Adaptive set-membership identification in O(m)time for linear-in-parameters models

Some fundamental contributions to the theory and applicability of optimal bounding ellipsoid (OBE) algorithms for signal processing are described. All reported OBE algorithms are placed in a general framework that demonstrates the relationship between the set-membership principles and least square error identification. Within this framework, flexible measures for adding explicit adaptation capability are formulated and demonstrated through simulation. Computational complexity analysis of OBE algorithms reveals that they are of O(m²) complexity per data sample with m the number of parameters identified. Two very different approaches are described for rendering a specific OBE algorithm, the set-membership weighted recursive least squares algorithm, of O(m) complexity. The first approach involves an algorithmic solution in which a suboptimal test for innovation is employed. The performance is demonstrated through simulation. The second method is an architectural approach in which complexity is reduced through parallel competition     

Efficient algorithm for reliability of a circular consecutive-k-out-of-n:F system

The time complexities of previously published algorithms for circular consecutive-k-out-of-n:F systems are O (nk²) and O(nk). The authors propose a method to improve the original O(nk² ) algorithm, and hence derive an O(nk) algorithm     

An O(kn) algorithm for a circularconsecutive-k-out-of-n:F system

An O(k×n) algorithm is described for evaluating the reliability of a circular consecutive-k-out- n:F system     

Reliability of linear and circular consecutively-connected systems

J.G. Shanthikumar (IEEE Trans. Reliability, vol.R-36, p.546-50, Dec. 1987) proposed a new system structure called the consecutively connected system, which is a generalization of the well-studied consecutive-k-out-of-n:F system. An O(n ²) algorithm was developed for its reliability evaluation. This work studies the structure of the consecutively connected system and provides more efficient algorithms for its reliability evaluation. The complexities of the algorithms are of order O(kn) for linear systems and O(k³n) for circular systems (k <n). The concepts of transmitting capability and receiving capability are introduced     

Gain measurements on the KrF(B→X), XeF(B→X), and XeF(C→A) lasertransitions in an XeF(C→A) laser gas mixture

Optimum energy extraction from an electron-beam-pumped XeF(C →A) laser is achieved with a five-component rare gas halide mixture. The characterization and modeling of laser action in such a gas mixture requires a knowledge of small-signal gain and absorption coefficients not only on the blue-green XeF(C→ A) transition, but also in the ultraviolet (UV) region for the competing XeF(B→X) and KrF(B→X ) transitions. The authors report gain measurements on the XeF(C→A) transition and small-signal gain and absorption coefficients at or near both the XeF(B→X ) (351 and 353 nm) and KrF(B→X) (248 nm) transitions. A study of the gain for the UV and visible transitions as a function of Kr and Xe partial pressure is reported, and its impact on the XeF(C→A) kinetics is discussed     

Recursive T-matrix algorithms for the solution ofelectromagnetic scattering from strip and patch geometries

Two recursive T-matrix algorithms are presented and their reduced computational complexities and reduced memory requirements are demonstrated. These algorithms are applied to the problem of electromagnetic scattering from conducting strips and patches with canonical geometries. The geometries are reminiscent of finite-sized frequency selective surfaces. Computational complexities of O( N²) and O(N^7/3) and memory requirements of O(N) and O(N ^4/3) are shown to be feasible for two-dimensional and three-dimensional geometries, respectively. The formulation uses only two components of the electric field. Therefore, the vector electromagnetic problem of scattering from three-dimensional patch geometries can be solved using scalar addition theorems for spherical harmonic wave functions. For a two-dimensional strip problem, both TM and TE polarizations can be solved simultaneously using this formulation. Numerical scattering results in the form of radar cross sections (RCS) are validated by comparison with the method of moments     

A nonsorting VLSI structure for implementing the (M, L) algorithm

A nonsorting structure for implementing the (M, L) algorithm is presented. The processing is based on a survivor selection operation that incorporates parallelism and has an execution time proportional to the product of the logarithm of bM (the number of contender paths), and k (the number of bits used for path metrics). Aside from the path extender(s), the processor area is only a small fraction of the total chip area; most is simply for required storage of path histories and metrics. This means that the structure can support a large M on a single chip. In addition, the structure can be extended to larger M by stacking rows of a few different types of custom chips     

Relationships between m-sequences over GF(q) andGF(qm)

It is shown that m-sequences over GF(q^m ) of length q^nm-1 corresponding to primitive polynomials in GF[q^m,x] of degree n can be generated from known m-sequences over GF(q) of length q^nm-1 obtained from primitive polynomials in GF[q,x] of degree mn. A procedure for generating the m-sequences over GF(q²) from m-sequences over GF(q) was given which enables the generation of m-sequences over GF( p²ⁿ). In addition it was shown that all of the primitive polynomials in GF[q,^m,x] can be obtained from a complete set of the primitive polynomials in GF[q ,x]     

Effective recursive algorithm for computing multiplicative inversesin GF(2m)

Presents an effective recursive algorithm for computing multiplicative inverses in GF(2^m), where m=2^k, employing normal bases. The proposed algorithm requires m-1 cyclic shifts and two multiplications in GF (2^m) and in each subfield of GF(2^m): GF(2^m/2), GF(2^m/4),. . ., GF (2⁸) and GF(2⁴)     

An efficient non-recursive algorithm for computing the reliabilityof k-out-of-n systems

An algorithm for computing the reliability of k-out-of- n systems is proposed. It is simple, easy to implement on a computer, time and memory efficient, and good for numerical computation. The memory complexity is O(n-k), and for a given value of n-k the computation time is proportional to n . Its FORTRAN implementation is presented     

