Reversibilitetsproblemet för tvådimensionella cellulära automater

I den här avhandlingen behandlas cellulära automater och speciellt deras reversibilitet. Avhandlingens fokus ligger vid att bevisa att reversibilitetsproblemet är oavgörbart för tvådimensionella cellulära automater, med andra ord att det inte existerar en algoritm för att bestämma om en tvådimensionel cellulär automat är reversibel. Avhandlingen inleds med introduktionen av grundläggande definitioner och begrepp gällande cellulära automater. I kapitel 2 undersöker vi existensen av Edens trädgård-konfigurationer hos cellulära automater. En Edens trädgård-konfiguration är en konfiguration som endast kan förekomma som startkonfiguration hos den cellulära automaten ifråga. Vi bevisar också Edens trädgård-satsen som ursprungligen presenterades av Edward F. Moore och John Myhill. Tillsammans med Curtis-Hedlund-Lyndon satsen som presenteras i kapitel 3, möjliggör Edens trädgård-satsen beviset av att en cellulär automat är reversibel om och endast om dess globala funktion är injektiv. Detta bevis presenteras i kapitel 3 och utgör en grundläggande ingredient i beviset av att reversibilitetsproblemet är oavgörbart för tvådimensionella cellulära automater. I kapitel 4 bekantar vi oss med begrepp som krävs för att förstå vad oavgörbarhet innebär. Begrepp som behandlas är bl.a. Turingmaskin och algoritm. Kapitel 5 inleds med introduktionen av kaklingsproblemet samt diverse viktiga definitioner i anknytning till detta problem. Här presenteras och bevisas också en sats som utgör det sista grundantagandet i beviset av reversibilitetsproblemets oavgörbarhet för tvådimensionella cellulära automater. Detta bevis behandlas i avhandlingens sista kapitel

Preaching in times of the European ‘Refugee Crisis’: Scandinavian perspectives

Toward the end of 2015, 65.3 million people were seeking refuge or were otherwise forcibly displaced globally. This is the largest number since the recordings began around World War II. In Europe more than 1 million people arrived by sea in 2015 – more than four times as many as the previous year.1 The crisis situation stirred public debate as well as church-based initiatives trying to deal with the situation. In order to understand the interaction between public discourse and local preaching a group of homileticians from seven European countries collaborated on an empirical study of how the refugee crisis impacted preaching. In what follows we present the initial results from the Scandinavian countries

Microclimatological consequences for plant and microbial composition in Sphagnum-dominated peatlands

In three Scandinavian peatlands we studied to what extent plant and microbial community compositions are governed by local-scale microhabitat, with a special interest in the effect of aspect (i.e. exposition of slopes). Despite differences in solar irradiance between the south- and north-facing slopes, maximum temperature was elevated in the south-facing slopes at the most northern site only. Pore-water nutrient concentrations were not affected by aspect, yet dissolved organic carbon concentrations were higher in the south-facing microhabitats. This was likely caused by higher vascular plant biomass. Plant and microbial community composition clearly differed among sites. In all three sites, microhabitat (i.e. prevailing water-table depth) affected the plant and microbial community compositions. Aspect, however, did not affect community composition, even though microclimate significantly differed between the south- and the north-facing aspects at the northernmost site. Our results highlight the complex link between plant community composition, microbial community and environmental conditions, which deserves much more attention than currently in order to fully understand the effects of climate change on peatland ecosystem function.I

Nitrifyers in constructed wetlands treating landfill leachates

Landfill leachate is produced many years after a landfill site closes. Hence, treatment by “natural methods”, as e.g. constructed wetlands, with low management requirements is attractive. Constructed wetlands usually provide both shallow and deep areas with aerobic and anaerobic zones, which is suitable for nitrification followed by denitrification of the ammonium-rich leachates. Full-scale treatment systems are influenced by climatic variables that affect the microbial community. Also, the operational strategy can have a considerable impact on both activity and composition of the microorganisms. Many studies have measured inflow/outflow water quality in treatment systems. Such “black box” studies describe the treatment efficiency but add little to an increased understanding of theorganisms performing the treatment or the spatial distribution of their activities and treatment processes. In this thesis we investigated seasonal and annual changes in potential nitrification and denitrification, and in the corresponding bacterial communities in constructed wetlands treating landfill leachates. Variations in the potential activity in full-scale systems were investigated over several years, using short-term incubation. The composition of the bacterial communities was investigated using a group-specific PCR primer pair targeting the 16S rRNA genes or a primer pair targeting the funtional gene nosZ. The PCR products were analysed by denaturing gradient gelelectrophoresis and subsequent nucleotide sequencing and phylogentic analysis. A stable ammonia-oxidising bacterial (AOB) community composition and potential ammonia-oxidation (PAO) were detected in the system with a year-round operation. On the other hand, changes in the AOB community composition which followed the operational schedule were detected in the overland flow area (OFA) running seasonally. Furthermore, the influence of operational strategy was indicated by a low PAO in the wastewater overland flow area and compact constructed wetland receiving high hydraulic loads, indicating the value of aeration. Higher PAO was detected in the OFAs where the hydraulic load followed literature guidelines. All systems supported diverse AOB communities, represented by several Nitrosomonas and Nitrosospira populations. The number of different populations detected in these wetlands was much higher than reported in municipal wastewater treatment plants, and differed from those in a parallel OFA treating municipal wastewater. Furthermore, the large variation in both potential activity and sequences detected in replicate samples suggests that such systems are spatially heterogenic

