A decision support system for locating weapon and radar positions in stationary point air defence

In this study, a decision support system (DSS) based on the interactive use of location models and geographical information systems (GIS) was developed to determine the optimal positions for air defence weapons and radars. In the location model, the fire units are considered as the facilities to be located and the possible approach routes of air vehicles are treated as demand points. Considering the probability that fire by the units will miss the targets, the objective of the problem is to determine the positions that provide coverage of the approach routes of the maximum number of weapons while considering the military principles regarding the tactical use and deployment of units. In comparison with the conventional method, the proposed methodology presents a more reliable, faster, and more efficient solution. On the other hand, owing to the DSS, a battery commander who is responsible for air defence becomes capable of determining the optimal weapon and radar positions, among the alternative ones he has identified, that cover the possible approach routes maximally. Additionally, he attains the capability of making such decisions in a very short time without going to the field over which he will perform the defence and hence without being subject to enemy threats. In the decision support system, the digital elevation model is analysed using Map Objects 2.0, the mathematical model is solved using LINGO 4.0 optimization software, and the user interface and data transfer are supported by Visual Basic 6.0.     

Simulation of throughput from remote batch entry terminals

Operation of the remote batch terminals connected to an IBM 370/158 computer system at a large mid-western firm is simulated using GPSS language. The performance of the computer system was simulated to determine the impact of changes to be imposed on the system. The model parameters of remote printer speed and core storage capacity were altered during the course of the simulation. These variables were selected for their flexibility in relationship to the total network and the relative ease of implementing such changes. It is found that implementing higher speed printers and increased computer core storage capacity can decrease printer and core storage utilizations and the average service rate drastically.     

Suprathreshold intrinsic dynamics of the human visual system

Intrinsic high-frequency neural activities have been observed in the visual system of several species, but their functional significance for visual perception remains a fundamental puzzle in cognitive neuroscience. Spatiotemporal integration in the human visual system acts as a low-pass filter and makes the psychophysical observation of high-frequency activities very difficult. A computational model of retino-cortical dynamics (RECOD) is used to derive experimental paradigms that allow psychophysical studies of high-frequency neural activities. A reduced-parameter version of the model is used to quantitatively relate psychophysical data collected in two of these experimental paradigms. Statistical analysis shows that the model's account of the variance in the data is, in general, highly significant. We suggest that psychophysically measured oscillations reflect intrinsic neuronal oscillations observed in the visual cortex.     

Price and capacity competition of application services duopoly

In this paper, we study the price and capacity competition of two application service providers (ASPs). The customers realize an intrinsic time-independent value from transactions processed by the ASP. The cost to the customers includes both the price charged by the ASP and the delay cost due to turnaround time of the ASP service system. Customers will choose to join the ASP who delivers a higher net value of the service. This paper examines the competition between two ASPs and the impact of customers' delay cost on ASP's pricing and capacity decisions. We find that the ASP with higher capacity will charge a higher price and enjoy a larger market share and, surprisingly, that customers' delay cost has no direct impact on the arrival rates to the ASPs but affects the ASPs' pricing decisions. The ASPs will charge a higher price premium to capitalize customers' higher delay cost. For the long-run problem, we find that in the presence of higher customer's delay cost, both ASPs' optimal profits suffer, in contrast to the short-run problem where a higher customer's delay cost leads to a higher profitability for both ASPs.     

High-Temperature Oxidation of Boron Nitride: I, Monolithic Boron Nitride

High-temperature oxidation of monolithic boron nitride (BN) is examined at 900–1200°C. Hot-pressed BN and both low- and high-density chemically vapor-deposited BN are studied. The oxidation product is B₂O₃( l ) and the oxidation kinetics are sensitive to crystallographic orientation, porosity, and impurity levels. The B₂O₃ product also reacts readily with ambient water vapor in the test furnace (ppm levels) to form the volatile species HBO₂( g ), leading to overall paralinear kinetics. The linear rate constant extracted from these experiments agreed with that predicted from diffusion of HBO₂( g ) across a static boundary layer.     

