A Boxology of Design Patterns for Hybrid Learning and Reasoning Systems

We propose a set of compositional design patterns to describe a large variety of systems that combine statistical techniques from machine learning with symbolic techniques from knowledge representation. As in other areas of computer science (knowledge engineering, software engineering, ontology engineering, process mining and others), such design patterns help to systematize the literature, clarify which combinations of techniques serve which purposes, and encourage re-use of software components. We have validated our set of compositional design patterns against a large body of recent literature.Comment: 12 pages,55 reference

Education, ethics and values : A response to Peter Blaze Corcoran’s keynote address, EEASA 2003

This paper is written in response to the Keynote Adress on the Earth Charter presented by Peter Blaze Corcoran at the EEASA 2003 Conference in Namibia. It draws attention to the significance of ethical debates in education and emphasises the need for careful attention to the way in which educators approach values education. In particular the paper considers the Earth Charter critically, and notes that while there is much value in the principles of the Earth Charter for guiding educational practice, educators should also consider some of the dilemmas of simply appropriating univeral ethical frameworks to guide practice

A quantitative analysis of the influence of a household’s income, access to food and education level on the prevalence of diabetes in adults: a secondary analysis of data from the South African General Household Survey of 2014.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.As diabetes mellitus is becoming a burgeoning epidemic in South Africa, preventative measures are required to stop its prevalence in adults. Hence, the aim of this study is to explore the South African General Household Survey data to try and understand the influence of a household’s average per capita income, access to food and the head of the household’s average educational level on the prevalence of diabetes in adults. It specifically looks at the data from a household level and not an individual level and uses literature to support and give meaning to the results. Furthermore, this study used bivariate analysis to determine if there is a difference between adult residents who have diabetes and adult residents who do not have diabetes. In addition to this, a multiple logistic regression was conducted to explain any significant effect of the three key variables under study. Results indicate that there is a difference in all three variables between households with adult residents with diabetes and households without adult residents with diabetes. Furthermore, only the head of the household’s average education level had a significant effect on the prevalence of diabetes. These findings suggest that there is some influence on the prevalence of diabetes for individuals who have higher levels of education. This entry level study tried to make sense of these findings in terms of literature to inform future and more direct in-depth research which is urgently required to understand and combat the increasing prevalence of diabetes in South Africa. Significantly, the conclusion of this study suggests that the General Household Survey incorporates both type I diabetes mellitus and type II diabetes mellitus in their questionnaire, as these are unique diseases with their own risk factors and which require different preventative measures

Viewpoint: Education, Ethics and Values- A Response to Peter Blaze Corcoran’s Keynote Address, EEASA 2003

This paper is written in response to the Keynote Adress on the Earth Charter presented by Peter Blaze Corcoran at the EEASA 2003 Conference in Namibia. It draws attention to the significance of ethical debates in education and emphasises the need for careful attention to the way in which educators approach values education. In particular the paper considers the Earth Charter critically, and notes that while there is much value in the principles of the Earth Charter for guiding educational practice, educators should also consider some of the dilemmas of simply appropriating univeral ethical frameworks to guide practice

Investigating stimulus-driven selective attention inside visual working memory

Multiple objects can exist within (visual) working memory simultaneously, and internal selective attention is required to select amongst those objects. It is known this internal selection can occur in a goal-driven manner (Griffin & Nobre, 2003; van Ede et al., 2019), but the question remains whether this can also occur in a stimulus-driven manner. To answer this question, van Ede et al. (2020) developed a retrocue visual working memory task. They were able to induce attentional shifts with a completely uninformative retrocue, an effect that is best explained by the occurrence of stimulus-driven internal attention. Using eye-tracking, van Ede et al. showed that these attentional shifts were accompanied by a shift in gaze position towards the original location of the currently active memory item. Liu et al. (2022) showed that an internal attentional shift is often (also) accompanied by a bias in microsaccade direction. However, the retrocue employed by van Ede et al. was only completely uninformative in one third of all trials, creating the possibility that the retrocue retained some implied informational value for participants. Our main research question therefore is: is a completely uninformative cue capable of and sufficient for creating an involuntary attentional-capture effect? If so, is this again reflected in an ocular signature consisting of a bias in gaze position and microsaccade direction? And is the behavioural effect that results from the attentional capture due to a benefit to the cued memory item, a cost to the uncued memory item, or a combination of both? To answer these questions, the visual working memory task from van Ede et al. (2020) was employed after changing it in two critical ways. Based on the previous research we expected to find a behavioural attentional-capture effect, by observing less reproduction error and/or shorter decision times when the capture cue colour-matched the eventually probed item. We also expected that this behavioural effect would be accompanied by both a bias in gaze position and microsaccade direction towards the cued memory item. Two separate experiments were performed for this research, which only differed in the shape of the capture cue. Experiment 1 produced no significant effect of capture cue congruency on decision times or accuracy, and this was accompanied by an extremely small, but significant, gaze bias. No significant microsaccade bias was found. Experiment 2 produced a significant effect of congruency on decision times, but not on accuracy: participants responded faster in congruent trials than in both neutral and incongruent trials. On group-level, this behavioural effect was again accompanied by a small, but significant, gaze bias, and no significant microsaccade bias was found. The relationship between behavioural effect and ocular bias was further investigated by calculating a decision time effect size and a microsaccade bias effect size. A median-split of decision time effect size showed a significant microsaccade bias was present in the above-median decision time effect group. This microsaccade bias occurred within the expected timeframe, as based on previous research by Liu et al. (2022). We concluded that a completely uninformative capture cue is capable of and sufficient for creating an involuntary attentional-capture effect within a visual working memory task. In a subset of participants this was also reflected in a significant bias in microsaccade direction, but this did not occur at a group-level. Finally, it seems the behavioural effect is due to a benefit for cued items, at no cost to uncued items. The current experiment complements earlier work by providing further proof that stimulus-driven internal attention does indeed exist and is sometimes accompanied by an ocular signature, consisting of at least a microsaccade direction bias. This research emphasises that the external world plays an important role in shaping the contents of our mind

