Inductive Logic Programming in Databases: from Datalog to DL+log

In this paper we address an issue that has been brought to the attention of the database community with the advent of the Semantic Web, i.e. the issue of how ontologies (and semantics conveyed by them) can help solving typical database problems, through a better understanding of KR aspects related to databases. In particular, we investigate this issue from the ILP perspective by considering two database problems, (i) the definition of views and (ii) the definition of constraints, for a database whose schema is represented also by means of an ontology. Both can be reformulated as ILP problems and can benefit from the expressive and deductive power of the KR framework DL+log. We illustrate the application scenarios by means of examples. Keywords: Inductive Logic Programming, Relational Databases, Ontologies, Description Logics, Hybrid Knowledge Representation and Reasoning Systems. Note: To appear in Theory and Practice of Logic Programming (TPLP).Comment: 30 pages, 3 figures, 2 tables

Building Rules on Top of Ontologies for the Semantic Web with Inductive Logic Programming

Building rules on top of ontologies is the ultimate goal of the logical layer of the Semantic Web. To this aim an ad-hoc mark-up language for this layer is currently under discussion. It is intended to follow the tradition of hybrid knowledge representation and reasoning systems such as $\mathcal{AL}$-log that integrates the description logic $\mathcal{ALC}$ and the function-free Horn clausal language \textsc{Datalog}. In this paper we consider the problem of automating the acquisition of these rules for the Semantic Web. We propose a general framework for rule induction that adopts the methodological apparatus of Inductive Logic Programming and relies on the expressive and deductive power of $\mathcal{AL}$-log. The framework is valid whatever the scope of induction (description vs. prediction) is. Yet, for illustrative purposes, we also discuss an instantiation of the framework which aims at description and turns out to be useful in Ontology Refinement. Keywords: Inductive Logic Programming, Hybrid Knowledge Representation and Reasoning Systems, Ontologies, Semantic Web. Note: To appear in Theory and Practice of Logic Programming (TPLP)Comment: 30 pages, 6 figure

A Semantic Similarity Measure for Expressive Description Logics

A totally semantic measure is presented which is able to calculate a similarity value between concept descriptions and also between concept description and individual or between individuals expressed in an expressive description logic. It is applicable on symbolic descriptions although it uses a numeric approach for the calculus. Considering that Description Logics stand as the theoretic framework for the ontological knowledge representation and reasoning, the proposed measure can be effectively used for agglomerative and divisional clustering task applied to the semantic web domain.Comment: 13 pages, Appeared at CILC 2005, Convegno Italiano di Logica Computazionale also available at http://www.disp.uniroma2.it/CILC2005/downloads/papers/15.dAmato_CILC05.pd

Abstractive Opinion Tagging

In e-commerce, opinion tags refer to a ranked list of tags provided by the e-commerce platform that reflect characteristics of reviews of an item. To assist consumers to quickly grasp a large number of reviews about an item, opinion tags are increasingly being applied by e-commerce platforms. Current mechanisms for generating opinion tags rely on either manual labelling or heuristic methods, which is time-consuming and ineffective. In this paper, we propose the abstractive opinion tagging task, where systems have to automatically generate a ranked list of opinion tags that are based on, but need not occur in, a given set of user-generated reviews. The abstractive opinion tagging task comes with three main challenges: (1) the noisy nature of reviews; (2) the formal nature of opinion tags vs. the colloquial language usage in reviews; and (3) the need to distinguish between different items with very similar aspects. To address these challenges, we propose an abstractive opinion tagging framework, named AOT-Net, to generate a ranked list of opinion tags given a large number of reviews. First, a sentence-level salience estimation component estimates each review's salience score. Next, a review clustering and ranking component ranks reviews in two steps: first, reviews are grouped into clusters and ranked by cluster size; then, reviews within each cluster are ranked by their distance to the cluster center. Finally, given the ranked reviews, a rank-aware opinion tagging component incorporates an alignment feature and alignment loss to generate a ranked list of opinion tags. To facilitate the study of this task, we create and release a large-scale dataset, called eComTag, crawled from real-world e-commerce websites. Extensive experiments conducted on the eComTag dataset verify the effectiveness of the proposed AOT-Net in terms of various evaluation metrics.Comment: Accepted by WSDM 202

Infinite Author Topic Model based on Mixed Gamma-Negative Binomial Process.

