Temporalised Description Logics for Monitoring Partially Observable Events

Inevitably, it becomes more and more important to verify that the systems surrounding us have certain properties. This is indeed unavoidable for safety-critical systems such as power plants and intensive-care units. We refer to the term system in a broad sense: it may be man-made (e.g. a computer system) or natural (e.g. a patient in an intensive-care unit). Whereas in Model Checking it is assumed that one has complete knowledge about the functioning of the system, we consider an open-world scenario and assume that we can only observe the behaviour of the actual running system by sensors. Such an abstract sensor could sense e.g. the blood pressure of a patient or the air traffic observed by radar. Then the observed data are preprocessed appropriately and stored in a fact base. Based on the data available in the fact base, situation-awareness tools are supposed to help the user to detect certain situations that require intervention by an expert. Such situations could be that the heart-rate of a patient is rather high while the blood pressure is low, or that a collision of two aeroplanes is about to happen. Moreover, the information in the fact base can be used by monitors to verify that the system has certain properties. It is not realistic, however, to assume that the sensors always yield a complete description of the current state of the observed system. Thus, it makes sense to assume that information that is not present in the fact base is unknown rather than false. Moreover, very often one has some knowledge about the functioning of the system. This background knowledge can be used to draw conclusions about the possible future behaviour of the system. Employing description logics (DLs) is one way to deal with these requirements. In this thesis, we tackle the sketched problem in three different contexts: (i) runtime verification using a temporalised DL, (ii) temporalised query entailment, and (iii) verification in DL-based action formalisms

Action, Time and Space in Description Logics

Description Logics (DLs) are a family of logic-based knowledge representation (KR) formalisms designed to represent and reason about static conceptual knowledge in a semantically well-understood way. On the other hand, standard action formalisms are KR formalisms based on classical logic designed to model and reason about dynamic systems. The largest part of the present work is dedicated to integrating DLs with action formalisms, with the main goal of obtaining decidable action formalisms with an expressiveness significantly beyond propositional. To this end, we offer DL-tailored solutions to the frame and ramification problem. One of the main technical results is that standard reasoning problems about actions (executability and projection), as well as the plan existence problem are decidable if one restricts the logic for describing action pre- and post-conditions and the state of the world to decidable Description Logics. A smaller part of the work is related to decidable extensions of Description Logics with concrete datatypes, most importantly with those allowing to refer to the notions of space and time

Computing Updates in Description Logics

Description Logics (DLs) form a family of knowledge representation formalisms which can be used to represent and reason with conceptual knowledge about a domain of interest. The knowledge represented by DLs is mainly static. In many applications, the domain knowledge is dynamic. This observation motivates the research on how to update the knowledge when changes in the application domain take place. This thesis is dedicated to the study of updating knowledge, more precisely, assertional knowledge represented in DLs. We explore whether the updated knowledge can be expressed in several standard DLs and, if so, whether it is computable and what is its size

Reclaiming Sacred Homelands: Asserting Treaty Rights and the Path Towards Restoration of the Badger-Two Medicine

“In order for law to have an influence in the lives of ordinary people, it must have something to do with the emotional feelings of justice, it must speak to our basic humanity, and it must give us common sense directions as to what behavior and beliefs are right and wron

