Statistical separability of spectral classes of blighted corn

The purpose of this study was to determine the statistical separability of multispectral measurements from corn having varying levels of southern corn leaf blight severity. Multispectral scanner data in twelve spectral channels in the wavelength range 0.4 to 11.7 μm were analyzed for ten selected flightlines of the 1971 Corn Blight Watch Experiment. A total of 168 corn fields having 18,804 sample points were analyzed. The blight rating information for these fields was available from ground observations. Maximum average transformed divergence between spectral classes (found by LARSYS Cluster Algorithm) of all possible pairs of blight levels, maximized over a subset of channels, was computed in each of one, two, three, and four spectral channels for each of ten flightlines. From the statistical analysis of the values of average transformed divergence, it was concluded that the greater the difference between the blight levels, the more statistically separable they are. This result is encouraging considering the fact that there are variables other than the blight severity within and between the flightlines. Although the analysis was done for corn blight only, the conclusions obtained from this analysis may well be applicable to other crop stresses because corn blight is representative of many plant stresses, especially non-systemic stresses.     

High stress abrasive wear behavior of sillimanite-reinforced Al-alloy matrix composite: A factorial design approach

An attempt has been made to explore the possibility of using a natural mineral, namely sillimanite, as dispersoid for synthesizing aluminum alloy composite by solidification technique. The abrasive wear behavior of this composite has been studied through factorial design of experiments. The wear behavior of the composite (Y _composite) and the alloy (Y _alloy) is expressed in terms of the coded values of different experimental parameters like applied load (x ₁), abrasive size (x ₂), and sliding distance (x ₃) by the following linear regression equations:

Flow injection analysis of an ultratrace amount of arsenite using a Prussian blue-modified screen-printed electrode

We report here a new electrochemical method for the selective detection of ultratrace amount of arsenite (AsO(2)(-), As(3+)) using a Prussian blue-modified screen-printed electrode (designated as PBSPE) by flow injection analysis (FIA) in 0.1 M, pH 4 KCl/HCl carrier solution. The Prussian yellow/Prussian blue redox couple of the PBSPE was found to mediate the As(3+) oxidation. Various factors influencing the determination of As(3+) were thoroughly investigated in this study. Under the optimized FIA conditions, a linear calibration plot in the range of 50 nM-300 microM with a detection limit (S/N = 3) of 25 nM (i.e., 64.9 pg in 20-microL loop) was observed at an operation potential of +0.6 V vs Ag/AgCl. The sensitivity was good enough to detect arsenite at levels lower than the current EPA standard. This modified electrode showed good resistance to interference from common ions, especially Cl(-), which is generally considered as a major interference in the determination of As(3+) by ICPMS. The practical utility of the PBSPE to detect As(3+) was demonstrated in "blackfoot" disease endemic village groundwater from the southwestern coast area of Taiwan (Pei-Men).     

Microtubule sensors and sensor array based on polyaniline synthesized in the presence of poly(styrene sulfonate)

Microtubule sensors for glucose, urea, and triglyceride were fabricated based on poly(styrene sulfonate)-polyaniline (PSS-PANI) composites synthesized within the pores of track-etched polycarbonate membranes. The synthesis of a sufficiently thick and conducting PSS-PANI film at pH 5 provided the advantage of immobilizing enzymes during polymerization. This resulted in the improvement of sensor response for urea and triglyceride by a factor of approximately 10(2) with a significant increase in the linear region of response compared to polyaniline-based sensors, where the enzymes were immobilized by physical adsorption after the polymerization. The sensors based on urea and triglyceride were found to have a higher linear range of response, better sensitivity, improved multiple use capability, and faster response time compared to the potentiometric and amperometric sensors based on polyaniline. A microtubule sensor array for glucose, urea, and triglyceride based on PSS-PANI was fabricated by immobilization of three different sets of enzymes on three closely spaced devices and its response was found to be free from cross-interference when a sample containing a mixture of the above analytes was analyzed in a single measurement.     

