Reinforcement Learning with Parameterized Actions

We introduce a model-free algorithm for learning in Markov decision processes with parameterized actions-discrete actions with continuous parameters. At each step the agent must select both which action to use and which parameters to use with that action. We introduce the Q-PAMDP algorithm for learning in these domains, show that it converges to a local optimum, and compare it to direct policy search in the goal-scoring and Platform domains.Comment: Accepted for AAAI 201

An exploration of young adult males' perceptions of non-resident fathers.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.Research on fatherhood has become an area of increasing interest internationally; however, this area remains under-researched in South Africa. Given the increase in father-absent households in South Africa and its severe effects on children, the issue of non-resident fathers requires immediate attention. This study sought to address the paucity of research on this problem by examining the subjective experiences and perceptions of participants in relation to their non-resident fathers. A qualitative methodology was adopted, and semi-structured interviews were conducted with 10 young adult males who have or had a non-resident father. The results of the study revealed commonalities and contrasts within and across interviews; the contradictions and conflicts that emerged were also explored. This study highlights the unique roles that non-resident fathers play, which go beyond the financial provider role. Specific factors that either facilitate or impede the father-son relationship and how father involvement shapes children's well-being were explored. The results show the strong emotional need that boys have for their fathers and the desire for a close, intimate and fulfilling relationship between a father and son. It is clear that non-resident fathers can and should play a major role in their sons' lives

Caught in the web : an analysis of South Africa's response to the emerging global information policy regime

Includes bibliographical references (leaves 122-126).This study provides a descriptive analysis of South Africa's response to the emerging global information policy regime. Compelled by a combination of hegemonic influences and its own self interest, this study argues that South Africa accepted the liberalising commitments of the emerging global information policy regime vis-a-vis the World Trade Organization Agreement on Basic Telecommunications. As a contribution to understanding inter-state cooperation in international relations, regime theory is utilised as the theoretical framework. The regime framework is used to explain the motivations behind South Africa's intention to liberalise its telecommunications sector as a result of power dynamics in the international system. The findings from the qualitative analysis note that South Africa's response is motivated by systemic and domestic factors. A willingness to enter the information economy and fulfil domestic social development means that South Africa has to balance its obligations to the WTO with the commitments to improve its domestic accessibility concerns. As a developing country with inadequate conditions for liberalisation, South Africa was unable to stop the strategic equity partners from capitalising on the poorly regulated telecommunications environment. The unfavourable result of high tariff charges and low fixed-line connectivity can be attributed to privatisation initiatives and lack of political will to promote competition. South Africa is in the midst of dramatic change in its telecommunications sector which is aided by technological convergence, further privatisation of the incumbent and the introduction of the Second Network Operator. The international scope of this study means that liberalisation is part of South Africa's broader commitments to the emerging global information policy regime. Entering the information economy is conditional on the successful implementation of international liberalisation policies so that the required investment and skills can assist in providing universal service to the majority of South Africa citizens. However, implementation requires a fair market structure, independent regulation and low interconnection charges. Without these important structures in place, this study notes that the goal of participation in the information economy and economic growth as a result of effective telecommunication utilisation is a distant reality

Convergence

Poetry inspired by scienc

Parallelisation of EST clustering

Master of Science - ScienceThe field of bioinformatics has been developing steadily, with computational problems related to biology taking on an increased importance as further advances are sought. The large data sets involved in problems within computational biology have dictated a search for good, fast approximations to computationally complex problems. This research aims to improve a method used to discover and understand genes, which are small subsequences of DNA. A difficulty arises because genes contain parts we know to be functional and other parts we assume are non-functional as there functions have not been determined. Isolating the functional parts requires the use of natural biological processes which perform this separation. However, these processes cannot read long sequences, forcing biologists to break a long sequence into a large number of small sequences, then reading these. This creates the computational difficulty of categorizing the short fragments according to gene membership. Expressed Sequence Tag Clustering is a technique used to facilitate the identification of expressed genes by grouping together similar fragments with the assumption that they belong to the same gene. The aim of this research was to investigate the usefulness of distributed memory parallelisation for the Expressed Sequence Tag Clustering problem. This was investigated empirically, with a distributed system tested for speed against a sequential one. It was found that distributed memory parallelisation can be very effective in this domain. The results showed a super-linear speedup for up to 100 processors, with higher numbers not tested, and likely to produce further speedups. The system was able to cluster 500000 ESTs in 641 minutes using 101 processors

Internal factorisation systems

We introduce internal factorisation systems for internal categories. We recall the definitions and theory of internal categories and factorisation systems. We develop a diagrammatic calculus of pullbacks for ease of internal calculation. To define an internal factorisation system we define and study the subobjects of isomorphisms, an internalisation of the class of isomorphisms of a category. We provide an abstract example of an internal factorisation system. We then internalise various properties of factorisation systems, such as the two components determining each other, the cancellation properties and the essential uniqueness of factorisations, and show that an internal factorisation system satisfies these internal conditions

Ameloblastoma of the mandible: A radiological and clinical study at the University of the Western Cape Oral Health Centre

Magister Chirurgiae Dentium - MChDAmeloblastoma is the most common benign tumour of odontogenic origin and presents five times more in the mandible than in the maxilla (Reichardt et al. 1995). Although benign, it exhibits an invasive behavioural growth pattern with a high rate of recurrence if not managed appropriately. Ameloblastoma occurs in all age groups, but is most common in patients between the ages of 20 and 40 years. Males and females are equally affected. Clinically, ameloblastoma presents as a slow-growing, painless tumour, which if left untreated, can grow to enormous proportions. Radiographically, the lesion presents as either multilocular or unilocular radiolucency. The internal appearance of multilocular lesions may resemble a soap-bubble, honeycomb or spider-like pattern. Combinations of these patterns are not unusual

Convergence

Poetry inspired by scienc

Public sector pharmacists' perception of the public sector performance management system

Performance Management aims to develop the employee and ensure that the work which the employee does is in line with organisational goals. However, many managers and employees do not like performance management systems and very often, for this reason, such a system does not succeed in meeting the organisation’s goals. The aim of this study was to determine the perceptions towards the performance management system of pharmacists working in the public sector. A questionnaire was compiled and pharmacists working in all public sector hospitals, provincial and municipal clinics and medical depots were asked to complete the questionnaire. The response rate was 66 percent. Seventy three percent of respondents had never undergone a performance evaluation, 75 percent stated it did not motivate them, 62.5 percent felt it did not improve poor performance, 90.6 percent felt the Performance Appraisal System did not reward good performance sufficiently and 63.6 percent felt it did not help with career progression. Seventy eight percent believed that the Performance Appraisal System did not effectively measure the pharmacists’ performance, and 82 percent felt that the System needed to be developed further. At least four evaluations should have been completed per year, yet 85 percent of respondents had experienced three or fewer evaluations since the System had been introduced. The analysis of the responses indicated that there was great dissatisfaction with the current performance management system. A few of the reasons are that the system in place did not effectively measure the pharmacists performance, that additional work done was not recognised, and that the process was extremely time-consuming. It may be concluded that the government needs to address the current problems being experienced with this system, as at present, it is not meeting the objectives it was intended to meet