A beginner's guide to belief revision and truth maintenance systems

This brief note is intended to familiarize the non-TMS audience with some of the basic ideas surrounding classic TMS's (truth maintenance systems), namely the justification-based TMS and the assumption-based TMS. Topics of further interest include the relation between non-monotonic logics and TMS's, efficiency and search issues, complexity concerns, as well as the variety of TMS systems that have surfaced in the past decade or so. These include probabilistic-based TMS systems, fuzzy TMS systems, tri-valued belief systems, and so on

The 14th Overture Workshop: Towards Analytical Tool Chains

This report contains the proceedings from the 14th Overture workshop organized in connection with the Formal Methods 2016 symposium. This includes nine papers describing different technological progress in relation to the Overture/VDM tool support and its connection with other tools such as Crescendo, Symphony, INTO-CPS, TASTE and ViennaTalk

Using social semantic knowledge to improve annotations in personal photo collections

Instituto Politécnico de Lisboa (IPL) e Instituto Superior de Engenharia de Lisboa (ISEL)apoio concedido pela bolsa SPRH/PROTEC/67580/2010, que apoiou parcialmente este trabalh

A source modelling system and its use for uncertainty management

Human agents have to deal with a considerable amount of information from their environment and are also continuously faced with the need to take actions. As that information is largely of an uncertain nature, human agents have to decide whether, or how much, to believe individual pieces of information. To enable a reasoning system to deal in general with the demands of a real environment, and with information from human sources in particular, requires tools for uncertainty management and belief formation. This thesis presents a model for the management of uncertain information from human sources. Dealing, more specifically, with information which has been pre-processed by a natural language processor and transformed into an event-based representation, the model assesses information, forms beliefs and resolves conflicts between them in order to maintain a consistent world model. The approach is built on the fundamental principle that the uncertainty of information from people can, in the majority of situations, successfully be assessed through source models which record factors concerning the source's abilities and trustworthiness. These models are adjusted to reflect changes in the behaviour of the source. A mechanism is presented together with the underlying principles to reproduce such a behaviour. A high-level design is also given to make the proposed model reconstructible, and the successful operation of the model is demonstrated on two detailed examples

Linguistic alignment and theory of mind impairments in schizophrenia patients' dialogic interactions

BACKGROUND: Impairments of contextual processing and theory of mind (ToM) have both been offered as accounts of the deviant language characterising formal thought disorder (FTD) in schizophrenia. This study investigated these processes in patients' dialogue. We predicted that FTD patients would show a decrement in linguistic alignment, associated with impaired ToM in dialogue. METHODS: Speech samples were elicited via participation in an interactive computer-based task and a semi-structured interview to assess contextual processing abilities and ToM skills in dialogue, respectively, and from an interactive card-sorting task to measure syntactic alignment. Degree of alignment in dialogue and the syntactic task, and evidence of ToM in (i) dialogue and (ii) a traditional ToM task were compared across schizophrenia patients with FTD (n = 21), non-FTD patients (n = 22) and healthy controls (n = 21). RESULTS: FTD patients showed less alignment than the other two groups in dialogue, and than healthy controls on the syntactic task. FTD patients showed poorer performance on the ToM task than the other two groups, but only compared to the healthy controls in dialogue. The FTD group's degree of alignment in dialogue was correlated with ToM performance in dialogue but not with the traditional ToM task or with syntactic alignment. CONCLUSIONS: In dialogue, FTD patients demonstrate an impairment in employing available contextual information to facilitate their own subsequent production, which is associated with a ToM deficit. These findings indicate that a contextual processing deficit impacts on exploiting representations via the production system impoverishing the ability to make predictions about upcoming utterances in dialogue

A blackboard-based system for learning to identify images from feature data

A blackboard-based system which learns recognition rules for objects from a set of training examples, and then identifies and locates these objects in test images, is presented. The system is designed to use data from a feature matcher developed at R.S.R.E. Malvern which finds the best matches for a set of feature patterns in an image. The feature patterns are selected to correspond to typical object parts which occur with relatively consistent spatial relationships and are sufficient to distinguish the objects to be identified from one another. The learning element of the system develops two separate sets of rules, one to identify possible object instances and the other to attach probabilities to them. The search for possible object instances is exhaustive; its scale is not great enough for pruning to be necessary. Separate probabilities are established empirically for all combinations of features which could represent object instances. As accurate probabilities cannot be obtained from a set of preselected training examples, they are updated by feedback from the recognition process. The incorporation of rule induction and feedback into the blackboard system is achieved by treating the induced rules as data to be held on a secondary blackboard. The single recognition knowledge source effectively contains empty rules which this data can be slotted into, allowing it to be used to recognise any number of objects - there is no need to develop a separate knowledge source for each object. Additional object-specific background information to aid identification can be added by the user in the form of background checks to be carried out on candidate objects. The system has been tested using synthetic data, and successfully identified combinations of geometric shapes (squares, triangles etc.). Limited tests on photographs of vehicles travelling along a main road were also performed successfully

Spatialities of social justice: Reflections on South African cities.

