Barry Dwolatzky

Linking the global positioning system (GPS) to a personal digital assistant (PDA) to support tuberculosis control in South Africa: a pilot study.

BackgroundTuberculosis (TB) is the leading clinical manifestation of HIV infection and caseloads continue to increase in high HIV prevalence settings. TB treatment is prolonged and treatment interruption has serious individual and public health consequences. We assessed the feasibility of using a handheld computing device programmed with customised software and linked to a GPS receiver, to assist TB control programmes to trace patients who interrupt treatment in areas without useful street maps. In this proof of concept study, we compared the time taken to re-find a home comparing given residential addresses with a customised personalised digital assistant linked to a global positioning system (PDA/GPS) device. Additionally, we assessed the feasibility of using aerial photographs to locate homes.ResultsThe study took place in two communities in Greater Johannesburg, South Africa: Wheillers Farm, a relatively sparsely populated informal settlement, and a portion of Alexandra, an urban township with densely populated informal settlements. Ten participants in each community were asked to locate their homes on aerial photographs. Nine from Wheillers Farm and six from Alexandra were able to identify their homes. The total time taken by a research assistant, unfamiliar with the area, to locate 10 homes in each community using the given addresses was compared with the total time taken by a community volunteer with half an hour of training to locate the same homes using the device. Time taken to locate the ten households was reduced by 20% and 50% in each community respectively using the PDA/GPS device.ConclusionIn this pilot study we show that it is feasible to use a simple PDA/GPS device to locate the homes of patients. We found that in densely populated informal settlements, GPS technology is more accurate than aerial photos in identifying homes and more efficient than addresses provided by participants. Research assessing issues of, confidentiality and cost effectiveness would have to be undertaken before implementing PDA/GPS – based technology for this application. However, this PDA/GPS device could be used to reduce part of the burden on TB control programs.

Demand-side energy management performed using direct feedback via mobile systems: Enables utilities to deploy consumer based demand response programs

Electricity demand in developing countries is expected to rise significantly by the year 2020. Electricity consumers in both developed and developing countries are not active participants in the operations of electrical networks. Research has shown that significant benefits may be achieved when consumers participate in such electrical network operations. In these instances consumers were able to reduce their electrical energy consumption via coordinated demand response programs. However, there are some challenges in offering or deploying a consumer-based demand response program. This paper presents a novel system which enables electrical utilities to provide their consumers with a consumer-based demand response program.

Designing a usable mobile application for field data collection

It is envisaged that, particularly in African countries under the NEPAD initiative, mobile technology will play a crucial rote in the collection and maintenance of spatial information about the countrys infrastructure (i.e. water, electricity, roads, communication networks etc). While much of the underlying technology may already be available, usability of the mobile applications remains a serious concern. This work investigates the usability of a mobile application for field data collection in the utility industry. The purpose of the investigation is to gain better understanding of usability requirements for a mobile field data collection application but more importantly, how to meet these requirements from a usability engineering standpoint. Firstly, we give some background information on mobile computing and its role in field data collection. Secondly, we describe the design and implementation of the field data collection prototype. The analysis of usability requirements is based on a field study of underground utility closure sourcing work employed at a telecommunications utility. A usage-centered design approach is used to design the user interface, which is implemented as a working prototype on a pocket computer. And finally, we discuss the usability testing of the prototype.

Smart demand-side energy management based on cellular technology - a way towards Smart Grid technologies in africa and low budget economies

The century-old power grids were not designed to meet modern requirements. The current need to use electricity more efficiently and to introduce “green” sources of energy is not well supported by existing grid technology. A particular problem is that detailed information about consumption of electricity is not provided to users and network operators. This is one of the prime reasons for electricity wastage. The “Smart Grid” concept is a solution to this problem. Smart Grid solutions at this moment in time are expensive to deploy. For developing countries it is particularly difficult to benefit from Smart Grid solutions. This paper proposes a system that can be used in developing economies as a way of reducing the consumption and wastage of electricity. The solution uses cell phones as an instrument to both display information and allow consumers to control appliances in their homes. This will be integrated into a larger Smart Grid application. The paper presents a concept that is still to be implemented and tested.

