Improved Spectrum Mobility using Virtual Reservation in Collaborative Cognitive Radio Networks

Cognitive radio technology would enable a set of secondary users (SU) to opportunistically use the spectrum licensed to a primary user (PU). On the appearance of this PU on a specific frequency band, any SU occupying this band should free it for PUs. Typically, SUs may collaborate to reduce the impact of cognitive users on the primary network and to improve the performance of the SUs. In this paper, we propose and analyze the performance of virtual reservation in collaborative cognitive networks. Virtual reservation is a novel link maintenance strategy that aims to maximize the throughput of the cognitive network through full spectrum utilization. Our performance evaluation shows significant improvements not only in the SUs blocking and forced termination probabilities but also in the throughput of cognitive users.Comment: 7 pages, 10 figures, IEEE ISCC 201

Software-Engineering Process Simulation (SEPS) model

The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments

Perceptions of Disabilities and the Effect in the Design of Inclusive Environments

Individuals with a disability and/or impairment(s) have had a long history battling with acceptance in mainstream society, life as an individual with a disability has changed with time, for example; in the Babylon era births of children with congenial impairments were used to predict the future; in the Renaissance period in Europe physical beauty and perfection was revived, fast forward to today’s time the United Kingdom hosted the Paralympic Games in 2012. What is deemed as acceptable and our understanding of the term “disability” has come a long way, important milestones have sometimes been achieved by way of protests and petitions resulting in legislation being passed. Designing inclusive buildings and the environments surrounding them is largely directed by the designer’s education, subconscious thoughts and ideas. In recent times the UK government and design bodies have hoped to direct inclusive design by introducing new, and fortifying existing legislation in conjunction with the Department of Work and Pensions rectifying and training professionals in understanding disability and to learn key skills when designing inclusive spaces. A qualitative method has been used in the form of questionnaires distributed via social media inviting professionals of the architecture and construction industry to partake in the research. The aim of this research is to explore perceptions within the architecture and construction industry and whether it has an affect when designing inclusive environments. The questionnaires concluded that preconceptions of disabilities within the architecture and construction industry do exist and education plays a dominating factor in changing our thought process. Moving forward it is recommended to carry out further investigations to establish how the preconceptions have formed and to evaluate the Built Environment Professional Education Project (BEPE) and its integration in higher education

Brane worlds and dark matter

Two problems related to dark matter is considered in the context of a brane world model in which the confinement of gauge fields on the brane is achieved by invoking a confining potential. First, we show that the virial mass discrepancy can be addressed if the conserved geometrical term appearing in this model is considered as an energy momentum tensor of an unknown type of matter, the so-called X-matter whose equation of state is also obtained. Second, the galaxy rotation curves are explained by assuming an anisotropic energy momentum tensor for the X-matter.Comment: 13 pages, 1 figure, to appear in IJMP