In wireless local area networks (WLAN) based on IEEE 802.11, when the number of wireless terminals connecting to the same access point (AP) increases, data frame collisions cause the decreasing of total throughput for all wireless terminals. To address this problem, we have proposed a new media access control (MAC) method, Synchronized Phase MAC (SP-MAC), based on the synchronization phenomena ...

A new approach to the discretionary access control in structurally object-oriented databases is suggested. The approach is based on the use of pseudo-random functions and sibling intractable functions, rather than on the traditional access control list associated with each class. The advantage of this approach is that each class in the hierarchy of a complex object class can be associated with ...

Insider attacks are among the most dangerous and costly attacks to organizations. These attacks are carried out by individuals who are legitimately authorized to access the system. Preventing insider attacks is a daunting task. The recent proliferation of social media and mobile devices offer new opportunities to collect geo-social information that can help in detecting and deterring insider at...

This thesis examines the challenge of robust audio-visual person verification using data recorded in multiple environments with various lighting conditions, irregular visual backgrounds, and diverse background noise. Audio-visual person verification could prove to be very useful in both physical and logical access control security applications, but only if it can perform well in a variety of en...

This paper proposes a new media access protocol for single-hop local area and metropolitan area all-optical networks employing wavelength division multiplexing (WDM). Through WDM, multiple channels are created on a single ber, and an aggregate network bandwidth far greater than the peak electronic processing speed can be realized. The new protocol, Dynamic Media Access Control Scheme (DMACS), i...

Internalization of a thin ideal has been posited as a key risk factor in the development of pathological eating attitudes. Cross-culturally, studies have found a preference for heavier bodies in populations with reduced access to visual media compared to Western populations. As yet, however, there has been little attempt to control for confounding variables in order to isolate the effects of me...

The ability to control access to sensitive data in accordance with policy is perhaps the most fundamental security requirement. Despite over four decades of security research, the limited ability for existing access control mechanisms to generically enforce policy persists. While researchers, practitioners and policy makers have specified a large variety of access control policies to address re...

There is considerable interest within the Human Computer Interaction (HCI) community in the use of media spaces to enhance awareness and interaction between workers in ooces or other spatially distributed environments. In addition to the technical challenges of providing reliable and eecient audiovisual communication, there are important social questions, in particular how users are able to con...