Evolutionary program induction directed by logic grammars.

by Wong Man Leung.Thesis (Ph.D.)--Chinese University of Hong Kong, 1995.Includes bibliographical references (leaves 227-236).List of Figures --- p.iiiList of Tables --- p.viChapter Chapter 1 : --- Introduction --- p.1Chapter 1.1. --- Automatic programming and program induction --- p.1Chapter 1.2. --- Motivation --- p.6Chapter 1.3. --- Contributions of the research --- p.8Chapter 1.4. --- Outline of the thesis --- p.11Chapter Chapter 2 : --- An Overview of Evolutionary Algorithms --- p.13Chapter 2.1. --- Evolutionary algorithms --- p.13Chapter 2.2. --- Genetic Algorithms (GAs) --- p.15Chapter 2.2.1. --- The canonical genetic algorithm --- p.16Chapter 2.2.1.1. --- Selection methods --- p.21Chapter 2.2.1.2. --- Recombination methods --- p.24Chapter 2.2.1.3. --- Inversion and Reordering --- p.27Chapter 2.2.2. --- Implicit parallelism and the building block hypothesis --- p.28Chapter 2.2.3. --- Steady state genetic algorithms --- p.32Chapter 2.2.4. --- Hybrid algorithms --- p.33Chapter 2.3. --- Genetic Programming (GP) --- p.34Chapter 2.3.1. --- Introduction to the traditional GP --- p.34Chapter 2.3.2. --- Automatic Defined Function (ADF) --- p.41Chapter 2.3.3. --- Module Acquisition (MA) --- p.44Chapter 2.3.4. --- Strongly Typed Genetic Programming (STGP) --- p.49Chapter 2.4. --- Evolution Strategies (ES) --- p.50Chapter 2.5. --- Evolutionary Programming (EP) --- p.55Chapter Chapter 3 : --- Inductive Logic Programming --- p.59Chapter 3.1. --- Inductive concept learning --- p.59Chapter 3.2. --- Inductive Logic Programming (ILP) --- p.62Chapter 3.2.1. --- Interactive ILP --- p.64Chapter 3.2.2. --- Empirical ILP --- p.65Chapter 3.3. --- Techniques and methods of ILP --- p.67Chapter Chapter 4 : --- Genetic Logic Programming and Applications --- p.74Chapter 4.1. --- Introduction --- p.74Chapter 4.2. --- Representations of logic programs --- p.76Chapter 4.3. --- Crossover of logic programs --- p.81Chapter 4.4. --- Genetic Logic Programming System (GLPS) --- p.87Chapter 4.5. --- Applications --- p.90Chapter 4.5.1. --- The Winston's arch problem --- p.91Chapter 4.5.2. --- The modified Quinlan's network reachability problem --- p.92Chapter 4.5.3. --- The factorial problem --- p.95Chapter Chapter 5 : --- The logic grammars based genetic programming system (LOGENPRO) --- p.100Chapter 5.1. --- Logic grammars --- p.101Chapter 5.2. --- Representations of programs --- p.103Chapter 5.3. --- Crossover of programs --- p.111Chapter 5.4. --- Mutation of programs --- p.126Chapter 5.5. --- The evolution process of LOGENPRO --- p.130Chapter 5.6. --- Discussion --- p.132Chapter Chapter 6 : --- Applications of LOGENPRO --- p.134Chapter 6.1. --- Learning functional programs --- p.134Chapter 6.1.1. --- Learning S-expressions using LOGENPRO --- p.134Chapter 6.1.2. --- The DOT PRODUCT problem --- p.137Chapter 6.1.2. --- Learning sub-functions using explicit knowledge --- p.143Chapter 6.2. --- Learning logic programs --- p.148Chapter 6.2.1. --- Learning logic programs using LOGENPRO --- p.148Chapter 6.2.2. --- The Winston's arch problem --- p.151Chapter 6.2.3. --- The modified Quinlan's network reachability problem --- p.153Chapter 6.2.4. --- The factorial problem --- p.154Chapter 6.2.5. --- Discussion --- p.155Chapter 6.3. --- Learning programs in C --- p.155Chapter Chapter 7 : --- Knowledge Discovery in Databases --- p.159Chapter 7.1. --- Inducing decision trees using LOGENPRO --- p.160Chapter 7.1.1. --- Decision trees --- p.160Chapter 7.1.2. --- Representing decision trees as S-expressions --- p.164Chapter 7.1.3. --- The credit screening problem --- p.166Chapter 7.1.4. --- The experiment --- p.168Chapter 7.2. --- Learning logic program from imperfect data --- p.174Chapter 7.2.1. --- The chess endgame problem --- p.177Chapter 7.2.2. --- The setup of experiments --- p.178Chapter 7.2.3. --- Comparison of LOGENPRO with FOIL --- p.180Chapter 7.2.4. --- Comparison of LOGENPRO with BEAM-FOIL --- p.182Chapter 7.2.5. --- Comparison of LOGENPRO with mFOILl --- p.183Chapter 7.2.6. --- Comparison of LOGENPRO with mFOIL2 --- p.184Chapter 7.2.7. --- Comparison of LOGENPRO with mFOIL3 --- p.185Chapter 7.2.8. --- Comparison of LOGENPRO with mFOIL4 --- p.186Chapter 7.2.9. --- Comparison of LOGENPRO with mFOIL5 --- p.187Chapter 7.2.10. --- Discussion --- p.188Chapter 7.3. --- Learning programs in Fuzzy Prolog --- p.189Chapter Chapter 8 : --- An Adaptive Inductive Logic Programming System --- p.192Chapter 8.1. --- Adaptive Inductive Logic Programming --- p.192Chapter 8.2. --- A generic top-down ILP algorithm --- p.196Chapter 8.3. --- Inducing procedural search biases --- p.200Chapter 8.3.1. --- The evolution process --- p.201Chapter 8.3.2. --- The experimentation setup --- p.202Chapter 8.3.3. --- Fitness calculation --- p.203Chapter 8.4. --- Experimentation and evaluations --- p.204Chapter 8.4.1. --- The member predicate --- p.205Chapter 8.4.2. --- The member predicate in a noisy environment --- p.205Chapter 8.4.3. --- The multiply predicate --- p.206Chapter 8.4.4. --- The uncle predicate --- p.207Chapter 8.5. --- Discussion --- p.208Chapter Chapter 9 : --- Conclusion and Future Work --- p.210Chapter 9.1. --- Conclusion --- p.210Chapter 9.2. --- Future work --- p.217Chapter 9.2.1. --- Applying LOGENPRO to discover knowledge from databases --- p.217Chapter 9.2.2. --- Learning recursive programs --- p.218Chapter 9.2.3. --- Applying LOGENPRO in engineering design --- p.220Chapter 9.2.4. --- Exploiting parallelism of evolutionary algorithms --- p.222Reference --- p.227Appendix A --- p.23

