“SPOCU”: scaled polynomial constant unit activation function

We address the following problem: given a set of complex images or a large database, the numerical and computational complexity and quality of approximation for neural network may drastically differ from one activation function to another. A general novel methodology, scaled polynomial constant unit activation function “SPOCU,” is introduced and shown to work satisfactorily on a variety of problems. Moreover, we show that SPOCU can overcome already introduced activation functions with good properties, e.g., SELU and ReLU, on generic problems. In order to explain the good properties of SPOCU, we provide several theoretical and practical motivations, including tissue growth model and memristive cellular nonlinear networks. We also provide estimation strategy for SPOCU parameters and its relation to generation of random type of Sierpinski carpet, related to the [pppq] model. One of the attractive properties of SPOCU is its genuine normalization of the output of layers. We illustrate SPOCU methodology on cancer discrimination, including mammary and prostate cancer and data from Wisconsin Diagnostic Breast Cancer dataset. Moreover, we compared SPOCU with SELU and ReLU on large dataset MNIST, which justifies usefulness of SPOCU by its very good performance.

Percent Change as a Measure of Price Escalation in Water and Energy Utilities

We advance the idea of using percent billing changes as a simple measure of price escalation. This simple yet underused metric may help evaluate rate structure design in public utilities. We illustrate how price escalation may generate useful insight for utility managers by analyzing rate structures from water utilities in British Columbia, Canada. We observe that increasing block rates may send weaker relative price signals to users than a simple constant unit charge, and that low volume users tend to receive the strongest relative price signals. Measuring price escalation may also allow one to quantify the distortions generated by fixed charges. We conclude that analysts may find it useful to include measures of price escalation in their portfolio of metrics to evaluate rate structures in energy and water utilities.

Ordering Renewable Resources: Groundwater, Recycling, and Desalination

Optimal recycling of minerals can be thought of as an integral part of the theory of the mine. In this paper, we consider the role that wastewater recycling plays in the optimal extraction of groundwater, a renewable resource. We develop a two-sector dynamic optimization model to solve for the optimal trajectories of groundwater extraction and water recycling. For the case of spatially increasing recycling costs, recycled water serves as a supplemental resource in transition to the steady state. For constant unit recycling cost, recycled wastewater is eventually used as a sector-specific backstop for agricultural users, while desalination supplements household groundwater in the steady state. In both cases, recycling water increases welfare by shifting demand away from the aquifer, thus delaying implementation of costly desalination. The model provides guidance on when and how much to develop resource alternatives.

Ab intio Investigations of Lattice Parameters in ZnMgO Alloys

We perform density functional theory calculations to determine equilibrium lattice parameters of wurtzite Zn1-xMgxO alloys for Mg concentrations x ranging from 0 to 31.25 %. We use the local density approximation (LDA) as well as the generalized gradient approximation (GGA) for the exchange correlation functional. For the lattice constants a and c we find a deviation from Vegard's law and a constant unit cell volume independent of the Mg concentration.

Compressive Strength and Density of Fly-Ash Substituted Soil-Cement Concrete

Soil-cement concrete can be manufactured by mixing portland cement, water and on-site soil and has been studied by the authors. This study deals with compressive strength and density of soil-cement concrete where the portland cement was partially substituted with fly-ash. Saturated surface-dry condition of on-site soils has never been taken into account in the conventional mix design whereas experiments of determining the saturated surface-dry conditions were carried out with the help of the concept of effective water content to assure the quality and the designed strength. Effects of fly-ash on the strength and density of soil-cement concrete were studied by altering cement-fly-ash ratio, soil-sand ratio, binder-water ratio and age under a constant unit water content

The use of levelised cost in comparing supply and demand side options

This paper explores the use of levelised cost in planning for infrastructure networks. Levelised cost provides a useful measure comparing supply or conservation options on varying scales on an equivalent basis. Comparison is made to annualised cost, a metric often used as a means of comparing different supply side options. Urban water supply is used as the primary example, however levelised cost is equally applicable to other infrastructure networks, such as electricity or gas. The levelised cost is calculated as the ratio of the present value of projected capital and operating cost of an option to the present value of the projected annual demand supplied or saved by the option. The paper demonstrates that levelised cost is the constant unit cost of supply, provided by an option at present value. It is also the average incremental cost of the option at the point of implementation. When translated to a unit cost, annualised cost does not account for unutilised capacity in large scale schemes, systematically under-representing actual costs. By using levelised cost this inherent bias is removed. Use of levelised cost would facilitate the inclusion of smaller scale and more incremental supply options into infrastructure networks providing both economic and environmental benefits.

Design of Compliant Mechanical Amplifiers for Piezoceramic Stack Actuators Considering Stiffness Properties

A topology optimization method for design of compliant mechanical amplifiers for piezoceramic stack actuators is presented. Previously the optimization was done assuming that the stack actuator provided a constant unit load to the compliant mechanism. However, it is well known that the best actuator performance occurs when the stiffness of the stack is considered and matches the stiffness of the surrounding coupling structure. In this paper an improved formulation is presented where the piezoelectric properties and stiffness of the stack are included along with an external spring representing a resisting load the actuator is working against. The optimization problem formulation, finite element implementation, solution algorithm are discussed. Two design examples are presented which illustrate the effect of the stiffness of the external spring and the size of the design domain on the topology of the solution.

American and Soviet Medical Manpower: Growth and Evolution, 1910–1970

Between 1910 and 1970 the number of physicians in the United States increased 2.5 times, in Soviet Russia almost 25 times. The number of physicians per constant unit of population remained fairly stable in the United States, rising slightly in the last few years. In the U.S.S.R. that number increased 16 to 18 times, and now stands about 50 per cent higher than in the United States. About 10 per cent of American physicians are women; in the U.S.S.R. it is about 70 per cent. Neither society has resolved the problem of deploying physicians to the rural areas. American physicians are more specialized than their Soviet colleagues. The article concludes with general remarks about the two health systems, pointing out resemblances and divergences. The hypothesis of a possible “convergence” is entertained.