The Systems Modeling Language (SysML) is a general-purpose, graphical modeling language for product and systems development. The new standard gives systems engineers and architects a much-needed way to collaborate using a common language specifically designed for systems engineering. This month, we introduce SysML by presenting a real-life example of a product with multiple sub-systems, all of ...

Suppose a, b, c, and d are rational numbers such that a2, b2, c2, and d2 form an arithmetic progression: the differences b2−a2, c2−b2, and d2−c2 are equal. One possibility is that the arithmetic progression is constant: a2, a2, a2, a2. Are there arithmetic progressions of four rational squares which are not constant? This question was first raised by Fermat in 1640. There are no such progressio...

A population of fully rational agents play a symmetric 2-player game in biological fitnesses, but each agent’s play is determined by his payoffs, which are free to evolve according to “survival of the fittest” pressures. An equilibrium-selection mechanism is assumed to exist, and deliver a unique outcome for any given profile of payoffs; this allows the evolution of payoffs to be modeled as a w...

The world we live in contains animate and inanimate objects, and adults think about these classes of objects in different ways. Consider one clear case from each class: a cat and a chair. We expect a young kitten to grow an4 change shape over time, but do not expect a newly made chair to do this. If one used instruments to alter the shape of the chair, we might not accept the result as the same...

in this paper we investigate the behavior of solutions, stable and unstable of the solutions a second-order rational difference equation. also we will discuss about the behavior of solutions a the rational system, we show these solutions may be stable or unstable.

In this chapter, we conduct a comparative study of various traders following different trading strategies. We design an agent-based artificial stock market consisting of two opposing types of traders: “rational traders” (or “fundamentalists”) and “imitators” (or “chartists”). Rational traders trade by trying to optimize their short-term income. On the other hand, imitators trade by copying the ...

Current employment strategies usually rely on some rational compromise between hiring people with skills that are needed immediately and hiring people with skills that will likely be needed in the future. A more open approach to innovation promises access to “smart people” that are outside of your organization. But most strategies fall far short of effectively tapping that external crowd. A new...

We prove a new result on N-rational series in one variable. This result gives, under an appropriate hypothesis, a necessary and suucient condition for an N-rational series to be of star-height 1. The proof uses a theorem of Handelman on integral companion matrices.