Radar simulation using the shooting and bouncing ray technique

This paper is based on the design and development of an electromagnetic simulation package used for predicting the radar cross section (RCS) of partially open cavities. In the RCS analysis of objects such as aircrafts or ships, the cavity structures (such as air-vents and jet outlets) play a major role to the contribution of the reflected radar. Thus cavities can be seen as having a certain stealthiness-coefficient to them. By manipulating their physical shape one can reduce the amount of RCS backscatter reflected. The simulation process applies the shooting-and-bouncing-ray (SBR) method in conjunction with electromagnetic field theory. A vector effective height (VEH), of the antenna used, is introduced to take into account the polarization coupling effects resulting from each reflection within the cavity. The final gain of the power received can be determined by the incoherent summation of all the contributing rays. To verify the validity of the simulation, a comparison is made to the RCS scan of a rectangular cavity. The results show a close correlation between the simulated and measured environments. Furthermore, an illustration of RCS optimization is shown by modifying the rectangular cavities dimensions and comparing the two results.

A review of the widget landscape and incompatibilities between widget engines

A widget is a packaged interactive client-side application, commonly developed using Web standards and techniques to access data services both on theWeb and host devices. The purpose of this paper is to review the widget landscape and present key characteristics and concerns of widget technologies. Various incompatibilities exist between widgets and the proprietary engines hosting them on different platforms. Incompatibilities can be classified by how different implementations handle issues related to packaging, behaviour, security and presentation. These common concerns, together with economic drivers have given rise to numerous standardisation efforts such as those being carried out by the W3C in drafting the widget family of specifications.

Balancing the human and the engineering factors in software development

This work analyses the effect of putting more weight on the human factor to the overall control and management of the software development process. We are going to use a case study of one software development company in South Africa that is working on a large nontrivial database system and is not following any laid down methodology. Our analysis revealed that the companys way of developing software is closely aligned to the Agile methodology principles. From this case study it is clear that there is need for a balance between the human factor and the engineering factor in order to avoid possible problems such as poor technical documentation.

An empirical investigation of the accuracy of location-based services in South Africa

This article describes an empirical investigation of factors influencing the accuracy of location-based services (LBS) on GSM phones in South Africa. The experimental settings were three distinct environments in Johannesburg, South Africa. The results indicated that some parameters such as geographical location and environment of an LBS request have a significantly high impact on the accuracy of LBS. In addition, there was also a huge difference between the predicted and provided accuracies by mobile location providers. This article concludes with a discussion of solutions on bridging the gap between the predicted and provided accuracies to LBS users with the view of improving LBS user dependability on the service provided.

Linear Slip Control Formulation for Vehicular Anti-Lock Braking System with Suspension Effects

Abstract This paper presents the formulation of a slip-control model for purposes of performing slip tracking of target slip. System modeling is performed to develop a braking model incorporating an active suspension. Linearisation of the highly non-linear multi-input multi-output developed Anti-lock Braking System model is performed by way of input-output feedback linearisation. Feedback linearisation is shown to provide a transformed linear ABS model while ensuring a verifiable stable state transformation. Lie algebra is used to find the stability of the internal dynamics through zero dynamics analysis. Simulation results demonstrate the validity of the approach along with the development of a stabilising condition for the linearisation approach.

Conceptual framework that supports environment-aware positioning and improved QOS for Location Based Services

Location Based Services (LBS) enables mobile users to have access to information based on their current geographical location. LBS are an important aspect of the ubiquitous wireless world and are paving the way to provide users with customizable services anywhere and at anytime. It is worth noting that there are different accuracy requirements for different LBS and not all location methods can provide the required accuracy due to error sources. Mobile network operators need to know which location method is best suited for the required accuracy of LBS based on the dynamically varying factors that affects the location method. The sources of the errors include geographical sources, wireless environment sources, measurement bias, geometric sources, etc. This paper proposes the development of a framework that will allow mobile network operators to compare different location methods to ensure the provision of improved quality of service to the mobile user and optimized usage of infrastructure. This framework takes into consideration the error sources of the location methods based on specific geographic area.