The aim of this paper is to study the Aloha medium access (MAC) scheme in one-dimensional, linear networks, which might be an appropriate assumption for Vehicular Ad-hoc NETworks (VANETs). We study performance metrics based on the signal-over-interference and noise ratio (SINR) assuming power-law mean path-loss and independent point-to-point fading. We derive closed formulas for the capture pro...

Ethernet is the most widely used network and many analytical models were developed to predict its capacity. Usually in these models assumptions like infinite population, no back-off algorithm and slotted channel are made. By comparing two models (one slotted and the other non-slotted) with reported measurements, we showed the optimistic estimate of the channel capacity of the slotted model is n...

The stability of slotted ALOHA systems with various types of capture phenomena and multiple packet reception capability is discussed in conjunction with the cusp catastrophe. The slotted ALOHA systems considered are classified into; 1) single packet reception with geometric capture, 2) independent multiple packet reception with geometric capture, 3) single packet reception with M -out-of-N capt...

A new multiple C-slotted microstrip patch antenna is proposed in the present study. A patch antenna is a wide-beam narrowband antenna. The microstrip patch antenna consists of a very thin metallic strip (patch) placed a small fraction of a wavelength above a ground plane. The patch can be designed in any possible shape and normally made of conducting materials such as copper or gold. This study...

Fama and French (1992) show conclusively that the relationship between cross-sectional stock return and beta is flat. Following Fama and French’s cross-sectional framework but allowing for up and down market conditions, Pettengill et al.’s (1995) constant-beta model and Howton and Peterson’s (1998) dual-beta model both find that beta is significantly positive (negative) in the up (down) markets...

In this study we investigate the performance of TCP and MAC layer in a wireless multi-hop network. Using simulation, we provide new insights into the interactions between TCP and various MAC layer protocols, including CSMA, FAMA and 802.11. These MAC protocols were chosen because they provide an evolution of wireless medium access schemes, starting with carrier sensing (CSMA), then evolving to ...

C often decry an earnings-focused short-term orientation of management that eschews spending on risky, long-term projects such as innovation to boost a firm’s stock price. Such critics assume that stock markets react positively to announcements of immediate earnings but negatively to announcements of investments in innovation that have an uncertain long-term pay off. Contrary to this position, ...

In this paper we present new empirical evidence on the agency based asset pricing model of Brennan (1993). We find strong evidence that in the recent period stocks whose returns covary more with the idiosyncratic component of the S&P500 return have significantly lower returns, holding constant either the market beta or the loadings on the Fama-French factors. The effect is confined mainly to la...

Asymmetric-circular shaped slotted microstrip patch antennas with slits are proposed for circularly polarized(CP) radiation and radio frequency identification reader applications. A single-feed configuration based asymmetric-circular shaped slotted square microstrip patches are adopted to realize the compact circularly polarized microstrip antenna. The CP radiation can be achieved by slightly a...