Here is a Lot of Space : Theologies of Preaching in a Complex Reality

The purpose of this dissertation is to understand the complexity of the preaching event as communication from a theological point of view in order to increase the awareness of this complexity. I see theology of preaching as a way of reducing the complexity, to making the complexity visible. I study the contemporary preaching theologies that Eberhard Jüngel, Mary Catherine Hilkert, W. Paul Jones and Rebecca S. Chopp construct. They reduce the complexity of the preaching event to understand it better, and by doing so they make the complexity visible. In the introduction I discuss some factors that make the preaching event complex:- the complexity of human interactive communication in general; that preaching is thought to be an event in which God communicates and the ambigous use of signs for the purpose of communication. I give a brief background to this homiletical situation, by describing some patterns in the linguistic and postmodern turns. The method of this study is a reduction of the complexity of the preaching theologies that I present. To do this I use the words situation (the human situation in the preaching situation), event (the salvatory event that the preaching event is thought to be a part of) and function ( the function of the sermon) and their interrelationship. The sermon is thought to get it´s function in the situation as a part of the event. I also discuss some consequenses of the specific theology of preaching and the view of the preacher; the church and liturgy; the Biblical texts; and the language, form and content of the sermon. The main part of the study consists of the anlysis of the four reductions of complexity, and their different prespectives on preaching, where Jüngel uses the doctrine of justification by faith to give structure to thought, Hilkert uses sacramental and dialectic imagination, Jones uses a typology of five theological worlds and Chopp use the metaphor text/margin to give structure to thought. I present the four theologies of preaching as a polyphonic voice, that makes us aware of the complexity of the preaching event. They constribute to the important theological conversation about preaching in our complex reality

Cost engineering: Kostnadsidentifiering i en verksamhet : En fallstudie om identifiering av osynliga kostnader

Det har alltid varit viktigt för företag i alla branscher att ständigt kunna fatta rätt beslut. För att kunna göra det måste företagen vara medvetna om vilka kostnader som finns och kan uppstå i deras verksamhet. För att kunna göra en rättvis kostnadsuppskattning bör företag även sträva efter att identifiera osynliga kostnader. Detta arbete baseras på en fallstudie som genomfördes på företaget LKAB som bedriver gruvverksamhet. Syftet med denna studie var att utreda huruvida osynliga kostnader och förlorade intäkter existerar och i så fall var och i vilken mån de bör beaktas. Studiens mål var att ta fram ett underlag som ska kunna tillämpas i effektiviserings syfte hos olika företag. Studiens frågeställningar kunde besvaras. Med hjälp av intervjuer utformades en värdeflödeskarta som påvisade var kostnader uppstår. En ABC-kalkyl användes för att kunna identifiera kopplingen mellan kostnader och deras aktiviteter och resurser. För att kunna avgöra vilka av kostnaderna och de förlorade intäkterna som bör påverkas användes Leans definition på slöseri. Resultatet som erhölls visade på att osynliga kostnader och förlorade intäkter existerar samt i vilken mån de bör beaktas och hanteras vid den taktiska planeringen. De kostnader som bör påverkas visade sig vara Demurrage-kostnaden, transportkostnaden och särhanteringskostnaden. De förlorade intäkterna som inte visade sig skapa något värde för kunden och då borde beaktas var dödfrakt, fraktkompensation, rabatterat pris och förlorade intäkter som uppstår i samband med produktionsstopp och produktkassering. Resultatet visade även på att det går att få ett användbart resultat utan att använda en ABC-kalkyl fullt ut.   Before making a decision based on a fair cost estimate, careful consideration should be given to ensure that invisible operational costs have been adequately identified and incorporated into the estimate. We present the results of a case study conducted at the Swedish mining company LKAB in which we investigated to what extent do invisible costs exist, their impact on lost revenue, and whether they can be adequately captured within the framework of a fair cost estimate. Using data obtained from a series of interviews conducted at LKAB, we built a value-flow chart to model costs and used an ABC calculation to determine the linkage between the costs and their activities and resources. We then applied Lean's definition of waste to identify which, and to what extent, these costs and lost revenue should be affected. Specifically, we determined that the costs which should be considered are: Demurrage, transport, and special handling and the sources of lost revenue are: dead freight, freight compensation, discounted prices, production stoppages, and discard a product. Finally, our analysis showed that fair cost estimates including invisible costs and lost revenue are useful in making decisions about the efficiency of a company and that a full ABC calculation is not required to get a useful result.