Hybrid approaches for mobile robot navigation

The work described in this thesis contributes to the efficient solution of mobile robot navigation problems. A series of new evolutionary approaches is presented. Two novel evolutionary planners have been developed that reduce the computational overhead in generating plans of mobile robot movements. In comparison with the best-performing evolutionary scheme reported in the literature, the first of the planners significantly reduces the plan calculation time in static environments. The second planner was able to generate avoidance strategies in response to unexpected events arising from the presence of moving obstacles. To overcome limitations in responsiveness and the unrealistic assumptions regarding a priori knowledge that are inherent in planner-based and a vigation systems, subsequent work concentrated on hybrid approaches. These included a reactive component to identify rapidly and autonomously environmental features that were represented by a small number of critical waypoints. Not only is memory usage dramatically reduced by such a simplified representation, but also the calculation time to determine new plans is significantly reduced. Further significant enhancements of this work were firstly, dynamic avoidance to limit the likelihood of potential collisions with moving obstacles and secondly, exploration to identify statistically the dynamic characteristics of the environment. Finally, by retaining more extensive environmental knowledge gained during previous navigation activities, the capability of the hybrid navigation system was enhanced to allow planning to be performed for any start point and goal point

A fonética e fonologia da harmonia de [ATR] no português brasileiro

Orientadores: Maria Bernadete Marques Abaurre, Silke HamannTese (doutorado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem e University of AmsterdamResumo: Este trabalho apresenta uma análise das vogais pretônicas alvos de harmonia vocálica no português brasileiro. A partir da análise dos dialetos Gaúcho e Baiano, o trabalho descreve acusticamente as vogais pretônicas e tônicas envolvidas no processo de harmonia. O interesse pelo tema decorre da limitada abordagem fonético-acústica do fenômeno na literatura da área, sobretudo para investigar o papel de vogais baixas no gatilho da harmonia, assim como o papel das consoantes adjacentes. O trabalho aprofunda a observação de harmonia com vogais baixas constatada por Abaurre-Gnerre (1981), fenômeno defendido como um processo de harmonia governado pelo traço [ATR]. Para isso, desenvolveu-se um experimento que contou com a participação de seis sujeitos (3 homens e 3 mulheres) de cada dialeto. A análise fonético-acústica das vogais partiu das medidas do primeiro e segundo formantes (F1 e F2) das vogais acentuadas e das pretônicas. A partir da descrição acústica das vogais do português brasileiro, investigou-se em específico o comportamento das vogais pretônicas /e/ e /o/, alvos do processo de harmonia,constatando-se experimentalmente que a influência coarticulatória principal advém das vogais tônicas baixas /?, a, ?/ que agem como gatilho da harmonização. Partindo-se, então, dos resultados experimentais, o trabalho desenvolve uma metodologia chamada de Vowel Threshold baseada nas medidas dos parâmetros acústicos F1 e F2. Vowel Threshold tem como objetivo estimar limiares de categorias vocálicas no espaço acústico e desta forma mapear os movimentos de alçamento e abaixamento, anteriorização e posteriorização na produção de uma vogal. Esse método reduz os valores de F1 e F2 a uma escala que tem como ponto de referência o valor zero, que seria considerado o valor esperado para o token de uma vogal se não houvesse vieses introduzidos pela coarticulação V-V, pelas consoantes intervenientes ou outro processo relacionado à fala. Com essa medida, estipula-se um valor crítico que determina se uma vogal sofreu movimentos intra ou inter categoria. Os resultados da análise das medidas de Vowel Threshold evidenciaram que as vogais /e, o/ de todos os sujeitos não tendem ao alçamento para [i, u], mas são abaixadas para [?, ?] pelos falantes tanto do dialeto Gaucho quando do dialeto Baiano, embora haja variação intra e inter-falantes. Os resultados experimentais evidenciam ainda: (1) consoantes precedentes não possuem efeito de abaixamento ou de alçamento nas vogais /e, o/; (2) as consoantes soantes intervenientes são transparentes ao abaixamento nos dois dialetos, enquanto as obstruintes parecem ser opacas no dialeto Gaucho; (3) há um processo dissimilátorio no dialeto Baiano que não se configura como desarmonia, mas indica uma tendência a abaixamento intra-categoria, motivado pelo desarmonia de posterioridade entre