Incorporating the side information of text corpus, i.e., authors, time stamps, and emotional tags, into the traditional text mining models has gained significant interests in the area of information retrieval, statistical natural language processing, and machine learning. One branch of these works is the so-called Author Topic Model (ATM), which incorporates the authors's interests as side information into the classical topic model. However, the existing ATM needs to predefine the number of topics, which is difficult and inappropriate in many real-world settings. In this paper, we propose an Infinite Author Topic (IAT) model to resolve this issue. Instead of assigning a discrete probability on fixed number of topics, we use a stochastic process to determine the number of topics from the data itself. To be specific, we extend a gamma-negative binomial process to three levels in order to capture the author-document-keyword hierarchical structure. Furthermore, each document is assigned a mixed gamma process that accounts for the multi-author's contribution towards this document. An efficient Gibbs sampling inference algorithm with each conditional distribution being closed-form is developed for the IAT model. Experiments on several real-world datasets show the capabilities of our IAT model to learn the hidden topics, authors' interests on these topics and the number of topics simultaneously.Comment: 10 pages, 5 figures, submitted to KDD conferenc

Assessing the impact of a cloud-based learning platform on student motivation and ownership of learning

Has the KuraCloud learning platform increased student motivation and ownership of their learning? Cloud-based educational technologies are used with the expectation that they will assist students to become life-long learners. These technologies give students more control over their learning and this has been shown to motivate them to work harder (Yurco, 2014). This research examines the impact of a recently implemented cloud-based learning platform (KuraCloud) on student motivation and ownership of their learning. All students enrolled in the undergraduate Bachelor of Nursing programme at Wintec will be invited to participate in an online survey. Areas that will be explored to assess motivation include whether students feel more motivated, whether they feel encouraged to seek extra information about topics, and whether their participation is influenced by particular aspects and exercises within the KuraCloud lessons. Areas that will be explored to assess ownership of learning include whether the KuraCloud lessons helped them to learn independently, to problem-solve, and to understand the topic content and the lesson concepts. The research has not been completed yet, but the results will be presented at the conference. It is expected that the results will inform future planning to enhance student motivation and ownership of learning using this technology

