Domination of sample maxima and related extremal dependence measures

For a given d-dimensional distribution function (df) H we introduce the class of dependence measures μ(H, Q) = −E{n H(Z1, . . . , Zd)}, where the random vector (Z1, . . . , Zd) has df Q which has the same marginal dfs as H. If both H and Q are max-stable dfs, we show that for a df F in the max-domain of attraction of H, this dependence measure explains the extremal dependence exhibited by F. Moreover, we prove that μ(H, Q) is the limit of the probability that the maxima of a random sample from F is marginally dominated by some random vector with df in the max-domain of attraction of Q. We show a similar result for the complete domination of the sample maxima which leads to another measure of dependence denoted by λ(Q, H). In the literature λ(H, H), with H a max-stable df, has been studied in the context of records, multiple maxima, concomitants of order statistics and concurrence probabilities. It turns out that both μ(H, Q) and λ(Q, H) are closely related. If H is max-stable we derive useful representations for both μ(H, Q) and λ(Q, H). Our applications include equivalent conditions for H to be a product df and F to have asymptotically independent components.

REDUCING STRUCTURAL ERROR IN FUNCTION GENERATING MECHANISMS VIA THE ADDITION OF LARGE NUMBERS OF FOUR-BAR MECHANISMS

This paper presents a methodology for synthesizing planarlinkages to approximate any prescribed periodic function. Themechanisms selected for this task are the slider-crank and thegeared five-bar with connecting rod and sliding output (GFBS),where any number of drag-link (or double crank) four-bars areused as drivers. A slider-crank mechanism, when comparing theinput crank rotation to the output slider displacement, producesa sinusoid-like function. Instead of directly driving the inputcrank, a drag-link four-bar may be added that drives the crankfrom its output via a rigid connection between the two. Drivingthe input of the added four-bar results in a function that is lesssinusoid-like. This process can be continued through the additionof more drag-link mechanisms to the device, slowly alteringthe curve toward any periodic function with a single maximum.For periodic functions with multiple maxima, a GFBS is usedas the terminal linkage added to the chain of drag-link mechanisms.The synthesis process starts by analyzing one period ofthe function to design either the terminal slider-crank or terminalGFBS. A randomized local search is then conducted as thefour-bars are added to minimize the structural error between thedesired function and the input-output function of the mechanism.Mechanisms have been “grown” in this fashion to dozens of linksthat are capable of closely producing functions with a variety ofintriguing features.

The Synthesis of Function Generating Mechanisms for Periodic Curves Using Large Numbers of Double-Crank Linkages

This paper presents a methodology for synthesizing planar linkages to approximate anyprescribed periodic function. The mechanisms selected for this task are the slider-crankand the geared five-bar with connecting rod and sliding output (GFBS), where any numberof double-crank (or drag-link) four-bars are used as drivers. A slider-crank mechanism,when comparing the input crank rotation to the output slider displacement,produces a sinusoid-like function. Instead of directly driving the input crank, a drag-linkfour-bar may be added to drive the crank from its output via a rigid connection betweenthe two. Driving the input of the added four-bar results in a function that modifies thesinusoid-like curve. This process can be continued through the addition of moredrag-link mechanisms to the device, progressively altering the curve toward any periodicfunction with a single maximum. For periodic functions with multiple maxima, a GFBS isused as the terminal linkage added to the chain of drag-link mechanisms. The synthesisprocess starts by analyzing one period of the function to design either the terminal slidercrankor terminal GFBS. MATLAB’s fmincon command is then utilized as the four-bars areadded to reduce the structural error between the desired function and the input–outputfunction of the mechanism. Mechanisms have been synthesized in this fashion to includea large number of links that are capable of closely producing functions with a variety ofintriguing features

The Synthesis of Function Generating Mechanisms for Periodic Curves Using Large Numbers of Double-Crank Linkages

This paper presents a methodology for synthesizing planar linkages to approximate any prescribed periodic function. The mechanisms selected for this task are the slider-crank and the geared five-bar with connecting rod and sliding output (GFBS), where any number of double-crank (or drag-link) four-bars are used as drivers. A slider-crank mechanism, when comparing the input crank rotation to the output slider displacement, produces a sinusoid-like function. Instead of directly driving the input crank, a drag-link four-bar may be added to drive the crank from its output via a rigid connection between the two. Driving the input of the added four-bar results in a function that modifies the sinusoid-like curve. This process can be continued through the addition of more drag-link mechanisms to the device, progressively altering the curve toward any periodic function with a single maximum. For periodic functions with multiple maxima, a GFBS is used as the terminal linkage added to the chain of drag-link mechanisms. The synthesis process starts by analyzing one period of the function to design either the terminal slider-crank or terminal GFBS. matlab's fmincon command is then utilized as the four-bars are added to reduce the structural error between the desired function and the input–output function of the mechanism. Mechanisms have been synthesized in this fashion to include a large number of links that are capable of closely producing functions with a variety of intriguing features.

Fluctuation enhancement of ion diffusivity in liquids

The diffusivity of ions in liquid solutions is known either to decrease with an increase in the ion size or to have a single maximum depending on the ion size. This article presents evidence for the appearance of multiple maxima and thus multiple ion sizes with enhanced diffusivity.

Reducing Structural Error in Function Generating Mechanisms via the Addition of Large Numbers of Four-Bar Mechanisms

This paper presents a methodology for synthesizing planar linkages to approximate any prescribed periodic function. The mechanisms selected for this task are the slider-crank and the geared five-bar with connecting rod and sliding output (GFBS), where any number of drag-link (or double crank) four-bars are used as drivers. A slider-crank mechanism, when comparing the input crank rotation to the output slider displacement, produces a sinusoid-like function. Instead of directly driving the input crank, a drag-link four-bar may be added that drives the crank from its output via a rigid connection between the two. Driving the input of the added four-bar results in a function that is less sinusoid-like. This process can be continued through the addition of more drag-link mechanisms to the device, slowly altering the curve toward any periodic function with a single maximum. For periodic functions with multiple maxima, a GFBS is used as the terminal linkage added to the chain of drag-link mechanisms. The synthesis process starts by analyzing one period of the function to design either the terminal slider-crank or terminal GFBS. A randomized local search is then conducted as the four-bars are added to minimize the structural error between the desired function and the input-output function of the mechanism. Mechanisms have been “grown” in this fashion to dozens of links that are capable of closely producing functions with a variety of intriguing features.