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Many single-agent search algorithms have parameters that need to be tuned. Although settings found by offline tuning will exhibit strong average performance, properly selecting parameter settings for each problem can result in substantially reduced search effort. We consider the use of dovetailing as a way to deal with this issue. This procedure performs search with multiple parameter settings simultaneously. We present results testing the use of dovetailing with the weighted A*, weighted IDA*, weighted RBFS, and BULB algorithms on the sliding tile and pancake puzzle domains. Dovetailing will be shown to significantly improve weighted IDA*, often by several orders of magnitude, and generally enhance weighted RBFS. In the case of weighted A* and BULB, dovetailing will be shown to be an ineffective addition to these algorithms. A trivial parallelization of dovetailing will also be shown to decrease the search time in all considered domains.

In this thesis we extend BDI logics, which are normal multimodal logics with an arbitrary set of normal modal operators, from three different perspectives. Firstly, based on some recent developments in modal logic, we examine BDI logics from a combining logic perspective and apply combination techniques like fibring/dovetailing for explaining them. The second perspective is to extend the underlying logics so as to include action constructs in an explicit way based on some recent action-related theories. The third perspective is to adopt a non-monotonic logic like defeasible logic to reason about intentions in BDI. As such, the research captured in this thesis is theoretical in nature and situated at the crossroads of various disciplines relevant to Artificial Intelligence (AI). More specifically this thesis makes the following contributions: 1. Combining BDI Logics through fibring/dovetailing: BDI systems modeling rational agents have a combined system of logics of belief, time and intention which in turn are basically combinations of well understood modal logics. The idea behind combining logics is to develop general techniques that allow to produce combinations of existing and well understood logics. To this end we adopt Gabbay's fibring/dovetailing technique to provide a general framework for the combinations of BDI logics. We show that the existing BDI framework is a dovetailed system. Further we give conditions on the fibring function to accommodate interaction axioms of the type G [superscript k,l,m,n] ([diamond][superscript k] [superscript l] [phi] [implies] [superscript m] [diamond][superscript n] [phi]) based on Catach's multimodal semantics. This is a major result when compared with other combining techniques like fusion which fails to accommodate axioms of the above type. 2. Extending the BDI framework to accommodate Composite Actions: Taking motivation from a recent work on BDI theory, we incorporate the notion of composite actions, [pi]-1; [pi]-2 (interpreted as [pi]-1 followed by [pi]-2), to the existing BDI framework. To this end we introduce two new constructs Result and Opportunity which helps in reasoning about the actual execution of such actions. We give a set of axioms that can accommodate the new constructs and analyse the set of commitment axioms as given in the original work in the background of the new framework. 3. Intention reasoning as Defeasible reasoning: We argue for a non-monotonic logic of intention in BDI as opposed to the usual normal modal logic one. Our argument is based on Bratman's policy-based intention. We show that policy-based intention has a defeasible/non-monotonic nature and hence the traditional normal modal logic approach to reason about such intentions fails. We give a formalisation of policy-based intention in the background of defeasible logic. The problem of logical omniscience which usually accompanies normal modal logics is avoided to a great extend through such an approach.

Ökad användning av byggtekniken massivträ kan ge ett positivt bidrag till hållbart byggande. Utvecklingen inom datornavigerad bearbetning ger massivträ möjligheten att rationalisera byggproduktionen inom trä. Tekniken ligger rätt i tiden och kommer att värderas allt högre då den tillvaratar materialets karaktäristiska egenskaper. Utvecklingen av massivträ har resulterat i teknikvarianter av hur virke kan sammanfogas till solida element. Ett behov har funnits av en marknadsjämförelse mellan befintliga principer där studien förtydligar grundläggande skillnader för intresserade byggaktörer. Problemfrågan för denna studie har varit: vilka principer för sammanfogning av trä till plattelement inom massivträ är mest fördelaktiga? Detta sett utifrån faktorerna produktionskostnad, hållfasthet och ekologiska övervägningar. För att förtydliga den undersökta byggmetodens nytta i ett vidare perspektiv har det presenterats en allmän beskrivning av massivträ. Studien är jämförande och grundar sig på en litteraturstudie samt företagskontakter med 27 företag i 6 länder. Följande tekniker för tillverkning av plattelement i massivträ har behandlats i rapporten:  Limning  Spikning  Klamring  Skruvning  Tvärspänning  Dymling: vertikal-, horisontal- och diagonalgående samt med skruvar i trä  Laskning  Träsvetsning Studien visar att teknikerna inom massivträ skiljer sig åt. Högst bedömning får korslimmat trä (CLT) när det gäller kostnad och hållfasthet. Med hänsyn till ekologin värderas laskat trä högst. Vid en sammanvägning av hållfasthet och ekologi är den skruvformade trädymlingen fördelaktigast. Dessa alternativ ger valfrihet i synlig yta samt ett effektivt resursutnyttjande av lågvärdigare virkeskvalitéer och lämpar sig inom bostadsbyggnation. CLT är mest kostnadseffektivt, inte patentskyddat samt det mest etablerade alternativet på marknaden dock är utvecklingen av ett sunt lim fortfarande under arbete. I pågående forskning finns ett annat alternativ där tekniken träsvetsning visat ge en starkare fog än lim. Ur ekologisk synpunkt är plattelement genomgående i trä är att föredra, då det ger en sund konstruktion i full skala, eftersom inga kemikalier eller lagerresurser används. Forskning har visat att massivträ har en positiv och hälsofrämjande effekt på de boende i motsats till effekterna av icke naturliga material. / The increasing use of solid wood construction methods can have a positive impact on the sustainability of constructions. The development of computer-controlled processing techniques enables the solid wood timber industry to rationalize the construction of buildings. The solid wood techniques come at time and will be higher valued in the future due to the natural characteristics of this material. The improvement of solid wood methods has resulted in various techniques to join wood into solid prefabricated parts. There is a need for a comparative market study of the different principles of solid wood construction to widen the knowledge and to explain interested builders the viability of these techniques. The key question for this study is: Which techniques of combining solid wood elements to whole boards are the most favorable ones concerning wood construction buildings – leaving apart questions of production costs, durability and ecological considerations? To point out the utility of these construction techniques and give them a broader understanding a general study of solid wood construction has been presented. The comparative study is based as well on studies of literature as on reviews of 27 companies in 6 countries. The following techniques for the production of boards made of solid timber elements are considered in this report:  Laminating  Nailing  Stapling  Screwing  Stress laminating  Doweling: vertically, horizontally, diagonally and with wooden screws  Dovetailing techniques  Wood welding techniques The study shows that the techniques of solid wood construction are very different in itself. CLT of cross-laminated timber scores highest in terms of cost and durability, but if one considers ecological factors, dovetailing is best. Taking into account both durability and ecological considerations, doweling is best. These alternatives give some freedom of choice regarding the visibility of surfaces and the efficient use of lower qualities of timber and they are therefore suitable for residential construction buildings. CLT is the most cost-effective, not patented and well established option in the market; the development of more health-friendly adhesives is still going on. Current researches demonstrate an alternative: Wood welding joins the parts better together than gluing them. Considered from the ecological viewpoint, boards made exclusively of wood, are preferable since no chemicals or not renewable resources are used. Recent researches show, that solid wood constructions have positive effects on the health of the residents of these buildings in comparison of buildings using non-natural materials. / <p>ORCID-id: 0000-0001-7091-6696</p>