High frequency jet ventilation (HFJV) in clinical practice

Background: Surgery often requires general anaesthesia. During general anaesthesia, a ventilator is often used to secure the breathing of the patient. This is preferably done by mimicking normal ventilation. Conventional ventilation causes the lung to inflate and deflate which in turn makes the diaphragm move up and down in the craniocaudal direction. Therefore, all organs adjacent to the diaphragm will be affected by these breathing-related motions. During liver tumour ablation, stereotactic technique can be used. During stereotactic technique, radiological images are used to optimise needle placement in three dimensions, to reach the target tumour. It is of great importance that the target tumour does not move, ensuring that the tissue destruction is limited to the tumour and avoiding injury of healthy surrounding tissue. To meet the demand of target organ immobilisation, high frequency jet ventilation (HFJV) has become an interesting option. This method uses small tidal volumes at high frequencies that highly differ from normal physiological respiration in humans, contrary to conventional ventilation during surgery. HFJV has been used for decades especially for ventilation during airway procedures. To ventilate the patient while minimising abdominal organ movement and thereby improving surgical conditions during stereotactic ablative procedures is a novel way of using the benefits of HFJV. Aim: This doctoral thesis studied the feasibility and safety of using high frequency jet ventilation for the specific purpose of liver immobilisation during stereotactic ablation procedures. The aim of Study I was to study gas exchange during HFJV during stereotactic ablation of liver tumours. In Study II, post-operative hypertension and its relation to liver tumour ablation techniques and ventilation methods were studied. In Study III the formation of atelectasis during HFJV was studied. In Study IV the levels of carbon dioxide (CO2) were studied in two different groups randomised to different sizes of the endotracheal tube in which the jet-catheter was placed during HFJV in liver tumour ablation. In Study IV continuous transcutaneous carbon dioxide (TcCO2) monitoring was compared to intermittent measurement of arterial carbon dioxide (PaCO2). Methods: Study I is a prospective, observational study. Blood gas analysis was performed every 15 minutes for the first 45 minutes of HFJV in 24 patients undergoing liver tumour ablation. Study II is a retrospective, observational study. Medical chart records were collected and analysed for early post-operative hypertension for 134 patients receiving either HFJV or conventional ventilation (CV) and various ablation methods, microwave ablation (MWA) or irreversible electroporation (IRE). Study III is a prospective, observational study. CT-images over the lower part of the lung were taken in 25 patients every 15 minutes during the first 45 minutes of HFJV. The images were analysed for atelectasis formation during HFJV using the MatLab software program. Study IV is a randomised, prospective study. PaCO2 was measured during the first 45 minutes after initiation of HFJV in patients randomised to endotracheal tube (ETT) inner diameter (ID) 8 or 9 mm. TcCO2 was also measured during the same period and compared to gold standard PaCO2. Airway pause pressures, peak pressures and signs of intubation injuries were also studied. Results: In Study I blood gas analyses showed that none of the 24 patients experienced hypoxemia during the first 45 minutes of high frequency jet ventilation. A statistically significant rise in arterial carbon dioxide (PaCO2) was seen at all time points during HFJV compared to baseline. A further statistically significant rise in PaCO2 was seen during HFJV compared to T=0 at T=30 (p=0.006) and T=45 (p=0.003). A corresponding statistically significant decrease in pH was seen compared to baseline at T=15 (p=0.03) from a mean value of 7.44 to 7.31. A further small drop in pH was seen over time but with no significance between time points. During early recovery in the post anaesthesia care unit, PaCO2 and pH resumed spontaneous to baseline values. All lactate values were within normal range except for one value in one patient during recovery that was slightly raised to 2.3 mmol L-1. Study II showed that hypertension was common in post-operative care after liver tumour ablation. Patients receiving MWA under HFJV had the highest proportion of having at least one episode of severe hypertension (SAP >180 mmHg) when compared to patients receiving IRE under HFJV and MWA under CV. Multiple regression analysis showed increased odds for post-operative hypertension when MWA was used compared to IRE and when HFJV was used compared to CV. Study III showed that the formation of atelectasis increased over time during HFJV during the 45 minutes studied, from 5.6% to 8.1% of the total lung area. The increase in atelectasis was significant at T=30 (p=0.002) and T=45 (p=0.024). The area of normal ventilation was however unchanged. In a subgroup analysis with patients with a BMI<30, no significant difference in the amount of atelectasis could be seen between the time points. In Study IV PaCO2 increased in both groups, with ETT ID 8 and 9 mm, but no statistically significant difference between the two groups was seen (p=0.06). TcCO2 was measured and compared to PaCO2. A Bland-Altman plot and an ICC analysis showed a good correlation between the two methods. Conclusions: The overall result of this thesis indicates that high frequency jet ventilation is feasible and safe during stereotactic ablation of upper abdominal organs for up to 45 minutes. There is a risk of hypertensive events in the early recovery, following liver tumour ablation when MWA and HFJV are used. Atelectasis increases but the proportion of normally ventilated lung is preserved. PaCO2 increases but is rapidly reversed during recovery. An ETT ID 8 mm can be used in male patients for shorter procedures, regarding PaCO2. TcCO2 is a feasible technique when following the changes in carbon dioxide although blood gas analysis should be considered in patients in need for haemodynamic monitoring and risk of carbon dioxide retention