Human immunodeficiency virus type-1 distribution in South Africa and the relevance of genetic diversity on vaccine design

The overall aim of this project was to investigate HIV-1 genetic diversity in South Afri ca and to characterise the immune response in mice to a South African subtype C gp120. To investigate the relationship between subtype and mode of transmission, samples were collected from individuals infected by heterosexual and male homosexual transmission from patients attending local HIV/AIDS clinics in Cape Town (n=49) and Bloemfontein (n=4). Isolates were subtyped using heteroduplex mobility assay (HMA) based on the V3-V5 region of the env geneusing reference plasmids (2 B, 2 C and 1 D) representative of local subtypes. HMA identified four env subtypes: A, B, C and D. Subtype B viruses were found in 92.9% (26/28) of the male homosexual/bisexual group and subtype C viruses in 77.2% (17 /22) of the heterosexual group. Subtype B viruses were also identified in two heterosexual patients, one patient infected by blood transfusion and in two patients with. unknown mode of transmission. Subtype D viruses were found in one male homosexual patient and one heterosexual patient and a husband and wife couple were infected with subtype A viruses. A significant association between subtype and mode of transmission (p=<0.0001) was identified, confirming two independent epidemics. To determine the subtype distribution of HIV within urban heterosexual populations throughout South Africa, samples were collected from women attending antenatal clinics in Johannesburg (n=34), Pretoria (n=S) and Durban (n=20). Samples from Bloemfontein (n=24) were taken from individuals attending an HIV/AIDS clinic. All eighty-three samples were subtyped by HMA in the env region as before. The predominant subtype circulating within the urban heterosexual population throughout South Africa was identified as subtype C (92.8%) although subtype B was also detected (7.2%). It may thus be beneficial if a HIV vaccine for South Africa is based on a subtype C model. In addition, a rapid method for identification of HIV-1 gag subtypes was developed based on restriction fragment length polymorphism (RFLP) analysis of 400bp (p17) or 650bp (p17 and 5' p24) long PCR fragments. This strategy was appl i ed to eighty-six samples (Cape Town n=47, Johannesburg n=20, Bloemfontein n=17 and Durban n=2) previously subtyped by either sequence analysis of the gag p17 region (n=31), heteroduplex mobility assay (HMA) based on the env gene (n=76), or both (n=21). RFLP analysis identified two subtype A, twenty-five subtype B, fifty-eight subtype C and one subtype D isolates. There were no discrepancies between RFLP and sequence gag subtypes, demonstrating the reliability of this method and no discordance between gag RFLP subtypes and env HMA subtypes, indicating no recombinant viruses in the genomic regions analysed

Structure preserving specification languages for knowledge-based systems

Much of the work on validation and verification of knowledge based systems (KBSs) has been done in terms of implementation languages (mostly rule-based languages). Recent papers have argued that it is advantageous to do validation and verification in terms of a more abstract and formal specification of the system. However, constructing such formal specifications is a difficult task. This paper proposes the use of formal specification languages for KBS-development that are closely based on the structure of informal knowledge-models. The use of such formal languages has as advantages that (i) we can give strong support for the construction of a formal specification, namely on the basis of the informal description of the system; and (ii) we can use the structural correspondence to verify that the formal specification does indeed capture the informally stated requirements

Accelerating Scientific Discovery by Formulating Grand Scientific Challenges

One important question for science and society is how to best promote scientific progress. Inspired by the great success of Hilbert's famous set of problems, the FuturICT project tries to stimulate and focus the efforts of many scientists by formulating Grand Challenges, i.e. a set of fundamental, relevant and hardly solvable scientific questions.Comment: To appear in EPJ Special Topics. For related work see http://www.futurict.eu and http://www.soms.ethz.c

A comparison of languages which operationalise and formalise {KADS} models of expertise

In the field of Knowledge Engineering, dissatisfaction with the rapid-prototyping approach has led to a number of more principled methodologies for the construction of knowledge-based systems. Instead of immediately implementing the gathered and interpreted knowledge in a given implementation formalism according to the rapid-prototyping approach, many such methodologies centre around the notion of a conceptual model: an abstract, implementation independent description of the relevant problem solving expertise. A conceptual model should describe the task which is solved by the system and the knowledge which is required by it. Although such conceptual models have often been formulated in an informal way, recent years have seen the advent of formal and operational languages to describe such conceptual models more precisely, and operationally as a means for model evaluation. In this paper, we study a number of such formal and operational languages for specifying conceptual models. In order to enable a meaningful comparison of such languages, we focus on languages which are all aimed at the same underlying conceptual model, namely that from the KADS method for building KBS. We describe eight formal languages for KADS models of expertise, and compare these languages with respect to their modelling primitives, their semantics, their implementations and their applications. Future research issues in the area of formal and operational specification languages for KBS are identified as the result of studying these languages. The paper also contains an extensive bibliography of research in this area