Prediction of Computer and Video Game Playing Population: An Age Structured Model

Models based on stage structure have found varied applications in population models. This paper proposes a stage structured model to study the trends in the computer and video game playing population of US. The game paying population is divided into three compartments based on their age group. After simulating the mathematical model, a forecast of the number of game players in each stage as well as an approximation of the average age of game players in future has been made.

14-Bit 1MS/s Cyclic-Pipelined ADC

This paper presents a 14-bit cyclic-pipelined Analog to digital converter (ADC) running at 1 MS/s. The architecture is based on a 1.5-bit per stage structure utilizing digital correction for each stage. The ADC consists of two 1.5-bit stages, one shift register delay line, and digital error correction logic. Inside each 1.5-bit stage, there is one gain-boosting op-amp and two comparators. The ADC was implemented in 0.18µm CMOS process and the design has an area of approximately 0.2 mm2. The ADC has a differential input range of 1.2 Vpp. The circuit has an average power consumption of 3.5mA with 10MHz sampling clocks. The post-layout simulations of the design satisfy 12-bit SNDR with a full-scale sinusoid input.

Stability and HOPF Bifurcation Analysis in a Stage-structured Predator-prey system with Two Time Delays

A stage-structured predator-prey system with two time delays is considered. By analyzing the corresponding characteristic equation, the local stability of a positive equilibrium is investigated and the existence of Hopf bifurcations is established. Formulae are derived to determine the direction of bifurcations and the stability of bifurcating periodic solutions by using the normal form theory and center manifold theorem. Numerical simulations are carried out to illustrate the theoretical results. Based on the global Hopf bifurcation theorem for general functional differential equations, the global existence of periodic solutions is established.

Hopf Bifurcation Analysis for a Delayed Predator–prey System with Stage Structure

In this paper, a delayed predator–prey system with stage structure is investigated. Sufficient conditions for the system to have multiple periodic solutions are obtained when the delay is sufficiently large by applying Bendixson-s criterion. Further, some numerical examples are given.