land- phone, like mobile, internet and fax is a communication device and has network externality effect. thus as the penetration coefficient increases, the network effect improves. the transmission of information via the word of mouth is the main source of enhancing the network externalities coefficient. in this article we have investigated the factors affecting the network externality coeffici...

BACKGROUND The debate regarding the health effects of low-intensity electromagnetic radiation from sources such as power lines, base stations, and cell phones has recently been reignited. In the present review, the authors attempt to address the following question: is there epidemiologic evidence for an association between long-term cell phone usage and the risk of developing a brain tumor? Inc...

abstract background & aim: recent increase of hormonal disorders in human may be correlated to the increased exposure to electromagnetic fields produced by various instruments, including cell phones. thyroid gland is one of the organs most likely to be exposed to cell phone radiation. whereas garlic is known as reducing risk factors for various diseases. the aim of this study is to assess the a...

Use of cell phones has grown dramatically. By the turn of this century, cell phone use had reached a majority of the populations in Canada, the United States, Australia, Germany, Singapore, the United Kingdom, and Italy. However, a digital divide exists between people with and without disabilities in their use of mobile phones. Gaps in usage occur across all age groups. In a study by Bryen, Car...

With the advent of wireless communication and internet protocol, many technologies have been developed to provide mobile phone user with the wireless internet service. Security supporting wireless internet must be guaranteed at same level as the wired security. But PKI (Public Key Infrastructure) which is used for the security of e-commerce in wired internet is not suitable for the mobile phone...