Road map of the thesis
3.2 O perational Efficiency
The awareness of hidden situations over time on the DBN in Figure 6.4 comes as a result of acting using sampled probabilistic queries, shown as a set of equations (6.10). This reveals the local dynamics from the global behaviour. If the ESA can reveal changes in pH, then it is worth knowing the variability for the concentrations of chemical substances such as Chlorine (Cl) and Ammonia (NH3). These interactively reveal the transitional knowledge about pH, Chlorine and Ammonia from the domain of water quality management. It shows the likelihood of the next situations, which give insight into the actions to be taken by the decision-makers (or water quality managers).
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104 pr (pH t ?| RiverSize t = small, FluidVelocity t = high),
Pr(NH3t ?| RiverSize t = small, FluidVelocity t = high),
pr (pH t ?| RiverSize t = large, FluidVelocity t =high)
pr (Cl t ?| RiverSize t = large, FluidVelocity t = high) ∀t є T (6.10) In the first situation of equations (6.10), we want to know the most probable values of pH over time when the river size is small and when the fluid velocity is high. This is similarly repeated for the rest of the situations. The revealed states of knowledge for all hidden situations in equations (6.10) are therefore shown in Figures (6.6) – (6.9) accordingly. Having seen the situations over seasons, decisions can be made easily after knowing what was not known by answering the four questions of the SA theory about the chemical water substances.
Figure 6.6: Emergent Situation of pH from small rivers flowing at high velocity.
Detailed understanding and decision-making process about the pattern in Figure 6.6:
Q1: What is happening?
A1: The pH is highly alkaline before Winter but uniformly tends to neutral from Winter to Spring.
Q2: Why is it happening?
A2: The rise in alkalinity is a true reflection of the presence of toxic chemicals, which reduces concentrations at Winter perhaps due to effects of more rain.
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of Cape
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105 Q3: What will happen next?
A3: Supposing we are currently in Spring and since this is a seasonal variation, the pH will rise to about 8.29 in the next Summer. Similar reasoning is consistent as shown for other seasons.
Q4: What can I do about it?
A4: Before the next Summer, one can identify the actual chemical substances and their sources, which affect the rise of pH and moderate or prevent them from getting into the rivers.
Figure 6.7: Emergent Situation of Ammonia from small rivers flowing at high velocity.
Detailed understanding and decision-making process derived from the pattern in Figure 6.7:
Q1: What is happening?
A1: Ammonia concentration over the seasons is about 1.3 and it increases drastically in Autumn where toxicity suspiciously increases the pH in Figure 6.6, and is harmful to life in water.
Q2: Why is it happening?
A2: This might result from farmland activities (e.g. fertilizer application) around this type of river since Autumn is regarded as the planting season. Also, more fish metabolism and deaths suspiciously produce Ammonia over the seasons.
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of Cape
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106 Q3: What will happen next?
A3: Supposing we are currently in Summer, the Ammonia is projected to about 2.57 in Autumn but this is more than the water standards of about 0.5. Similar reasoning is consistent as shown for other seasons.
Q4: What can I do about it?
A4: Before Summer, farmers must be well educated and enforce pollution control measures to save lives in rivers.
Figure 6.8: Emergent Situation of pH from large rivers flowing at high velocity.
Detailed understanding and decision-making process derived from the pattern in Figure 6.8:
Q1: What is happening?
A1: The pH is very unstable over the seasons. It is alkaline in Summer but tends to be neutral in Autumn and gradually becomes highly alkaline in Spring.
Q2: Why is it happening?
A2: There is presence of more toxic chemicals suspected over the seasons except in Autumn, which shows a reflection of acidic chemicals.
University
of Cape
Town
107 Q3: What will happen next?
A3: Supposing we are currently in Winter, about 8.8 is anticipated as the pH in Spring. Similar reasoning is consistent as shown for other seasons.
Q4: What can I do about it?
A4: Similarly to Figure 6.7, the ESA provides the need for the early identification of the toxic chemical substances, which causes high pH in Spring.
Figure 6.9: Emergent Situation of Chlorine from large rivers flowing at high velocity.
Detailed understanding and decision-making process derived from the pattern in Figure 6.9:
Q1: What is happening?
A1: Chlorine is an acceptable 4.3 over the seasons but it dramatically increases to 16 in Autumn when its concentration suspiciously tends to make pH acidic. This excess Chlorine can lead to breathing difficulties for the aquatic animals, such as fish.
Q2: Why is it happening?
A2: Autumn has high chlorine since the season is dominated by agricultural practices, much of which is suspected to consist of high sewage treatment that dumps toxic chlorine into the river. Chlorine level is stable in other seasons probably because the intensity of sunlight is routinely measured.
University
of Cape
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108 Q3: What will happen next?
A3: Supposing there is still continued abusive sewage treatment which is harmful to the environment, anticipated value of Chlorine in Autumn will be around 16.
Q4: What can I do about it?
A4: The controlling agencies must enforce laws on land practices around this type of river to maintain Chlorine concentration with the maximum of 5.0.
The awareness can similarly be applied to other situations as required. Thus, the ESA suitably showed the results for variations in chemical concentrations of rivers in European countries. It is tremendously useful for understanding hidden patterns in various domains of interest.