Nagraadse studie vir die algemene praktisyn

No Abstrac

Software defined networking for radio telescopes: a case study on the applicability of SDN for MeerKAT

Scientific instruments like radio telescopes depend on high-performance networks for internal data exchange. The high bandwidth data exchange between the components of a radio telescope makes use of multicast networking. Complex multicast networks are hard to maintain and grow, and specific installations require modified network switches. This study evaluates Software Defined Networking (SDN) for use in the MeerKAT radio telescope to alleviate the management complexity and allow for a vendor-neutral implementation. The purpose of this dissertation is to verify that an SDN multicast network can produce suitable paths for data flow through the network and to see if such an implementation is easier to maintain and grow. There is little literature regarding SDN for radio telescope networks; however, there is considerable work where different aspects of SDN are discussed and demonstrated for video streaming. SDN with multicast for video streaming, although simpler, forms the background research. Considerable work was put into understanding and documenting the different aspects of a radio telescope affecting the data network. The telescope network controller generates the OpenFlow rules required by the SDN controller and is a new concept introduced in this work. The telescope network controller is fitted with two placement algorithms to demonstrate its flexibility. Both algorithms are suitable for the expected workload, but they produce very different traffic patterns. The two algorithms are not compared to one another, they were created to demonstrate the ease of adding domain specific knowledge to an SDN. The telescope network controller makes it easy to introduce and use new flow placement algorithms, thus making traffic engineering feasible for the radio telescope. Complex multicast networks are easier to maintain and grow with SDN. SDN allows customised packet forwarding rules typically unattainable with standard routing and other standard network protocols and implementations. A radio telescope with a software-defined data network is resilient, easier to maintain, vendor-neutral, and possesses advanced traffic engineering mechanisms

Simulated clinical scenarios: The experiences of Emergency Care Practitioner students

Background: Simulation education as a strategy is used extensively in Emergency Medical Care Departments. The literature in this field strongly suggests positive effects on patient safety and student-readiness. Simulation education strategies often fail to address the student experiences in the classroom. The aim of this study was to explore how Emergency Care Practitioner (ECP) students experience simulated clinical scenarios. Methods: This study was conducted at a South African University in the Gauteng province. Data was collected through semi-structured interviews. Convenience sampling was used to recruit participation. Data saturation occurred after six interviews. Open coding was used to code the transcripts. Results: ECP students experienced simulated clinical scenarios to be a highly beneficial teaching and learning experience, but experienced simulation as a nerve-racking assessment tool that requires excellent debriefing and feedback to improve its effectiveness. High-fidelity simulation scenarios, that are built on real-life context, are received most favourably by students. Conclusions: ECP Students find simulated clinical scenarios to be valuable in their education. To achieve a favourable simulation experience for ECP students excellent debriefing and feedback protocols need to be implemented. Availability of time to practise in the simulation laboratory is limited and students feel limited by this

For the students, by the students: Student perceptions of low cost medical moulage in a resource-constrained environment

Abstract: Introduction: Simulation-based learning affords participants the opportunity to practice high-acuity, low-incidence situations without risk to the patient. The realism of a simulated scenario is often referred to as fidelity. High levels of fidelity imply high levels of realism. One method of enhancing fidelity is the use of moulage. Commercially available moulage kits and professionally applied moulage are often expensive and therefore not practical in the resource-constrained environment. Cost-effective alternatives are required for the resourceconstrained environment. Methods: Students at a South African university used readily available, low cost materials to apply self-constructed, low cost moulage for a bandaging practical. A cross sectional design used a purpose-designed, validated questionnaire to gather data related to face and content validity of the self-constructed moulage. Frequency analysis formed the cornerstone of Likert-type quantitative data analysis. An open-ended question afforded participants the opportunity to express their own opinions related to the moulage experience. Results: The results revealed that there was both high face validity and high content validity of the self-constructed moulage. Participants found the activity enjoyable and a generally positive learning experience. The self-constructed moulage was realistic and added to the fidelity of the scenario. Participant confidence was improved and their engagement in the learning activity was enhanced. Participants found the self-constructed, low-cost moulage more realistic that commercial products that they had been exposed to. Conclusion: The use of low-cost, self-constructed moulage is a feasible and economically viable means of enhancing fidelity within the resource-constrained simulation setting. This technique is not necessarily limited to emergency medical care and can be used in other areas of healthcare simulation