o alvo e o gatilho. O trabalho ainda apresenta uma re-análise dos corpora de Bisol (1981) e Barbosa da Silva (1989) de modo a verificar o processo de harmonia de [+alto] constatado por essas autoras para discutir a supremacia da harmonia de altura no português brasileiro, contrastando com os resultados experimentais encontrados. Por fim, o trabalho evidencia que a harmonia de [ATR] parece ser o processo ativo do português brasileiro; e como evidência para isso, são trazidos argumentos da interação fonologia-morfologia, da contrastividade de vogais, da atribuição do acento secundário e do enviesamento introduzido pela ortografia nas análises do processo harmonia vocálica. Argumenta-se também que há um bloqueio da harmonia de [+alto] cuja motivação parece estar nas presença das oclusivas coronais /t, d/ precedentes às vogais-alvo. Traz-se evidência da literatura de que a harmonia de [+alto] é evitada por linguísticas, mas também sociolinguísticas, com resultados indicando um uso decrescente da harmonia de altura considerandos-se a idade e a escolaridade dos falantesAbstract: This study analyzes pre-stressed vowels that undergo vowel harmony in Brazilian Portuguese. Based on the analysis of the Gaucho and Baiano dialects, this work provides an acoustic description of pre-stressed and stressed vowels involved in vowel harmony. This subject is relevant because of the limited amount of acoustic-phonetic studies of this phenomenon in the literature, particularly of the role of low vowels in triggering vowel harmony, as well as the role of adjacent consonants. This study investigates the harmony patterns found by Abaurre-Gnerre (1981), a phenomenon which is hypothesized in this research as a process of harmony governed by the feature [ATR]. For this purpose, we developed a reading experiment with six participants (3 men and 3 women) from each dialect. The acoustic-phonetic analysis of the vowels was based on the measurements of the first and second formants (F1 and F2) of the pre-vowel and stressed vowels. From the acoustic description of the whole set of Brazilian Portuguese vowels, we found that the pre-stressed vowel harmony targets /e/ and /o/ are affected primarily by the low vowels /?, a, ?/, which can be considered the triggers. From the experimental results, we developed a method called Vowel Threshold, which is based on measurements of F1 and F2 to estimate thresholds of vowel categories in the acoustic space and therefore map the movements of raising, lowering, vowel-fronting and vowel-backing in vowel production. This method reduces the values of F1 and F2 to a scale that has zero as the reference point, which would be considered the expected value for the token of a vowel if there were no biases introduced by the V-to-V coarticulation, by the intervening consonants or other process related to speech. With this measurement, a critical value is stipulated to determine whether a vowel has undergone intra-category or inter-category movements. The results of the analysis of the Vowel Threshold measurements showed that the vowels /e, o/ of all subjects do not tend to be raised to [i, u], rather they are lowered to [?, ?] by speakers of both the Gaucho and Baiano dialects. Moreover, the experimental results show that: (1) the preceding consonants have no effect of lowering or raising in the vowels /e, o/; (2) the intervening sounding consonants are transparent to the lowering in the two dialects, while the obstruents appear to be opaque in the Gaucho dialect; (3) there is a dissimilatory process in Baiano that does not seem to be a disharmony, but indicates a tendency for intra-category lowering, motivated by the disagreement in [back] of the target and the trigger. The work also presents a re-analysis of the Bisol (1981) and Barbosa da Silva (1989) corpora in order to examine the process of [+high] harmony verified by those authors to discuss the supremacy of this sort of harmony in Brazilian Portuguese in contrast with the experimental results found in this work. Finally, this study shows that the BP [ATR] harmony seems to be the active harmony in Brazilian Portuguese; and as evidence for this, arguments from phonology-morphology interaction, vowel contrastiveness, secondary stress assignment, and orthography biasing in the analysis of vowel harmony are brought into the discussion. It is argued that there is a consonantal blocking effect of [+high] harmony motivated by certain preceding consonants to the target vowels. Evidence of [+high] harmony avoidance is also found in the sociolinguistic literature that shows a decreasing application of such harmonization according to the age and education of the speakersDoutoradoLinguisticaDoutor em Linguística140280/2012-06344/13-5CNPQCAPE

