An enhanced relay-enabled medium access control protocol for wireless ad hoc networks

In this paper we propose an enhanced relay-enabled distributed coordination function (rDCF) for wireless ad hoc networks. The idea of rDCF is to use high data rate nodes to work as relays for the low data rate nodes. The relay helps to increase the throughput and lower overall blocking time of nodes due to faster dual-hop transmission. rDCF achieves higher throughput over IEEE 802.11 distributed coordination function (DCF). The protocol is further enhanced for higher throughput and reduced energy. These enhancements result from the use of a dynamic preamble (i.e. using short preamble for the relay transmission) and also by reducing unnecessary overhearing (by other nodes not involved in transmission). We have modeled the energy consumption of rDCF, showing that rDCF provides an energy efficiency of 21.7% at 50 nodes over 802.11 DCF. Compared with the existing rDCF, the enhanced rDCF (ErDCF) scheme proposed in this paper yields a throughput improvement of 16.54% (at the packet length of 1000 bytes) and an energy saving of 53% at 50 nodes.

How can a blind engineer access the curriculum?

The arrival of a student who is Blind in the School of Systems Engineering at the University of Reading has made it an interesting and challenging year for all. Visually impaired students have already graduated from other Schools of the University and the School of Systems Engineering has seen three students with visual impairment graduate recently with good degrees. These students could access materials - and do assessments - essentially by means of enlargement and judicious choice of options. The new student had previously been supported by a specialist college. She is a proficient typist and also a user of both Braille and JAWS screen reader, and she is doing a joint course in Cybernetics and Computer Science. The course requires mathematics which itself includes graphs, and also many diagrams including numerous circuit diagrams. The University bought proven equipment such as a scanner to process books into speech or Braille, and screen reading software as well as a specialist machine for producing tactile diagrams for educational use. Clearly it is also important that the student can access assessments and examinations and present answers for marking or feedback (by sighted staff). So the School also used innovative in-house tactile methods to represent diagrams. This paper discusses the success or otherwise of various modifications of course delivery and the way forward for the next three years.

KAIFIA: Knowledge assisted intelligent framework for information access

Accessing information, which is spread across multiple sources, in a structured and connected way, is a general problem for enterprises. A unified structure for knowledge representation is urgently needed to enable integration of heterogeneous information resources. Topic Maps seem to be a solution for this problem. The Topic Map technology enables connecting information, through concepts and relationships, and their occurrences across multiple systems. In this paper, we address this problem by describing a framework built on topic maps, to support the current need of knowledge management. New approaches for information integration, intelligent search and topic map exploration are introduced within this framework.

Generating virtual environments to allow increased access to the built environment

The problems encountered by individuals with disabilities when accessing large public buildings is described and a solution based on the generation of virtual models of the built environment is proposed. These models are superimposed on a control network infrastructure, currently utilised in intelligent building applications such as lighting, heating and access control. The use of control network architectures facilitates the creation of distributed models that closely mirror both the physical and control properties of the environment. The model of the environment is kept local to the installation which allows the virtual representation of a large building to be decomposed into an interconnecting series of smaller models. This paper describes two methods of interacting with the virtual model, firstly a two dimensional aural representation that can be used as the basis of a portable navigational device. Secondly an augmented reality called DAMOCLES that overlays additional information on a user’s normal field of view. The provision of virtual environments offers new possibilities in the man-machine interface so that intuitive access to network based services and control functions can be given to a user.

Community mix, affordable housing and metropolitan planning strategy in Melbourne

Income segregation across Melbourne’s residential communities is widening, and at a pace faster than in some other Australian cities. The widening gap between Melbourne’s rich and poor communities raises fears about concentrations of poverty and social exclusion, particularly if the geography of these communities is such that they and their residents are increasingly isolated from urban services and employment centres. Social exclusion in our metropolitan areas and the government responses to it are commonly thought to be the proper domain of social and economic policy. The role of urban planning is typically neglected, yet it helps shape the economic opportunities available to communities in its attempts to influence the geographical location of urban services, infrastructure and jobs. Under the current metropolitan strategy ‘Melbourne 2030’ urban services and transport infrastructure are to be concentrated within Principal Activity Centres spread throughout the metropolitan area and it is the intention that lower-income households should have ready access to these activity centres. However, the Victorian state government has few housing policy instruments to achieve this goal and there are fears that community mix may suffer as house prices and rents are bid up in the vicinity of Principal Activity Centres, and lower-income households are displaced. But are these fears justified by the changing geography of house prices in the metropolitan region? This is the key research question addressed in this paper which examines whether the Victorian practice of placing reliance on the market to deliver affordable housing, while intervening to promote a more compact pattern of urban settlement, is effective.

Negotiating access into firms: obstacles and strategies

Researchers often experience difficulties with the negotiation of access into firms for the purpose of data collection. The question we explore is: What are the main obstacles associated with access negotiation into firms; and what strategies do researchers employ to increase their chances of success? Our research work on the tendering process of contractors took place between 2006 and 2008. We successfully negotiated access into four firms (two each in Ghana and the UK) to observe live examples of tender preparation The techniques we employed in negotiating access were personal contacts, contacting firms through online details and professional institutions, etc. With all of this effort, our average success rate was less than 5 per cent. The main obstacles encountered were firms’ reluctance because of commercial sensitiveness and fear that the data could eventually be divulged to their competitors or end up in the public domain. However, some firms agreed mainly because of the written assurances of confidentiality and anonymity in reporting the study; reputation of the researchers’ academic institution; gatekeepers who spoke to their colleagues on our behalf; academic purpose of the study; and a feedback report which was promised in return for access to the case studies. Although the access through personal contacts is by far the easiest, it is not always possible. Researchers can approach firms as complete strangers, especially in a foreign country, and that could make the firms more likely to assist the research.