is shown that the Fuchs-Sondheimer functions can be approximated by the extended Cottey function at any reduced thickness, provided that the specular electronic reflection coefficient,p, takes values larger than 0.31. Whatever the values ofp and the film thickness be an analytical formulation (in the form of the Cottey function) is proposed for an accurate approximation of the Fuchs-Sondheimer function. Moreover, it is suggested that the scattering processes defined in the Fuchs-Sondheimer model have no interaction.     

A competitive progression perspective of JIT systems: evidence from early US implementations

This study investigates the holistic implementation of just-in-time (JIT) manufacturing. We contend that the most important elements of holistic JIT systems – focused factory, reduced setup times, group technology, total productive maintenance, multifunction employees, uniform workload, just-in-time purchasing, Kanban, total quality control and quality circles – should be implemented in a sequential manner for a firm to reap sustainable operational gains. The right sequence of implementation of JIT practices is derived using the theory of competitive progression and based on four JIT practice bundles – conformance quality related practices, delivery reliability related practices, volume flexibility related practices and low cost related practices. Data collected in a cross-sectional field study of US manufacturers are used to test the suggested implementation sequence of JIT practices and the impact of the JIT practice bundles on improvement in non-value added performance. The results indicate that implementations of JIT management practices should be in the order – first, conformance quality related practices; second, delivery reliability related practices; third, volume flexibility related practices and; finally low cost related practices. In addition, significant improvement in operational performance, as reflected in improvement of non-value added performance, is achieved via the cumulative capability building.     

Alternative DRM formulations

In this paper, we present two DRM formulations. For a pseudo-Poisson equation, if the right-hand side is a linear operation on the dependent variable, we can derive a new DRM formulation. In comparison with the traditional DRM formulation for the same equation, the proposed approach is much easier and more efficient. For the axisymmetric Poisson equation, we construct a DRM formulation by using the linear axisymmetric radial basis function. The particular solution involved is obtained in a closed form, and thus speeds up the evaluation of the particular solution. Three numerical examples demonstrate the accuracy and efficiency of these formulations.     

Alternative method of describing the kinetics of crystallization

We present a comparative analysis of a macrokinetic type equation and the AvramiKolmogorov equation for describing the crystallization of polymers. We show that the macrokinetic equation agrees with experiment over the whole range of the degrees of transformations.Translated from InzhenernoFizicheskii Zhurnal, Vol. 46, No. 1, pp. 124–128, January, 1984.