Monitoring vegetation on railway embankments : supporting maintenance decisions

The national railway administrations in Scandinavia, Germany, and Austria mainly resort to manual inspections to control vegetation growth along railway embankments. Manually inspecting railways is slow and time consuming. A more worrying aspect concerns the fact that human observers are often unable to estimate the true cover of vegetation on railway embankments. Further human observers often tend to disagree with each other when more than one observer is engaged for inspection. Lack of proper techniques to identify the true cover of vegetation even result in the excess usage of herbicides; seriously harming the environment and threating the ecology. Hence work in this study has investigated aspects relevant to human variationand agreement to be able to report better inspection routines. This was studied by mainly carrying out two separate yet relevant investigations.First, thirteen observers were separately asked to estimate the vegetation cover in nine imagesacquired (in nadir view) over the railway tracks. All such estimates were compared relatively and an analysis of variance resulted in a significant difference on the observers’ cover estimates (p<0.05). Bearing in difference between the observers, a second follow-up field-study on the railway tracks was initiated and properly investigated. Two railway segments (strata) representingdifferent levels of vegetationwere carefully selected. Five sample plots (each covering an area of one-by-one meter) were randomizedfrom each stratumalong the rails from the aforementioned segments and ten images were acquired in nadir view. Further three observers (with knowledge in the railway maintenance domain) were separately asked to estimate the plant cover by visually examining theplots. Again an analysis of variance resulted in a significant difference on the observers’ cover estimates (p<0.05) confirming the result from the first investigation.The differences in observations are compared against a computer vision algorithm which detects the "true" cover of vegetation in a given image. The true cover is defined as the amount of greenish pixels in each image as detected by the computer vision algorithm. Results achieved through comparison strongly indicate that inconsistency is prevalent among the estimates reported by the observers. Hence, an automated approach reporting the use of computer vision is suggested, thus transferring the manual inspections into objective monitored inspections