Elinkaaritiedon hallinta tuotetietomallissa

In modern, global manufacturing business, value is increasingly created by services related to products rather than the products themselves. In industries related to the built environment, various products installed in the buildings are a major asset for the operators and managers of buildings. Product Lifecycle Management (PLM), managing and exploiting product-related information throughout the lifecycle of the product, has become both a requirement and an important tool for effective service business development. Extensive and interactive PLM requires a universal system for information exchange across the lifecycles of buildings and products. The objective of the study is to define and implement the minimum requirements set by a product-centric information exchange system in an IFC-based product information model, based on use case of managing installed medical equipment in hospital environment. The study comprises a literature analysis and a use case. Late literature was reviewed to analyse developments of intelligence and lifecycle management in products and buildings. It was found that major challenges exist in exchanging lifecycle information between stakeholders and across lifecycle stages. Based on the analysis, it is proposed that using the technologies of building information modelling and a product-centric information exchange system could provide novel solutions to the identified challenges. In the use case, a method was developed for incorporating an open, product-centric PLM information exchange system into the existing IFC standard. It was found that an URI-based, product-centric information exchange system using external databases and product servers satisfies the requirements of effective PLM information exchange. Additionally, it was found that using IFC for product information modelling can effectively support such a system by linking virtual building and product information models into the lifecycle information stored in external servers.Nykyaikaisessa, kansainvälisessä valmistavan teollisuuden liiketoiminnassa arvoa luodaan entistä enemmän tuotteisiin liittyvillä palveluilla kuin itse tuotteilla. Rakennettuun ympäristöön liittyvässä liiketoiminnassa rakennuksiin asennetut tuotteet muodostavat suuren pääoman rakennusten käyttäjille ja hallinnoijille. Tuotteiden elinkaaren hallinta (Product Lifecycle Management, PLM), eli tuotteisiin liittyvän tiedon hallinta ja hyödyntäminen tuotteen elinkaaren aikana, on muodostunut sekä vaatimukseksi että tärkeäksi työkaluksi tehokkaiden liiketoiminnallisten palvelujen kehittämisessä. Laaja-alainen ja vuorovaikutteinen PLM edellyttää yleismaailmallista tiedonvaihtojärjestelmää rakennusten ja tuotteiden elinkaarten varrelle. Työn tavoitteena on määritellä ja toteuttaa tuotekeskeisen tiedonvaihtojärjestelmän asettamat vähimmäisvaatimukset IFC-pohjaiseen tuotetietomalliin käyttötapauksessa (use case), jossa kiinteästi asennettavia lääkinnällisiä laitteita hallitaan sairaalaympäristössä. Työ koostuu kirjallisuustutkimuksesta ja käyttötapauksesta. Tuotteiden ja rakennusten elinkaaren hallinnan ja älyn kehitystä analysoitiin kirjallisuuslähteiden perusteella. Elinkaaren aikaisen tiedon vaihtamisessa osapuolten ja elinkaaren vaiheiden välillä havaittiin merkittäviä haasteita. Analyysin perusteella työssä esitetään, että tietomallintamisen teknologioiden ja tuotekeskeisen tiedonvaihtojärjestelmän käyttäminen voivat tarjota uusia ratkaisuja tunnistettuihin haasteisiin. Käyttötapauksessa kehitettiin menetelmä avoimen, tuotekeskeisen PLM-tiedonvaihtojärjestelmän yhdistämiseksi nykyiseen IFC-standardiin. Työssä havaittiin, että URI:in perustuva, ulkoisia tietokantoja ja tuotepalvelimia hyödyntävä tuotekeskeinen tiedonvaihtojärjestelmä täyttää tehokkaan PLM-tiedonvaihdon vaatimukset. Lisäksi havaittiin, että tuotteiden tietomallintaminen IFC:ia käyttämällä tukee järjestelmää tehokkaasti linkittämällä virtuaaliset rakennus- ja tuotetietomallit ulkoisilla palvelimilla sijaitsevaan elinkaaritietoon

A survey on independence-based Markov networks learning

This work reports the most relevant technical aspects in the problem of learning the \emph{Markov network structure} from data. Such problem has become increasingly important in machine learning, and many other application fields of machine learning. Markov networks, together with Bayesian networks, are probabilistic graphical models, a widely used formalism for handling probability distributions in intelligent systems. Learning graphical models from data have been extensively applied for the case of Bayesian networks, but for Markov networks learning it is not tractable in practice. However, this situation is changing with time, given the exponential growth of computers capacity, the plethora of available digital data, and the researching on new learning technologies. This work stresses on a technology called independence-based learning, which allows the learning of the independence structure of those networks from data in an efficient and sound manner, whenever the dataset is sufficiently large, and data is a representative sampling of the target distribution. In the analysis of such technology, this work surveys the current state-of-the-art algorithms for learning Markov networks structure, discussing its current limitations, and proposing a series of open problems where future works may produce some advances in the area in terms of quality and efficiency. The paper concludes by opening a discussion about how to develop a general formalism for improving the quality of the structures learned, when data is scarce.Comment: 35 pages, 1 figur