Lek och lärande i förskolan

Sammanfattning: Examensarbetet fokuserar på lekens betydelse för lärandet i förskolan och pedagogers syn på den reviderade Lpfö98. Vår problemställning handlar om att få en ökad förståelse för den styrda verksamheten, som syftar till att uppfylla strävansmålen kontra den fria leken, där barnen får utforska sig själva och sin miljö. Examensarbetet syftar till att skapa förståelse för hur pedagogerna förhåller sig till den styrda respektive den fria leken och hur pedagogerna arbetar med att integrera strävansmålen i verksamheten. Vi har valt att använda oss av kvalitativa och semistrukturerade intervjuer som metod i vårt arbete. Vi fick möta sex pedagoger på två olika förskolor. I examensarbetets resultat kan vi se att de pedagoger vi intervjuade anser att strävansmålen inte inverkar på den fria leken. Vi kan också se att dokumentationen vad gäller strävansmålens uppfyllelse är tidskrävande. Pedagogerna upplever att Lpfö98 rev.10 är konsekvent, tydlig och ger förutsättningar för en bra verksamhet

Optimering av maskinsystem för skörd av ensilage med hög kvalitet

This study examines harvesting systems and presents conclusions on selection of machines for harvesting silage for dairy cows. Achieving a high quality cut of forage requires a high machine capacity and harvesting must be carried out at the optimal time with respect to plant growth stage. Therefore calculation of timeliness costs, which are determined by the time and capacity of harvesting, formed an important part of the study. These calculations require timeliness factors that describe the losses for each day by which harvest is delayed after the date of maximum economic crop value. The timeliness factors were calculated for each cut from data on changes in yield and quality of cuts during the harvest period. Harvesting cost calculations were based on a precision chop forage trailer, a precision chop forage harvester with separate transport trailers and a round baler with integral wrapping. Cost calculations were carried out for three different sizes of machine chain (small (S), medium (M) and large (L)) for each harvest system. The operations included were mowingconditioning, harvesting in the field, transport to storage and loading and packing into a bunker silo. Harvesting costs included the cost of machines, labour and timeliness. In addition, ensiling costs such as bale plastic and the investment, interest and maintenance cost for the bunker silo or the storage area for round bales were included when comparing the harvesting systems. Calculations were made for a three-cut system in conventional (CONV) and organic (ORG) forage production in southern Sweden (Gss) and central Sweden (Ss). When timeliness costs were not considered there was a risk of too low a harvest capacity being chosen. The effect of including timeliness costs when calculating harvesting costs increased with the forage area harvested, since a larger forage area increased the duration of harvest. Table S1 shows harvesting and ensiling costs with 1 km transport distance for 70 hectares of forage in conventional production and 90 hectares in organic production in central Sweden. At short transport distances (1 km), the precision chop forage trailer and the precision chop forage harvester with separate transport trailers had similar harvesting and ensiling costs, while those for round baling were somewhat higher. The precision chop forage harvester with 2 or 3 transport trailers resulted in the lowest costs at 2-7 km transport distance. At longer transport distances (>7 km), the round baler was the cheapest of the harvesting systems studied here. As regards machine capacity, it is clear from Figure S1 that to minimise harvesting costs the smallest machine chain should be used for forage areas less than 60 ha, whereas when the forage area exceeds 90 ha the largest machine chain should be chosen. In the 60-90 ha forage area range, there was little difference in costs between the S, M and L machine chains. For harvest with round bales only the size of the mower-conditioner varied between the machine chains and the largest machine chain had the lowest harvest costs for all forage areas. Machine cooperatives are a good way to lower harvesting costs since for smaller forage areas in particular, increased annual use of the machines decreases the machine costs and allows larger machines to be used to greater capacity. To avoid high timeliness costs it is important that cuts are performed at the optimal time