Handbok för kombinerade sol- och biovärmesystem : Teknik - System - Ekonomi

Handboken beskriver olika solfångarkonstruktioner och solvärmekretsens ingående komponenter och ger en grundlig inblick i ackumulatortankens konstruktion och funktion. I boken finns förslag på systemutformning, olika tekniska lösningar och hur systemen bör styras och regleras. Handboken beskriver i första hand utformning-lösning-styrning av kombinationen sol- och pelletsvärme, men tar även upp solvärme i kombination med vedpannor, värmedrivna vitvaror och värmepumpar. Värmesystem med vattenburen värme är utmärkta att kombinera med solvärme, men det är i de flesta fall enklare att få till bra lösningar vid nyinstallation, än vid komplettering av befintlig anläggning. När solvärme och pelletsvärme ska kombineras finns det många alternativ till systemutformning. Det är viktigt att vattenburna pelletssystem utformas korrekt och kombineras på rätt sätt med solvärme för att komforten ska bli hög och elanvändningen låg. Vattenmantlade pelletskaminer med ett vattenburet värmesystem är extra intressant i kombination med solvärme. När eldningen upphör i samband med att värmebehovet avtar kan solvärmen ta över. En generell slutsats är att konventionella svenska pelletspannor med inbyggd varmvattenberedning inte är lämpliga i kombination med solvärmesystem. Den typen av bränslepannor ger komplicerade systemlösningar, höga värmeförluster och det är svårt att åstadkomma en tillräckligt bra temperaturskiktning i ackumulatortanken om varmvattenberedning sker i pannan. Solvärme för varmvattenberedning kan vara ett enkelt och bra komplement till pelletskaminer som genererar varmluft. För solvärmesystem är det viktigt att kraftig temperaturskiktning erhålls när värmelagret laddas ur. Det betyder att ackumulatortankens (eller varmvattenberedarens) nedre vattenvolym ska kylas ner till temperaturer som ligger nära ingående kallvattentemperatur. Ackumulatortankens mellersta del bör kylas till samma temperatur som radiatorreturen. Vid design av solfångarkretsen måste överhettning och stagnation kunna klaras utan risk för glykolnedbrytning eller andra skador på värmebärare eller rörkrets (och andra komponenter i kretsen). Partiell förångning minskar risken för att glykolen skadas då solfångaren når höga stagnationstemperaturer. Solfångarens glykolblandning tillåts koka (förångas) på ett kontrollerat sätt så att endast ånga blir kvar i solfångaren. Vätskevolymen i solfångaren samlas upp i ett större expansionskärl och systemet återfylls när vätskan kondenserar. Dränerande solfångarsystem med enbart vatten är ett möjligt alternativ till konventionella solfångare. De kräver en större noggrannhet vid installationen, så att sönderfrysning undviks. Dränerande systemlösningar är relativt ovanliga i Sverige. Om solfångaren under senhöst-vinter-tidig vår kan arbeta med att förvärma kallvatten från 10 till 20 ºC erhålls en betydligt bättre verkningsgrad på solfångaren (och framför allt ökar värmeutbytet då drifttimmarna ökar väsentligt) än om radiatorreturen (som i bästa fall ligger på temperaturnivån 30 - 40 ºC) ska förvärmas. Därför bör radiatorreturen placeras en bra bit upp från botten i ackumulatortanken och tappvarmvattnet ska förvärmas i en slinga som börjar i tankens botten. Om det finns ett VVC-system måste systemet anslutas på ett speciellt sätt så att ackumulatortankens temperaturskiktning inte störs. En viktig parameter vid ackumulatortankens utformning är att värmeförlusterna hålls låga. Det är viktigt för att klara tappvarmvattenlasten med solvärme under mulna perioder sommartid (men också för att hålla energianvändningen låg). I moderna hus, där ackumulatortanken i regel placeras i bostaden, blir det en komfortfråga att undvika övertemperaturer i det rum där värmelagret placeras. En bra standard på isoleringen (med minimerade värmeförluster) kräver att det finns ett lufttätt skikt över hela isoleringen som dessutom sluter tätt mot röranslutningar. Ofrivillig självcirkulation i anslutande kretsar som kan kyla av och blanda om ackumulatortankens vattenvolym, bör förhindras med backventiler och nedböjning av rören i isolerskiktet eller direkt utanför tanken.

Olika yrkesgruppers syn på arbetet kring barn i behov av särskilt stöd inom förskola och skola

Artikelns övergripande syfte är att redovisa hur pedagogisk personal och rektorer i en svensk kommun ser på arbetet kring barn i behov av särskilt stöd. Frågor kring inflytande, påverkan och kompetens samt styrdokumentens betydelse i samband med arbetet kring barn i behov av särskilt stöd ställdes. Personalens och rektorernas syn på orsaker till att barn hamnar i behov av särskilt stöd studerades också. Samtlig pedagogisk personal tillfrågades (N=1345) varav 73 % svarade. Bland rektorerna (N=45) var svarsfrekvensen 100 % . Den teoretiska ansatsen är socialkonstruktivistisk och verksamhetsteorin har använts för att studera och analysera kommunen och skolan som system. Resultaten visar bland annat att drygt en fjärdedel av all pedagogisk personal i kommunen anser att de har små möjligheter att påverka barns måluppfyllelse, att de flesta anger att speciallärare/specialpedagoger ska ha störst inflytande över arbetet kring barn i behov av särskilt stöd samt att orsakerna till att barn hamnar i behov av särskilt stöd oftast anses bero på barnets individuella brister.

