Impact of performance considerations on formal specification design

Different client applications of a given functional behaviour usually have different performance requirements. Designing a formal interface specification of the functional behaviour to allow for alternative implementations, and hence, to be suitable for clients with varying performance requirements, is a challenging task. The specifier must consider ramifications of alternative designs on performance to produce a truly implementation-neutral (and hence, performance-neutral) functionality specification. This paper illustrates the influence of performance-both duration and capacity — considerations using a case study in object-based software specification. When these considerations are combined with concerns for comprehensibility and full abstraction, specifications that result that are arguably among the most desirable.     

Sliding wear studies in glass-epoxy system through scanning microscopic observations

The work reports the wear occurring in a glass-epoxy composite system as a function of sliding distance for a constant sliding velocity and applied load. It is seen that the weight loss increases with increasing distance, but the gradient maintained all through is not the same. An attempt has therefore been made to correlate the weight loss with the scanning microscopic observations on the worn surfaces. It is found that in the early part, the wear of the resin/mat layer contributes to the phenomenon. The process of breakage of fibre into fragments and the resin debris formation accounts for the wear at a much later stage. The phenomenon occurring in between these two stages, is attributed to some of the broken fibres getting lodged in the matrix and agglomeration of the debris formed from the matrix material. Other features of interest are highlighted and discussed in this report.     

One-multiplier adaptive lattice algorithm for recursive filters

The formulation of one-multiplier lattice structures of the Gray-Markel type forinfinite impulse response filters is reviewed. Several special cases of this formulation — including the well-known Gray-Markel normalized lattice—are presented as scaled polynomial versions of the two-multiplier lattice. A new adaptive algorithm is presented for updating the parameters of one-multiplier lattice structured recursive filters. The LMS-based algorithm requires fewer computations than earlier reported algorithms [1]–[4].The research reported here was conducted with funds administered by the Naval Postgraduate School research council.     

Kinetics of electrophoretic deposition ofβ-alumina

The equations describing electrophoretic deposition, proposed by Hamakar Avgustinik and coworkers, have been verified in the case ofβ-alumina suspended in isoamyl alcohol. The variation of electrophoretic yield with (i) concentration of suspension, (ii) extent of grinding the suspension, (iii) temperature of the suspension, and (iv) electrode separation was studied. The effect of addition of glycol monethyl ether was also investigated. The effect of various parameters on the electrical conductivity of the suspension, which in turn influences the yield, was noted.     

Radial cavity-fed spatial power combiner with retrodirective array behavior

This paper discusses the design and operational properties of a circular array of slot coupled active GaAs metal-semiconductor field-effect transistor (MESFET) rectangular microstrip patch antennas arranged for quasioptical power combining at X band. The active antenna radiating elements are injection locked by slot coupling to a radial cavity waveguide. Spatial power combining efficiency of 75% and dc to radio frequency (RF) conversion efficiency of 10% at 28 dBm EIRP was achieved at 10.38 GHz. Retrodirective action was also demonstrated by using the active elements as self-oscillating mixers pumped at 20.76 GHz.     

Perspective Geometry Based Single Image Camera Calibration

This paper presents a novel method for 3D camera calibration. Calculation of the focal length and the optical center of the camera are the main objectives of this research work. The proposed technique requires a single image having two vanishing points. A rectangular prism is employed as the calibration target to generate vanishing points. The special arrangement of the calibration object adds more accuracy in finding the intrinsic parameters. Based on the geometry of the perspective distortion of the edges of the prisms from the image, vanishing points are found. There on, fixing up the picture plane followed by fixing up of the station point is carried out based on the relations that are formulated. Experimental results of our method are likened with Zhang’s method. Results are tabulated to show the accuracy of the proposed approach.

Autonomous exploration using rapid perception of low-resolution image information

We present a technique for mobile robot exploration in unknown indoor environments using only a single forward-facing camera. Rather than processing all the data, the method intermittently examines only small 32×24 downsampled grayscale images. We show that for the task of indoor exploration the visual information is highly redundant, allowing successful navigation even using only a small fraction of the available data. The method keeps the robot centered in the corridor by estimating two state parameters: the orientation within the corridor, and the distance to the end of the corridor. The orientation is determined by combining the results of five complementary measures, while the estimated distance to the end combines the results of three complementary measures. These measures, which are predominantly information-theoretic, are analyzed independently, and the combined system is tested in several unknown corridor buildings exhibiting a wide variety of appearances, showing the sufficiency of low-resolution visual information for mobile robot exploration. Because the algorithm discards such a large percentage of the pixels both spatially and temporally, processing occurs at an average of 1000 frames per second, thus freeing the processor for other concurrent tasks.     

Hybrid genetic algorithm and association rules for mining workflow best practices

Business workflow analysis has become crucial in strategizing how to create competitive edge. Consequently, deriving a series of positively correlated association rules from workflows is essential to identify strong relationships among key business activities. These rules can subsequently, serve as best practices. We have addressed this problem by hybridizing genetic algorithm with association rules. First, we used correlation to replace support-confidence in genetic algorithm to enable dynamic data-driven determination of support and confidence, i.e., use correlation to optimize the derivation of positively correlated association rules. Second, we used correlation as fitness function to support upward closure in association rules (hitherto, association rules support only downward closure). The ability to support upward closure allows derivation of the most specific association rules (business model) from less specific association rules (business meta-model) and generic association rules (reference meta-model). Downward closure allows the opposite. Upward-downward closures allow the manager to drill-down and analyze based on the degree of dependency among business activities. Subsequently, association rules can be used to describe best practices at the model, meta-model and reference meta-model levels with the most general positively dependent association rules as reference meta-model. Experiments are based on an online hotel reservation system.