Accessibility in a post-apartheid city: Comparison of two approaches for the computation of accessibility indicators

Accessibility indicators take land use, the transport system, and their interdependencies into account in a holistic fashion. In many areas, however, spatial data to perform accessibility calculations are hard to obtain or not available at all. Freely available volunteered geographic information (VGI) like from OpenStreetMap (OSM), which is increasingly becoming a world-wide standard for geo-spatial data, may be a solution to this problem. In fact, some accessibility studies use data from OSM to create representations of the transport network and to perform network-based computations. In this paper, two approaches for accessibility assessment for Nelson Mandela Bay Municipality in South Africa are presented. The approaches possess different levels of utilization of OSM data which both exceed the use of OSM data for network creation. In the first approach, the transport network as well as locations and types of activity facilities are taken from OSM. Additionally, a synthetic population is created based on a census. The corresponding travel demand is generated based on a travel survey. Local expert knowledge is applied to design a household-specific accessibility indicator that takes into account various characteristics of travel and land use, such as travel time to work and/or education, travel time to the nearest health/shopping facility, availability of different transport options, and availability of various facilities within walking distance. Weights are used to combine the respective values of aforementioned characteristics into a composite, household-based accessibility score. This approach appears particularly suitable in the South African context where housing locations and travel characteristics are highly diverse among the population. The second approach relies exclusively on OSM data, which is -- as before -- used to create the network and activity facilities in the model. The approach applies an econometric accessibility indicator, which calculates the accessibility of a given measuring point as the weighted sum over the utilities of all opportunities including the costs of reaching them. In contrast to the first approach, no synthetic population, but only household locations -- collected from OSM in the same way as (other) activity facilities -- are used for the calculation. The approach is highly portable since no input data other than those from OSM are used. It is found that the second approach, though being much more lightweight in terms of data requirements, yields the same quality of insights concerning accessibilities of different areas of the region. Both approaches detect areas where levels of accessibility deprivation are high and where interventions in the transport-land-use system are advisable. Consequently, the paper is a contribution to accessibility analyses based on easily obtainable and ubiquitously available OSM data to obtain similar results as with respective approaches based on traditional spatial data

The pitfalls of postoperative theatre to intensive care unit handovers: a review of the current literature

Postoperative handovers present a critical step in the management of intensive care unit (ICU) patients. There are many challenges in the transportation of unstable patients with complex medical histories from theatre to the ICU, and the subsequent transfer of responsibility for care from one group of caregivers to another. Communication between the providers of the handover report (anaesthetists, surgeons and theatre nursing staff) and receivers of the report (ICU physicians and ICU nursing staff) is often poor. The unstructured presentation of information, the noisy ICU environment, and discussions between healthcare workers from different disciplines at different levels of training adds to the burden of communication. The handover report may be seen as a sentinel event in the ICU patient’s stay. ICU staff use the handover process as an important source of information to coordinate management input from multiple disciplines. Despite its importance, the practice of a structured postoperative handover protocol in our region’s hospitals is non existent. The authors reviewed the current literature to better understand the challenges facing proper handover processes and suggest some interventional strategies

Accessibility in a Post-Apartheid City: Comparison of Two Approaches for Accessibility Computations

Many authors argue that issues related to interpretability, lack of data availability, and limited applicability in terms of policy analysis have hindered a more widespread use of accessibility indicators. Aiming to address these aspects, this paper presents two accessibility computation approaches applied to Nelson Mandela Bay in South Africa. The first approach, a household-based accessibility indicator, is designed to account for the high diversity both among the South African society and in terms of settlement patterns. Besides OpenStreetMap (OSM) as its main data source, this indicator uses a census and a travel survey to create a synthetic population of the study area. Accessibilities are computed based on people's daily activity chains. The second approach, an econometric accessibility indicator, relies exclusively on OSM and computes the accessibility of a given location as the weighted sum over the utilities of all opportunities reachable from that location including the costs of overcoming the distance. Neither a synthetic population nor travel information is used. It is found that the econometric indicator, although associated with much lower input data requirements, yields the same quality of insights regarding the identification of areas with low levels of accessibility. It also possesses advantages in terms of interpretability and policy sensitivity. In particular, its exclusive reliance on standardized and freely available input data and its easy portability are a novelty that can support the more widespread application of accessibility measures

The production performance of two pig genotypes on varying levels of dietary protein

Please read the abstract in the section 00front of this documentDissertation (MSc (Agric))--University of Pretoria, 2006.Animal and Wildlife Sciencesunrestricte

The effect of vehicle load on urban freight emissions

Several city logistics initiatives focus on lowering last-mile deliveries’ environmental impacts. And here, the impact is often the total (absolute) pollutants emitted by urban goods vehicles and the population's exposure to those pollutants. Some of these interventions include the conversion of traditional fleets to clean(er) fuels or imposing vehicle access restrictions, based on emission standards, in the form of (ultra) low emission zones. Many of these interventions rely on models to predict and evaluate, a priori, what the impact will be. But, like all models, assumptions must be made, resulting in predicted results underestimating actual emissions. For urban logistics, more than for private cars, the literature shows a substantial difference between the predicted and tail-pipe emissions for most pollutants. This paper builds on prior research and shows the cargo load's nonlinear effect on emissions in an urban environment.The University of Pretoria, the Department of Science and Innovation through their Waste RDI Roadmap and the National Research Foundation, South Africa.http://www.journals.elsevier.com/transportation-research-procediahj2024Industrial and Systems EngineeringSDG-09: Industry, innovation and infrastructureSDG-11:Sustainable cities and communitie