Studies of new inorganic species using relativistic quantum chemistry

In the present work the methods of relativistic quantum chemistry have been applied to a number of small systems containing heavy elements, for which relativistic effects are important. First, a thorough introduction of the methods used is presented. This includes some of the general methods of computational chemistry and a special section dealing with how to include the effects of relativity in quantum chemical calculations. Second, after this introduction the results obtained are presented. Investigations on high-valent mercury compounds are presented and new ways to synthesise such compounds are proposed. The methods described were applied to certain systems containing short Pt-Tl contacts. It was possible to explain the interesting bonding situation in these compounds. One of the most common actinide compounds, uranium hexafluoride was investigated and a new picture of the bonding was presented. Furthermore the rareness of uranium-cyanide compounds was discussed. In a foray into the chemistry of gold, well known for its strong relativistic effects, investigations on different gold systems were performed. Analogies between Au$^+$ and platinum on one hand and oxygen on the other were found. New systems with multiple bonds to gold were proposed to experimentalists. One of the proposed systems was spectroscopically observed shortly afterwards. A very interesting molecule, which was theoretically predicted a few years ago is WAu$_{12}$. Some of its properties were calculated and the bonding situation was discussed. In a further study on gold compounds it was possible to explain the substitution pattern in bis[phosphane-gold(I)] thiocyanate complexes. This is of some help to experimentalists as the systems could not be crystallised and the structure was therefore unknown. Finally, computations on one of the heaviest elements in the periodic table were performed. Calculation on compounds containing element 110, darmstadtium, showed that it behaves similarly as its lighter homologue platinum. The extreme importance of relativistic effects for these systems was also shown.

Struggles over resources and representations in territorial conflicts in the Northern Autonomous Atlantic Region (RAAN), Nicaragua

Territoriality is a central issue in indigenous peoples struggles. The territorial struggles involve struggles over the control of natural resources and over political participation and representation, but also over the perception of territorial rights and the symbolic representation of the territory. These struggles are carried through both in material and symbolic ways through recurring to different discourses and representations that provide legitimation for the territorial claims of the group. The study is located in the Northern Autonomous Atlantic Region of Nicaragua. The study concerns the territorial strategies, conceptions and practices of the indigenous people and other actors. Territorial conflicts exist between the autonomous region and the central government of Nicaragua, between mestizo settlers and indigenous people, between different indigenous groups, and between these and development agents such as conservation projects. The study focuses on how territorial discourses and representations are used to legitimate territorial control. Environmental, historical and cartographical discourses are the most important discourses recurred to. The influence of discourses and representations on the territorial practices and policies of the different actors, the links between the local struggles and global processes, and the broader structural factors impacting on the territorial struggles are also analysed. Among the structural factors are the problems related to land tenure and management and the use of natural resources, the advance of the agricultural frontier, the institutional weaknesses of the central and regional governments and the legislative processes. The territorial discourses are both recurred to in a strategic way and also grounded in local ideals and practices. The discourses have produced real effects for example in legislation, land tenure systems, political representation and environmental practices. Although the use of discourses and representations are an important power tool in territorial struggles, territorial control cannot be effectively accomplished merely through representing territorial claims in a legitimate way or through reforming legislation, as the conflicts are also largely a result of structural factors affecting the region. The fieldwork was carried out during a total of twelve months between 2000 and 2002. The research methods used were semi-structured interviews, participant observation and participatory research methods. A broad range of literary sources were also used to collect data. The study is located within the field of critical political geography with a discursive political ecology approach. It can be called a critical realist approach to the discursive analysis of indigenous territoriality.

Computational Methods for Studies of Quantum Dots and Boson Condensates

This thesis presents ab initio studies of two kinds of physical systems, quantum dots and bosons, using two program packages of which the bosonic one has mainly been developed by the author. The implemented models, \emph{i.e.}, configuration interaction (CI) and coupled cluster (CC) take the correlated motion of the particles into account, and provide a hierarchy of computational schemes, on top of which the exact solution, within the limit of the single-particle basis set, is obtained. The theory underlying the models is presented in some detail, in order to provide insight into the approximations made and the circumstances under which they hold. Some of the computational methods are also highlighted. In the final sections the results are summarized. The CI and CC calculations on multiexciton complexes in self-assembled semiconductor quantum dots are presented and compared, along with radiative and non-radiative transition rates. Full CI calculations on quantum rings and double quantum rings are also presented. In the latter case, experimental and theoretical results from the literature are re-examined and an alternative explanation for the reported photoluminescence spectra is found. The boson program is first applied on a fictitious model system consisting of bosonic electrons in a central Coulomb field for which CI at the singles and doubles level is found to account for almost all of the correlation energy. Finally, the boson program is employed to study Bose-Einstein condensates confined in different anisotropic trap potentials. The effects of the anisotropy on the relative correlation energy is examined, as well as the effect of varying the interaction potential.}

