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02 July 2019 | Story Leonie Bolleurs
Edwin Skhosana
Edwin Skhosana is working hard to become a successful and competent actuary one day. With him is his lecturer, Dr Michael von Maltitz.

Edwin Skhosana, an Actuarial Sciences student, was described by his lecturer, Dr Michael von Maltitz of the Department of Mathematical Statistics and Actuarial Science, as ‘very quiet’ in his Causal Inference class. 

This may sound like a compliment, but it’s not.

For Dr Von Maltitz, being quiet is definitely not encouraged – not with the new teaching methods applied in class.

“See, my class is all about engagement – getting the students to watch videos on the topics, read about the methods in question, and then come to class to grill me about things they don’t understand. This change in teaching method is extremely disconcerting for many Mathematical students, who have up until now only been taught in the ‘memorise-regurgitate’ form they had ever since the start of high school,” he explains.

Future success


“My goal is to get the students to a level of understanding where they can sit down with me or with an expert in the field and have a conversation about the Mathematical Statistics topics that I teach. This is a very difficult task in such a technical module, and few students ever feel comfortable enough to engage with me actively in class in this way,” Dr Von Maltitz points out. 

Edwin is working hard towards applying the skills and knowledge he has obtained at university to become a successful and competent actuary one day. 

An important turning point was when it dawned on him how the things discussed in class could find an important practical application in so many fields.  

“This suddenly drove a spontaneous fascination in my mind that led me to engage with Dr Von Maltitz,” the previously quiet Edwin explains.

And everything changed.

Desperate to learn

Dr Von Maltitz explains: “Edwin came to my office to ask some questions. The incredible thing was that he sat down, and a conversation about the Mathematics, the foundations, and the methods just flowed between us. I have seldom had such an insightful chat about my module with a student. It was like a cascade of information just fell into place for Edwin.”

Although he sometimes still experiences his studies as challenging and grapples to adapt to the various styles of lecturing from different lecturers, Edwin now has hope for his class in Causal Inference. 

“I think Dr Von Maltitz’s way of presenting in class is excellent. It is, however, hard to grasp if you are still anchored in the old way of cramming, because he wants you to understand and be able to apply what he teaches,” says Edwin.

“It was just wonderfully refreshing to see someone so desperate to learn something (rather than just wanting to get a degree), and then actually managing to turn around a bad semester mark into such a river of understanding,” Dr Von Maltitz concludes.

Dr Michael von Maltitz
Dr Micheal von Maltitz

News Archive

Research helps farmers save with irrigation
2017-02-15

Description: Irrigation research Tags: Irrigation research

Marcill Venter, lecturer in the Department of
Agricultural Economics at the University of the
Free State, has developed the mathematical
programming system, Soil Water Irrigation
Planning and Energy Management in order to
determine irrigation pump hours.
Photo: Rulanzen Martin

Her advice to farmers is that they should make sure they are aware of the total cost (investment and operating costs) of an irrigation system. In most cases the investment cost is low, but the operating cost over the lifetime of the system is high.

“It is very important to have a look at the total cost and to install the most economic system,” says Marcill Venter, lecturer at the University of the Free State (UFS), who has done research on the economic sustainability of water-pipe systems.

Irrigation systems important components for farming
This research comes at a time when many farmers are relying on their irrigation systems due to persistent drought and low rainfall during 2016. South Africa has also experienced an abnormal increase in electricity tariffs in recent years. Due to tariff increases which threaten the future profitability of irrigation producers, the Water Research Commission (WRC) has launched and financed a project on the sustainable management of irrigation farming systems. “I had the opportunity to work on the project as a researcher,” says Venter.

The heart of every irrigation system is the water pipes that bring life to crops and livestock, and this is what Venter’s research is about. “Water pipes are part of the whole design of irrigation systems. The design of the system impact certain factors which determine the investment and operating costs,” she says.

Mathematical system to help farmers
Venter and Professor Bennie Grové, also from the Department of Agricultural Economics at the UFS, designed the Soil Water Irrigation Planning and Energy Management (SWIP-E) programming model as part of the WRC’s project, as well as for her master’s degree. “The model determines irrigation pump hours through a daily groundwater budget, while also taking into account the time-of-use electricity tariff structure and change in kilowatt requirements arising from the main-line design,” says Venter. The model is a non-linear programming model programmed in General Algebraic Modeling System (GAMS).

Design of irrigation system important for sustainability

The main outcome of the study is that the time-of-use electricity tariff structure (Ruraflex) is always more profitable than the flat-rate structure (Landrate). The interaction between the management and design of a system is crucial, as it determines the investment and operating costs. Irrigation designers should take the investment and operating cost of a system into account during the design process. The standards set by the South African Irrigation Institute (SAII) should also be controlled and revised.

Water-pipe thickness plays major role in cost cuts
There is interaction between water-pipe thickness, investment and operating costs. When thinner water pipes are installed, it increases the friction in the system as well as the kilowatt usage. A high kilowatt increases the operating cost, but the use of thinner water pipes lowers the investment cost. Thicker water pipes therefore lower the friction and the kilowatt requirements, which leads to lower operating costs, but thicker pipes have a higher investment cost. “It is thus crucial to look at the total cost (operating and investment cost) when investing in a new system. Farmers should invest in the system with the lowest total cost,” says Venter.

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