Vaginale amebiase

No Abstract

NONLINEAR CONTROL STRATEGIES AND PLANNING FOR UNDERACTUATED OVERHEAD CRANES

Underactuated overhead cranes play an important role in engineering and construction, which also make nonlinear control strategies and planning on this basis become the current focus of academic research. Based on scholarly research findings, this paper carries out a theoretical study on nonlinear control strategies and planning for underactuated overhead cranes. To begin with, the underactuated system, underactuated overhead cranes and its nonlinear control are elucidated. Afterwards, the stabilization methods for front actuators are analyzed, and finally two nonlinear control methods are explored in the hope of providing some references for research in related fields

Advantages of using factorisation machines as a statistical modelling technique

Factorisation machines originated from the field of machine learning literature and have gained popularity because of the high accuracy obtained in several prediction problems, in particular in the area of recommender systems. This article will provide a motivation for the use of factorisation machines, discuss the fundamentals of factorisation machines, and provide examples of some applications and the possible gains by using factorisation machines as part of the statistician’s model-building toolkit. Data sets and existing software packages will be used to illustrate how factorisation machines may be fitted and in what context it is worth being used

Algorithms for estimating the parameters of factorisation machines

Since the introduction of factorisation machines in 2010, it became a popular prediction technique amongst machine learners who applied the method with success in several data science challenges such as Kaggle or KDD Cup. Despite these successes, factorisation machines are not often considered as a modelling technique in business, partly because large companies prefer tried and tested software for model implementation. Popular modelling techniques for prediction problems, such as generalised linear models, neural networks, and classification and regression trees, have been implemented in commercial software such as SAS which is widely used by banks, insurance, pharmaceutical and telecommunication companies. To popularise the use of factorisation machines in business, we implement algorithms for fitting factorisation machines in SAS. These algorithms minimise two loss functions, namely the weighted sum of squared errors and the weighted sum of absolute deviations using coordinate descent and nonlinear programming procedures. Using a simulation study, the above-mentioned routines are tested in terms of accuracy and efficiency. The prediction power of factorisation machines is then illustrated by analysing two data sets

Predicting postoperative haemoglobin changes after burn surgery

Background. Burn surgery is associated with significant blood loss and fluid shifts that cause rapid haemoglobin (Hb) changes during and after surgery. Understanding the relationship between intraoperative and postoperative (day 1) Hb changes may assist in avoiding postoperative anaemia and unnecessary peri-operative blood transfusion.Objective. To describe the Hb changes into the first day after burn surgery and to identify factors predictive of Hb changes that would guide blood transfusion decisions.Methods. This was a single-institution, retrospective cohort study that included 158 patients who had undergone burn surgery. Hb was measured at the start and end of surgery, and on the first day (16 - 32 hours) after surgery, and the results were analysed. Peri-operative factors (Hb at the end of surgery, total body surface area operated on (TBSA-op), fluid administration and intraoperative blood administration) were evaluated to determine their association with Hb changes on the first day after surgery.Results. The mean (standard deviation) preoperative Hb was 10.6 (2.29) g/dL, the mean postoperative Hb was 9.4 (2.01) g/dL, and the mean Hb on the first day after surgery was 9.2 (2.19) g/dL. Median total burn surface area was 7% (interquartile range 9%, min. 1%, max. 45%), with a mean body surface area operated on (debridement area plus donor area) of 9.7%. Of the 158 patients, 26 (16%) had an Hb <7 g/dL (transfusion trigger) on the first day after surgery. For patients with a high (≥9 g/dL), intermediate (≥7 - <9 g/dL), or low (<7 g/dL) Hb measurement at the end of burn surgery, those with an Hb below the transfusion trigger on the first day after burn surgery were 0%, 27%, and 75%, respectively. End-of-surgery Hb and TBSA-op strongly predicted the first day Hb level. In the intermediate group, 55% of patients with a TBSA-op ≥11% had an Hb below the transfusion trigger on the first day after surgery.Conclusion. Hb at the end of burn surgery was the best predictor of Hb on the first day after surgery. Patients with an Hb <7 g/dL remained as such on the first postoperative day. Half of the patients with an end-of-surgery Hb ≥7 - <9 g/dL and who had ≥11% TBSA-op had an Hb <7 g/dL on the first postoperative day