Rapport från 20th European Photovoltaic Solar Energy Conference and Exhibition : Barcelona 6-10 juni 2005

På uppdrag av STEM bevakade Eva Lindberg från Centrum för solenergi-forskning, SERC, Högskolan Dalarna, 20th European Photovoltaic Solar Energy Conference and Exhibition, Barcelona, 6-10 juni 2005. Ca 1700 personer fanns på deltagarlistan. På grund av konferensen omfattning kan endast ett litet urval av föredrag och utställare kommenteras i rapporten. Konferensprogrammet var indelat på följande områden:1. Grundläggande fakta, nya komponenter och material2. Kristallina kiselsolceller and materialteknologi3. Amorft och mikrokristallint kisel4. CIS, CdTe och andra (II-VI) ternära tunnfilmsceller5. PV-moduler och komponenter i PV-system6. PV-system i nätanslutna applikationer7. Globala aspekter på PV-solelektricitet8. PV-industrins resultatFoU om kristallina solceller dominerade stort, sedan tunnfilmsceller av främst amorft kisel. Intressant var att återvinning är föremål för FoU; dels återvinning av kiselsolceller när panelen tjänat ut; dels återvinning av Cu, Cd, Se och Te när tunnfilmscellerna tas ur bruk.237 företag fanns representerade i utställningen, varav 20 från Kina. Tyskland dominerade stort. Utställningen teman var följande: 1) Tillverkare av kiselplattor, solceller, PV-moduler, koncentratorer, solföljare (se bild nedan) 2) Tillverkare och återförsäljare av utrustning och material 3) Integrering och distribution av system 4) Mätningar och kontrollteknologi 5) Forskning och laboratorier 6) Service, teknik, konsulting 7) Myndigheter och föreningar 8) Media och förlag 9) Tillverkare av inverterare 10) Övrigt.

Decision Making for Teams of Mobile Robots

In the past years, we could observe a significant amount of new robotic systems in science, industry, and everyday life. To reduce the complexity of these systems, the industry constructs robots that are designated for the execution of a specific task such as vacuum cleaning, autonomous driving, observation, or transportation operations. As a result, such robotic systems need to combine their capabilities to accomplish complex tasks that exceed the abilities of individual robots. However, to achieve emergent cooperative behavior, multi-robot systems require a decision process that copes with the communication challenges of the application domain. This work investigates a distributed multi-robot decision process, which addresses unreliable and transient communication. This process composed by five steps, which we embedded into the ALICA multi-agent coordination language guided by the PROViDE negotiation middleware. The first step encompasses the specification of the decision problem, which is an integral part of the ALICA implementation. In our decision process, we describe multi-robot problems by continuous nonlinear constraint satisfaction problems. The second step addresses the calculation of solution proposals for this problem specification. Here, we propose an efficient solution algorithm that integrates incomplete local search and interval propagation techniques into a satisfiability solver, which forms a satisfiability modulo theories (SMT) solver. In the third decision step, the PROViDE middleware replicates the solution proposals among the robots. This replication process is parameterized with a distribution method, which determines the consistency properties of the proposals. In a fourth step, we investigate the conflict resolution. Therefore, an acceptance method ensures that each robot supports one of the replicated proposals. As we integrated the conflict resolution into the replication process, a sound selection of the distribution and acceptance methods leads to an eventual convergence of the robot proposals. In order to avoid the execution of conflicting proposals, the last step comprises a decision method, which selects a proposal for implementation in case the conflict resolution fails. The evaluation of our work shows that the usage of incomplete solution techniques of the constraint satisfaction solver outperforms the runtime of other state-of-the-art approaches for many typical robotic problems. We further show by experimental setups and practical application in the RoboCup environment that our decision process is suitable for making quick decisions in the presence of packet loss and delay. Moreover, PROViDE requires less memory and bandwidth compared to other state-of-the-art middleware approaches.