Modelling evolving clinical practice guidelines: a case of Malawi

Electronic medical record (EMR) systems are increasingly being adopted in low- and middle-income countries. This provides an opportunity to support task-shifted health workers with guideline-based clinical decision support to improve the quality of healthcare delivery. However, the formalization of clinical practice guidelines (CPGs) into computer-interpretable guidelines (CIGs) for clinical decision support in such a setting is a very challenging task due to the evolving nature of CPGs and limited healthcare budgets. This study proposed that a CIG modelling language that considers CPG change requirements in their representation models could enable semi-automated support of CPG change operations thereby reducing the burden of maintaining CIGs. Characteristics of CPG changes were investigated to elucidate CPG change requirements using CPG documents from Malawi where EMR systems are routinely used. Thereafter, a model-driven engineering approach was taken to design a CIG modelling framework that has a novel domain-specific modelling language called FCIG for the modelling of evolving CIGs. The CIG modelling framework was implemented using the Xtext framework. The national antiretroviral therapy EMR system for Malawi was extended into a prototype with FCIG support for experimentation. Further studies were conducted with CIG modellers. The evaluations were conducted to answer the following research questions: i) What are the CPG change requirements for modelling an evolving CIG? ii) Can a model-driven engineering approach adequately support the modelling of an evolving CIG? iii) What is the effect of modelling an evolving CIG using FCIG in comparison with the Health Level Seven (HL7) standard for modelling CIGs? Data was collected using questionnaires, logs and observations. The results indicated that finegrained components of a CPG are affected by CPG changes and that those components are not included explicitly in current executable CIG language models. The results also showed that by including explicit semantics for elements that are affected by CPG changes in a language model, smart-editing features for supporting CPG change operations can be enabled in a language-aware code editor. The results further showed that both experienced and CIG modellers perceived FCIG as highly usable. Furthermore, the results suggested that FCIG performs significantly better at CIG modelling tasks as compared to the HL7 standard, Arden Syntax. This study provides empirical evidence that a model-driven engineering approach to clinical guideline formalization supports the authoring and maintenance of evolving CIGs to provide up-to-date clinical decision support in low- and middle-income countries

Active fuzzing for testing and securing cyber-physical systems

National Research Foundation (NRF) Singapore under its National Satellite of Excellence Programm

Complex event types for agent-based simulation

This thesis presents a novel formal modelling language, complex event types (CETs), to describe behaviours in agent-based simulations. CETs are able to describe behaviours at any computationally represented level of abstraction. Behaviours can be specified both in terms of the state transition rules of the agent-based model that generate them and in terms of the state transition structures themselves. Based on CETs, novel computational statistical methods are introduced which allow statistical dependencies between behaviours at different levels to be established. Different dependencies formalise different probabilistic causal relations and Complex Systems constructs such as ‘emergence’ and ‘autopoiesis’. Explicit links are also made between the different types of CET inter-dependency and the theoretical assumptions they represent. With the novel computational statistical methods, three categories of model can be validated and discovered: (i) inter-level models, which define probabilistic dependencies between behaviours at different levels; (ii) multi-level models, which define the set of simulations for which an inter-level model holds; (iii) inferred predictive models, which define latent relationships between behaviours at different levels. The CET modelling language and computational statistical methods are then applied to a novel agent-based model of Colonic Cancer to demonstrate their applicability to Complex Systems sciences such as Systems Biology. This proof of principle model provides a framework for further development of a detailed integrative model of the system, which can progressively incorporate biological data from different levels and scales as these become available