A broadband 180° hybrid ring coupler using a microstrip-to-slotline inverter

A new broadband 180° hybrid ring coupler with a Chebyshev return loss response, implemented in microstrip line, and a phase inverter using microstripto- slotline transitions, is presented. The transitions were constructed using via short circuits and optimized radial slot stubs. The manufactured prototype was found to operate over a 118% bandwidth in the frequency range 0.72-2.8 GHz.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-27602016-09-30hb201

The survivability of cycling in a co-evolutionary agent-based model

DATA AVAILABILITY : The datasets generated and analysed during the current study are not publicly available because they constitute an excerpt of research in progress but are available from the corresponding author upon reasonable request.Many cities plan to grow cycling as a prominent mode to improve accessibility and environmental and financial sustainability. However, relatively few cities have made meaningful headway in this direction. Policymakers would be more inclined to implement the necessary interventions when they have certainty about potential demand, especially knowing where it is located in space. This paper introduces an approach to estimating potential cycling demand using agent-based modelling to determine who may benefit from switching from their current modes to cycling. People benefit when they obtain a similar or higher travel utility score when cycling between their daily activities than when using their existing modes. The model is based on individual mode selection, that all activities in the trip chain are included and can include detailed road and cycle network elements. The co-evolutionary mechanisms within the agent-based simulation allow us to test the potential for cycling relative to the performance of other modes on the network. The case for Cape Town, South Africa, shows that about 32% of those that travel would benefit from cycling based on their utility score. Understanding that travel time benefits are not the only criteria for mode selection, we apply a rejection sampling algorithm based on demographic factors to demonstrate that a more realistic, or pragmatic, cycling potential for Cape Town is in the region of 8%. The results also show that more than 46% of the observed pragmatic demand for cycling is concentrated in an area covering less than 7% of the study area. This has practical implications for policymakers to target interventions both in space and towards specific demographic market segments.https://link.springer.com/journal/11116hj2024Industrial and Systems EngineeringSDG-09: Industry, innovation and infrastructureSDG-11:Sustainable cities and communitie

A people-centred view on paratransit in South Africa

Paratransit provides a valuable service offering as a flexible and substitutional mode between formal transit and private car. When it evolves to compete with more formal transit modes, efforts are made to formalise it. As in many developing countries, the South African government generally views paratransit as a necessary nuisance, emerging and evolving in the absence of more formal transit services. Our paper aims to contribute by providing a more comprehensive context for the South African case: how specific Apartheid laws contributed to the formation of the mode and how deregulation provided a fertile ground for its exponential growth. The industry has evolved into an informal yet well-organised system that dominates the local transit market. Contrary to the popular view that the industry is an amorphous whole, this paper aims to create a more people-centred view of an industry that is made up of individuals trying to carve an existence in a harsh economic environment. We show how, if approached correctly, paratransit is more likely part of the land use and transport solution, and not a problem as it is often perceived to be.The second author was funded through the Mobility Cultures in Megacities fellowship program, a joint initiative between the Technical University of Munich and the Institute for Mobility Research (ifmo), a research facility of the BMW Group.http://www.elsevier.com/locate/citieshj2014ai201

Testing self-perception theory with agent-based simulation

Paper presented at the 12th International Workshop on Agent-based Mobility, Traffic and Transportation Models, Methodologies and Applications (ABMTrans 2023) March 15-17, 2023, Leuven, Belgium.Conventional wisdom is that a person's attitude towards an issue dictates their behaviour. In contrast, self-perception theory accounts for how a person forms their attitude. In the context of this paper, the theory asserts that a person can, in the absence of prior experience, establish an attitude towards cycling based on observing their own, hopefully, positive experience. The adaptive agent-based model, MATSim, allows one to test the self-perception theory. The case study in Cape Town, South Africa, demonstrates that as much as 7.8% of people introduced to cycling will experience it as positive, opening the door for adoption.https://www.journals.elsevier.com/procedia-computer-sciencehj2023Industrial and Systems Engineerin

Applying min-max k postmen problems to the routing of security guards

The most essential and alluring characteristic of a security estate is the estate's ability to provide 24-h security to its residents, of which the continual patrolling of roads and paths is vital. The objective of this paper is to address the lack of sufficient patrol route design procedures by presenting a tabu search algorithm capable of generating multiple patrol routes for an estate's security guards. The paper shows that the problem of designing these routes can be modelled as an Arc Routing Problem, specifically as min-max k postmen problems. The algorithm is illustrated with a real problem instance from an estate in Gauteng, South Africa. The patrol routes generated by the algorithm provide a significant improvement in the even patrolling of the road network, and a more balanced work distribution among guards. The algorithm is also tested on several benchmark problems from literature.http://www.palgrave-journals.com/jors/index.htm