Multi-utility tunnel (MUT) have received increasing attention as an alternative method for installing subsurface infrastructure the distribution of electricity, telecommunications, water, sewage and district heating. MUTs are described a potentially more sustainable technology than conventional open-cut excavation (OCE), especially if entire life cycle these cable pipe networks is taken into ac...

We investigate the uplink of a power-controlled multi-user distributed antenna system (DAS) with antennas deployed on a circle. Applying results from random matrix theory, we prove that for such a DAS, the per-user sum rate and the total transmit power both converge as user number and antenna number go to infinity with a constant ratio. The relationship between the asymptotic per-user sum rate ...

Unitary space-time modulation is known to be an efficient means to communicate over non-coherent Multiple Input Multiple Output (MIMO) channels. In this letter, differential unitary space-time coding and non-coherent space-time coding for the training based approach of Kim and Tarokh are addressed. For this approach, necessary and sufficient conditions for multi-group decodability are derived i...

Telepresence conferencing systems seek to create an environment that gives users (or user groups) that are not co-located a feeling of colocated presence through multimedia communication that includes at least audio and video signals of high fidelity. A number of techniques for handling audio and video streams are used to create this experience. When these techniques are not similar, interopera...

Existing research methods are largely intended to be conducted colocated and synchronously with a study population, but this approach is not feasible with remote or distributed populations. We describe a needs assessment study we conducted on Facebook. We report on our use of adapted versions of commonly used HCI research methods and lessons learned from this approach.

Just to sit in this dark place, and magic takes place on the wall. For a moment, we forgot apartheid, we forgot there was another world that wasn’t good; we sat there, and were carried away by the dream of these American movies. Actor John Kani to Peter Davis 1990, 23 On January 25, 1959, a short but rather glowing review appeared in The Golden City Post, one of South Africa’s most popular news...

Current Web search tools, such as browsers and search engine sites, are designed for a single user, working alone. However, users frequently need to collaborate on information-finding tasks; for example, students often work together in groups on homework assignments. To address this need, we have prototyped and evaluated several collaborative web search tools (S 3 , SearchTogether, and CoSearch...

This paper describes recent changes in the relationship between firms and nation states. Firms are typically linked to the nation in which they began and are considered to have fixed national identities. While firms have reallocated various activities around the world in response to value creation opportunities, they have largely retained their national identities and their headquarter activiti...