Spectrophotometric and electrochemical behavior of a novel azocalix[4]arene derivative as a highly selective chromogenic chemosensor for Cr

In this study, a novel azocalix[4]arene derivative, 5,11,17-tris[(1-naphtyl)azo]-25,26,27,28-tetrahydroxy-calix[4]arene (NAC4) bearing napthyl groups on the upper rim was synthesized. Its complexation behavior for alkali, alkaline-earth and various heavy metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Hg²⁺, Ni²⁺, Cd²⁺, Cu²⁺, Zn²⁺, Co²⁺, Fe²⁺, Cr³⁺, Ag⁺) was investigated by spectroscopic and voltammetric methods. This chemosensor exhibits decreased absorbance in the presence of Hg²⁺ and a unique absorbance quenching effect only for Cr³⁺. In addition, a new absorption band centered at 565 nm with the formation of the 1:1 host–guest complex (Cr³⁺-NAC4) was observed in the case of Cr³⁺, leading to an obvious color change from light orange to dark lilac. In voltammetric experiments, Cr³⁺ ions decreased voltammetric peaks of NAC4, whereas no significant changes occurred in the presence of the other metal ions. The Benesi–Hildebrand method was used to determine a logarithmic value of 3.76 for the association constant of the complex between Cr³⁺ and NAC4.     

Characterizing temporal development of biofilm porosity using artificial neural networks

We used artificial neural networks (ANN) to compute parameters characterising biofilm structure from biofilm images and to interpolate a limited number of experimental data characterising the effects of nutrient concentration and flow velocity on the areal porosity of biofilms. ANN were trained using a set of experimental data characterising structural parameters of biofilms of Pseudomonas aeruginosa (ATCC #700829), Pseudomonas fluorescens (ATCC #700830) and Klebsiella pneumoniae (ATCC #700831) for various flow velocities and glucose concentrations. We used 80% of the data to train ANN and 10% of the data to validate the results, which is routinely carried out as a countermeasure against overtraining. Trained ANN were used to interpolate into the data set and evaluate the missing 10% of the data. To compare ANN accuracy in evaluating the missing data with the accuracies achieved using other interpolation algorithms, we used spline, cubic, linear and nearest-neighbour interpolation algorithms to evaluate the missing data. ANN estimates were consistently closer to the experimental data than the estimates made using the other methods.     

Solid-liquid reactions: The effect of Cu content on Sn-Ag-Cu interconnects

The impact of copper content on the Sn-Ag-y%Cu (Ag=constant=3.5; y=0.0, 0.5, 1.0, and 2.0) interconnects was investigated in this study. The copper content and solid-liquid (S-L) reactions were used as inputs, and the outputs were the interfacial microstructure evolution and joint macro-performance. Surface microetching microscopy, cross-section microscopy, energy-dispersive x-ray analysis, shear test, and differential scanning calorimetry were used in the studies. It was discovered that as-soldered Sn-Ag-y%Cu interconnects could have different interfacial microstructures depending on copper content; no Ag₃Sn plates were observed for any alloy groups. After the S-L reactions, Ag₃Sn plates occurred for all groups. The magnitude of the Ag₃Sn plate growth depended on copper content. This and other effects of copper content on Sn-Ag-Cu interconnects are discussed in this article.     

New perylene derivative dyes for dye-sensitized solar cells

We have studied the influence of the spacer alkyl chain length of perylenemonoimide (PMI) dyes on the device performance in dye-sensitized solar cells (DSSCs). We observed that the dyes with longer and brunched alkyl chains exhibit higher efficiencies in DSSCs. In line with these statements we now report the highest efficiency obtained under standard conditions for a perylene imide derivative with PMI-DA1 that performs 300 mV open circuit voltage, 9.79 mA/cm² short-circuit current and 1.61% overall conversion efficiency.     

The optimum die profile for the cylindrical bending of plates

This paper presents a methodology for the design of plate-forming dies in cylindrical bending using optimization techniques to reduce the cost of die production by reducing the trial-and-error procedure considerably in determining the final die geometry. The plate thickness is discretized by plane-strain finite-elements. The die is taken to be rigid and its profile is approximated by Bezier curves the control-point coordinates of which are the design variables. The die profile is varied to minimize the difference between the required shape and the shape of the bent plate, considering springback action. The unconstrained optimization problem is solved by the BFGS (Broyden-Fletcher-Goldfarb-Shanno) method. A numerical example is presented where the optimum die profile is obtained for a plate bent into a quarter circle.