Explanation-based learning with analogy for impasse resolution

This paper proposes an algorithm for the inclusion of analogy into Explanation-Based Learning (EBL). Analogy can be used when an impasse is reached to extend the deductive closure of EBL’s domain theory. This enables the generation of control laws, via EBL, for hardware which is not catered for in the domain theory. This advantage addresses a problem which represents a dearth in the current literature. Integrated Modular Avionics (IMA) literature has thus far been concerned with the architectural considerations. This paper seeks to address the impact of hardware changes on the controllers within an IMA architecture. An algorithm is proposed and applied to control an aviation platform with an incomplete domain theory. Control rules are generated when no deductive explanations are possible, which still reflect the intent of the domain theory

Adaptive Safety Arguments and Explanation-Based Learning

Abstract. Software for use in aviation requires certification. This certification is based on a safety argument. These arguments are formed of claims that are linked to evidence about the system. Adaptive systems are a grey area within the current certification guidelines (DO-178 document). Safety cases (sometimes called safety arguments) link claims and evidence in support of an overall safety argument. This paper argues that it is rational to have an adaptive safety argument for an adaptive system. This is illustrated by considering an adaptive controller that uses Explanation-Based Learning (EBL) to generate both control laws and a safety argument, represented using Goal-Structuring Notation. An adaptive safety argument, when coupled with analytical tools, could be used to form the adaptive portion of an otherwise standards-based certification argument. If the rest of the argument holds then the argument should hold for any state where the adaptive safety cases remain valid.

Supporting the corpus-based study of Shakespeare’s language:Enhancing a corpus of the First Folio

This article explores challenges in the corpus linguistic analysis of Shakes-peare’s language, and Early Modern English more generally, with particularfocus on elaborating possible solutions and the benefits they bring. An accountof work that took place within the Encyclopedia of Shakespeare’s LanguageProject (2016–2019) is given, which discusses the development of the project’sdata resources, specifically, the Enhanced Shakespearean Corpus. Topics cov-ered include the composition of the corpus and its subcomponents; the structureof the XML markup; the design of the extensive character metadata; and theword-level corpus annotation, including spelling regularisation, part-of-speechtagging, lemmatisation and semantic tagging. The challenges that arise fromeach of these undertakings are not exclusive to a corpus-based treatment ofShakespeare’s plays but it is in the context of Shakespeare’s language that theyare so severe as to seem almost insurmountable. The solutions developed for theEnhanced Shakespearean Corpus – often combining automated manipulationwith manual interventions, and always principled – offer a way through

Cement-in-cement revision of the femur in infected hip arthroplasty in 89 patients across two centres

Aims: Femoral cement-in-cement revision is a well described technique to reduce morbidity and complications in hip revision surgery. Traditional techniques for septic revision of hip arthroplasty necessitate removal of all bone cement from the femur. In our two centres, we have been using a cement-in-cement technique, leaving the distal femoral bone cement in selected patients for septic hip revision surgery, both for single and the first of two-stage revision procedures. A prerequisite for adoption of this technique is that the surgeon considers the cement mantle to be intimately fixed to bone without an intervening membrane between cement and host bone. We aim to report our experience for this technique. Methods: We have analyzed patients undergoing this cement-in- cement technique for femoral revision in infection, and present a consecutive series of 89 patients. Follow-up was undertaken at a mean of 56.5 months (24.0 to 134.7) for the surviving cases. Results: Seven patients (7.9%) required further revision for infection. Ten patients died of causes unrelated to their infection before their two-year review (mean 5.9 months; 0.9 to 18.6). One patient was lost to follow-up at five months after surgery, and two patients died of causes unrelated to their hip shortly after their two-year review was due without attending. Of the remaining patients, 69 remained infection-free at final review. Radiological review confirms the mechanical success of the procedure as previously described in aseptic revision, and postoperative Oxford Hip Scores suggest satisfactory functional outcomes. Conclusion: In conclusion, we found that retaining a well-fixed femoral cement mantle in the presence of infection and undertaking a cement-in-cement revision was successful in 82 of the patients (92.1%) in our series of 89, both in terms of eradication of infection and component fixation. These results are comparable to other more invasive techniques and offer significant potential benefits to the patient. </p