IT-system och organisationsutveckling

This report describes work on the thesis “IT systems and organizational development”. The work is carried out on Stocksbro Energi AB, during spring 2009. The company wanted better flow in their production but also review if the inventory management function located in Visma SPCS Administration 2000, could be used in the organization. Under the first part of this report the system were tested to ensure if the system would work together with the organization. After testing the desired features they were evaluated along with two of the users to the system at the company. The wanted functions could not be obtained whenthe Admin 2000 is an economic system and are not made for the producing companies. Thereafter the theoretical possibility was examined of introducing a more advanced system to get the desired functionality to work together with the organization. To introduce a more advanced system will require major changes of the organization, before, during and after the introduction. It is therefore important how the management implements a possibility of a new system. It’s important to make the staff join in this implementation but also get as much as possible out of the system.To conclude the thesis a goal and problem analysis but also a solution proposal was made with the help of the FA/SIMM method. Also some suggestions are mentioned how the company could proceed in the implementation of the proposals for a solution.

Studie av subsynkron interaktion (SSTI) mellan ett HVDC system med spänningsstyva strömriktare och en närliggande generator

Syftet med examensarbetet är att studera den subsynkrona interaktionen (subsynchronous torsional interaktion, SSTI) mellan ett HVDC system med spänningsstyva strömriktare och en närliggande generator. Studien utförs med hjälp av datorsimuleringar och fokuserar på att studera dämpkaraktäristiken för SSTI. Studien ska visa hur faktorer såsom den överförda effektens storlek och riktning, vald driftmod och kraftsystemets kortslutningseffekt påverkar dämpkaraktäristiken. Rapporten beskriver subsynkron oscillation (SSO) och tillvägagångssättet vid en SSTI undersökning. En kort introduktion till HVDC Light ges. Studien visar att HVDC Light ökar dämpningen för det frekvensområde som är intressant. Resultaten presenteras som diagram med beräknad dämpkaraktäristik.

The paribhasas arthavadgrahane nanarthakasya, laksanapratipadoktayoh pratipadoktasyaiva grahanam and ekadesavikrtam ananyavat : Studies on some Metarules in Paninian system

In his grammatical treatise, the Astadhyayi, Panini includes sutras that state guiding rules for the right interpretation and application of his other directly grammatical sutras. These sutras are called paribhasas. In addition to these paribhasas, the various commentaries on Panini frequently invoke supplementary paribhasas which are not stated explicitly in his Astadhyayi. These paribhasas have been a subject of study since early times after Panini and have also occupied modern scholars on Panini s grammar. In regard to most of them, it remains unsettled even today whether they are used in the Astadhyayi, where they apply, what is their role, and whether they are necessary in arriving at the desired grammatical form. Some scholars go even further and argue that none of such paribhasas were intended by Panini. This study aims to settle this question by dealing with three such of these paribhasas individually considering all the information available in the commentaries in their regard and examining the cases in which, according to commentaries, the paribhasas apply. I select the paribhasas arthavadgrahane nanarthakasya, laksanapratipadoktayoh pratipadoktasyaiva grahanam and ekadesavikrtam ananyavat, which are all considered nyayasiddha or lokanyayasiddha; they express logical and obvious principles which are found in daily life. On this basis, Paniniyas explain why Panini did not mention them in the Astadhyayi. I discuss each paribhasa separately and all the issues it involves. I present and explain the cases where the specified paribhasas are invoked in the major commentaries, the Mahabhasya, the Kasika and the Siddhantakaumudi and the arguments found in the commentaries concerning these cases. If available, I supply other solutions to the difficulties for which these paribhasas are invoked. The study aims to make the issue of these paribhasas clearer, which will help us to reach a solution to the key question, that is, whether Panini has presupposed them in his Astadhyayi. My study shows that Panini has presupposed the paribhasa ekadesavikrtam ananyavat (or a similar principle). He also may have used the paribhasa arthavadgrahane nanarthakasya (or a similar principle) as this paribhasa does not lead to undesired results. As for the paribhasa laksanapratipadoktayoh pratipadoktasyaiva grahanam (or a similar principle), the original scope of this paribhasa was clearly extended by later Paniniyas. Moreover, their interpretation of this paribhasa conflicts with Panini s procedure. If Panini has used this paribhasa, he has used it in a very limited way.