The geographical engagement with social justice has neglected to adequately focus on the spatiality of the concept and its implications for geographical investigation. As a first response to this omission, this thesis illuminates the spatiality of social justice by suggesting that the concept is a historically and geographically located understanding of the manner in which society's benefits and burdens can be distributed. This thesis develops a route of geographical enquiry into the concept of social justice that moves beyond the tripartite of structuralist, post-structuralist and egalitarian approaches currently supported in this discipline. Drawing on relatively neglected liberal debates, the spatiality of social justice is investigated in relation to both theoretical and empirical accounts of this concept. It is subsequently suggested that Hayek's liberal challenge to the notion of unitary understandings of social justice, presents a productive alternative to current geographical investigations focused on this concept. Following Hayek's challenge, social justice is presented as a concept that is located, differentiated, bound to particular spatial arrangements and reflected through various imaginations of inclusion and exclusion. In this light a spatially sensitive account of social justice draws attention to the particularity of geography and history in shaping understandings of social justice. These themes are investigated within the concrete historical context of South African urban development. Here, the spatiality of social justice is explored with reference to the construction and demise of apartheid. This specific theme is then developed through a case study of the post-apartheid city of Tygerberg, the second largest local authority in the Cape Metropolitan Area. The investigation of Tygerberg illustrates that understandings of social justice are multiple, contested and located in particular understandings of the urban world at various stages of imagining the apartheid city. These differentiated understandings of social justice persist in the post-apartheid urban era, with notions of social justice shaped by the history and the geography of the apartheid realities from which it has arisen

Internet of Things-based Traffic Management System for Maseru, Lesotho.

Published ThesisThe number of vehicles in Maseru has been steadily increasing, leading to heightened intensity of congestion and traffic occurrences. This is further exacerbated by ineffective solutions that are currently in place as well as the absence of tools that facilitate dispersal of information to motorists. Traffic lights have been put in place to manage flow of traffic but are becoming increasingly inefficient due to their design. The preset timing cycles between green, amber and red disregarding prevailing conditions leads, inter alia, to increased wait times, use of additional fuel and air pollution. In addition, lack of equipment that is able to provide motorists with information about prevailing road conditions further increases the possibility of one being stuck in traffic. To make traffic management more efficient at signaled junctions, the implementation of the Internet of Things (IoT) paradigm is used to create intelligent traffic management systems such as Wireless Sensor Networks (WSN) and fuzzy algorithms to intelligently decide the phases of traffic lights. Road density and vehicles’ speeds are collected from the road infrastructure using cameras and are passed to a fuzzy algorithm to determine how congested a road is. Dependent on these parameters, the algorithm will also determine which roads should be given highest priority while maintaining a degree of fairness, thus optimizing traffic flow. In addition, the ubiquitous provision of road condition information to motorists in various formats such as text and audio is also used. This feature allows for the acquisition of the latest road status, thus making it possible to find alternative routes. The unique feature in this project is the ability to collect road parameters from the road infrastructure itself, using WSN as well as crowd source data from road users using mobile devices. A study conducted in this research revealed a relationship between the number of cars on a road and concentration of Carbon Dioxide (CO2); the results showed that as the number of cars increases, so does the measure of CO2. Questionnaire-based surveys showed that Maseru citizens have noted an increase in congestion which they attributed to the increase in number of vehicles on the road that is not met by the increase or improvement in road infrastructure. The respondents in this survey also noted limited mechanisms that provide them with road conditions and highlighted that such tools may alleviate congestion. The performance of intelligent traffic lights was conducted via simulations compared with fixed cycle traffic lights. From the simulations it was observed that IoT- based traffic management systems reduced the wait times of vehicles at signaled junctions which would also result in reduction of the pollutant CO2. It is envisaged that the future implementation will include the ability to manage a network of junctions and ability to predict abnormal traffic flows