Performance Bounds of Algorithms for Scheduling Advertisements on a Web Page

Consider a set of n advertisements (hereafter called ads) A ={A₁,...,A_n} competing to be placed in a planning horizon which is divided into N time intervals called slots. An ad A _i is specified by its size s _i and frequency w _i. The size s _i represents the amount of space the ad occupies in a slot. Ad A _i is said to be scheduled if exactly w _i copies of A _i are placed in the slots subject to the restriction that a slot contains at most one copy of an ad. In this paper, we consider two problems. The MINSPACE problem minimizes the maximum fullness among all slots in a feasible schedule where the fullness of a slot is the sum of the sizes of ads assigned to the slot. For the MAXSPACE problem, in addition, we are given a common maximum fullness S for all slots. The total size of the ads placed in a slot cannot exceed S. The objective is to find a feasible schedule of ads such that the total occupied slot space is maximized. We examine the complexity status of both problems and provide heuristics with performance guarantees.     

New Linear Program Performance Bounds for Closed Queueing Networks

We develop new linear program performance bounds for closed reentrantqueueing networks based on an inequality relaxation of the averagecost equation. The approach exploits the fact that the transitionprobabilities under certain policies of closed queueing networksare invariant within certain regions of the state space. Thisinvariance suggests the use of a piecewise quadratic functionas a surrogate for the differential cost function. The linearprogramming throughput bounds obtained are provably tighter thanpreviously known bounds at the cost of increased computationalcomplexity. Functional throughput bounds parameterized by thefixed customer population N are obtained, alongwith a bound on the limiting throughput as N + .We show that one may obtain reduced complexity bounds while stillretaining superiority.     

Process control in CNC manufacturing for discrete components: A STEP-NC compliant framework

With today's highly competitive global manufacturing marketplace, the pressure for right-first-time manufacture has never been so high. New emerging data standards combined with machine data collection methods, such as in-process verification lead the way to a complete paradigm shift from the traditional manufacturing and inspection to intelligent networked process control. Low-level G and M codes offer very limited information on machine capabilities or work piece characteristics which consequently, results in no information being available on manufacturing processes, inspection plans and work piece attributes in terms of tolerances, etc. and design features to computer numerically controlled (CNC) machines. One solution to the aforementioned problems is using STEP-NC (ISO 14649) suite of standards, which aim to provide higher-level information for process control. In this paper, the authors provide a definition for process control in CNC manufacturing and identify the challenges in achieving process control in current CNC manufacturing scenario. The paper then introduces a STEP-compliant framework that makes use of self-learning algorithms that enable the manufacturing system to learn from previous data and results in eliminating the errors and consistently producing quality products. The framework relies on knowledge discovery methods such as data mining encapsulated in a process analyser to derive rules for corrective measures to control the manufacturing process. The design for the knowledge-based process analyser and the various process control mechanisms conclude the paper.     

A novel potentiometric membrane sensor for determination of Co based on 5-amino-3-methylisothiazole

A new poly(vinylchloride) (PVC) membrane electrode for trace level determination of Co²⁺ ions has been developed based on 5-amino-3-methylisothiazole as an ionophore, o-nitrophenyloctylether as a plasticizer and oleic acid (OA) as a good lipophilic additive. The electrode exhibits a Nernstian slope of 29.5 ± 0.2 mV/decade in a linear range of 1.0 × 10⁻¹ to 6.3 × 10⁻⁷ M for Co²⁺ ions. The detection limit of this electrode is 3.9 × 10⁻⁷ M. It has a fast response time of 12 s and can be used for a period of 4 months without any divergence in potentials. The proposed electrode reveals a good selectivity for Co (II) over a wide variety of other tested cations and could be used in the pH range 3.3–9.0. The electrode was successfully applied as an indicator electrode for the potentiometric titration of cobalt ions with EDTA as well as for the direct determination of Co (II) in real samples.     

A transaction model and multiversion concurrency control for mobile database systems

Transaction management on Mobile Database Systems (MDS) has to cope with a number of constraints such as limited bandwidth, low processing power, unreliable communication, and mobility etc. As a result of these constraints, traditional concurrency control mechanisms are unable to manage transactional activities to maintain availability. Innovative transaction execution schemes and concurrency control mechanisms are therefore required to exploit the full potential of MDS. In this paper, we report our investigation on a multi-versions transaction processing approach and a deadlock-free concurrency control mechanism based on multiversion two-phase locking scheme integrated with a timestamp approach. We study the behavior of the proposed model with a simulation study in a MDS environment. We have compared our schemes using a reference model to argue that such a performance comparison helps to show the superiority of our model over others. Experimental results demonstrate that our model provide significantly higher throughput by improving degree of concurrency, by reducing transaction wait time, and by minimizing restarts and aborts.