The (d,k) subcode of a linear block code

A simple technique employing linear block codes to construct (d,k) error-correcting block codes is considered. This scheme allows asymptotically reliable transmission at rate R over a BSC channel with capacity C_BSC provided R ⩽C_d,k-(1+C_BSC), where C_d,k is the maximum entropy of a (d,k ) source. For the same error-correcting capability, the loss in code rate incurred by a multiple-error correcting (d,k) code resulting from this scheme is no greater than that incurred by the parent linear block code. The single-error correcting code is asymptotically optimal. A modification allows the correction of single bit-shaft errors as well. Decoding can be accomplished using off-the-shelf decoders. A systematic (but suboptimal) encoding scheme and detailed case studies are provided     

Correlation between 1/f noise and hFElong-term instability in silicon bipolar devices

Accelerated life tests with high-temperature storage and electric aging for n⁺-p-n silicon planar transistors were carried out. Current gain h_FE increases monotonously with time during the tests, and the h_FE drift is correlated with initial measured 1/f noise in the transistors, i.e. the drift amount significantly increases with the increase of noise level. The correlation coefficient of relative drift Δh_FE /h_FE and 1/f noise spectral density S_iB(f) is far larger than that of Δ h_FE/h_FE and initial DC parameters of the transistors. A quantitative theory model for the h _FE drift has been developed and explains the h _FE drift behavior in the tests, which suggests that the h _FE drift and 1/f noise can be attributed to the same physical origin, and both are caused by the modulation of the oxide traps near the Si-SiO₂ interface to Si surface recombination. 1/f noise measurement, therefore, may be used as a fast and nondestructive means to predict the long-term instability in bipolar transistors     

Confidence bounds for Pr{X>Y} in 1-way ANOVArandom model

Approximate confidence bounds for reliability, R=Pr{X >Y|X,Y}, are obtained, where X and Y are independent normal (Gaussian) random variables, and X and Y are vectors of measurements for X and Y, respectively. Balanced 1-way ANOVA (analysis of variants) random effect models are assumed for the populations of X and Y. Confidence bounds are derived for R under three cases for standard deviations, σ_x and σ_y. An example shows how the results are used     

Closest coset decoding of |u|u+v| codes

The general concept of closest coset decoding (CCD) is presented, and a soft-decoding technique for block codes that is based on partitioning a code into a subcode and its cosets is described. The computational complexity of the CCD algorithm is significantly less than that required if a maximum-likelihood detector (MLD) is used. A set-partitioning procedure and details of the CCD algorithm for soft decoding of |u|u+v| codes are presented. Upper bounds on the bit-error-rate (BER) performance of the proposed algorithm are combined, and numerical results and computer simulation tests for the BER performance of second-order Reed-Muller codes of length 16 and 32 are presented. The algorithm is a suboptimum decoding scheme and, in the range of signal-to-noise-power-density ratios of interest, its BER performance is only a few tenths of a dB inferior to the performance of the MLD for the codes examined     

Bounds for reliability of consecutivek-within-m-out-of-n:F systems

Upper and lower bounds for the reliability of a (linear or circular) consecutive k-within-m-out-of-n:F system with unequal component-failure probabilities are provided. Numerical calculations indicate that, for systems with components of good enough reliability, these bounds quite adequately estimate system reliability. The estimate is easy to calculate, having computational complexity O(m²×n). For identically distributed components, a Weibull limit theorem for system time-to-failure is proved     

A technique for real-time measurement of Nth-orderderivativesdNV/dIN

A technique for the measurement of device derivatives d ^NV/dI^N of arbitrary order N described. Measurement is accomplished by injecting a test current composed of the sum of N square waves into the rest device, and then multiplying the corresponding voltage change by the product of those same square waves, followed by low-pass filtering. The algorithm is implemented in real time using a mixture of analog and digital circuitry, and its application to semiconductor laser control in high-speed optical communications is described     

Robustness of mean E{X} and R charts

The effect of nonnormality on E{X} and R charts is reported. The effect of departure from normality can be examined by comparing the probabilities that E{X} and R lie outside their three-standard-deviation and two-standard-deviation control limits. Tukey's λ-family of symmetric distributions is used because it contains a wide spectrum of distributions with a variety of tail areas. The constants required to construct E{X} and R charts for the λ-family are computed. Control charts based on the assumption of normality give inaccurate results when the tails of the underlying distribution are thin or thick. The validity of the normality assumption is examined by using a numerical example     

On (k, t)-subnormal covering codes

The concept of a (k, t)-subnormal covering code is defined. It is discussed how an amalgamated-direct-sumlike construction can be used to combine such codes. The existence of optimal (q, n, M) 1 codes C is discussed such that by puncturing the first coordinate of C one obtains a code with (q, 1)-subnorm 2     

The performance of depressed-cladding single-mode fibers withdifferent b/a ratios

Depressed-cladding single-mode fibers with a first cladding-to-core ratio (b/a) ranging from seven to one and relative refractive-index differences of the core from 0.25 to 0.35% and of the cladding from 0 to -0.2% are investigated experimentally with respect to the LP₁₁ mode cutoff properties, the mode-field diameter, the dispersion, and the bending attenuation. Numerical calculations based on actual profile parameters of the bend loss and the mode-field diameter agree well with experiment. It is demonstrated that low attenuation and bend losses independent of b/a can be obtained if the cutoff wavelength is kept constant by adjusting the core radius, the core index or the index of the first cladding