Guidance algorithms for a free-flying space robot

Robotics is a promising technology for assembly, servicing, and maintenance of platforms in space. Several aspects of planning and guidance for telesupervised and fully autonomous robotic servicers are investigated. Guidance algorithms for proximity operation of a free flyer are described. Numeric trajectory optimization is combined with artificial intelligence based obstacle avoidance. An initial algorithm and the results of its simulating platform servicing scenario are discussed. A second algorithm experiment is then proposed

Artificial intelligence applications in teleoperated robotic assembly of the EASE space structure

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, and Dept. of Electrical Engineering and Computer Science, 1988.Bibliography: leaf 197.by Herbert E. M. Viggh.Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, and Dept. of Electrical Engineering and Computer Science, 1988

SPIRE algorithms

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 393-396).In this thesis we address the problem of estimating changes in surface reflectance in hyperspectral image cubes, under unknown multiplicative and additive illumination noise. Rather than using the Empirical Line Method (ELM) or physics-based approaches, we assumed the presence of a prior reflectance image cube and ensembles of typical multiplicative and additive illumination noise vectors, and developed algorithms which estimate reflectance using this prior information. These algorithms were developed under the additional assumptions that the illumination effects were band limited to lower spatial frequencies and that the differences in the surface reflectance from the prior were small in area relative to the scene, and have defined edges. These new algorithms were named Surface Prior Information Reflectance Estimation (SPIRE) algorithms. Spatial SPIRE algorithms that employ spatial processing were developed for six cases defined by the presence or absence of the additive noise, and by whether or not the noise signals are spatially uniform or varying. These algorithms use high-pass spatial filtering to remove the noise effects. Spectral SPIRE algorithms that employ spectral processing were developed and use zero-padded Principal Components (PC) filtering to remove the illumination noise. Combined SPIRE algorithms that use both spatial and spectral processing were also developed. A Selective SPIRE technique that chooses between Combined and Spectral SPIRE reflectance estimates was developed; it maximizes estimation performance on both modified and unmodified pixels. The different SPIRE algorithms were tested on HYDICE airborne sensor hyperspectral data, and their reflectance estimates were compared to those from the physics-based ATmospheric REMoval (ATREM) and the Empirical Line Method atmospheric compensation algorithms. SPIRE algorithm performance was found to be nearly identical to the ELM ground-truth based results. SPIRE algorithms performed better than ATREM overall, and significantly better under high clouds and haze. Minimum-distance classification experiments demonstrated SPIRE's superior performance over both ATREM and ELM in cross-image supervised classification applications. The taxonomy of SPIRE algorithms was presented and suggestions were made concerning which SPIRE algorithm is recommended for various applications.by Herbert Erik Mattias Viggh.Ph.D

Normbrytande eller normbekräftande? En kvalitativ innehållsanalys av TV-serien "Girls" utifrån ett genusperspektiv

Abstract Studiens syfte är att kritiskt analysera TV-serien Girls, en serie som tillskrivits egenskaper som implicerar en normkritisk och banbrytande framställning av unga kvinnor i dagens amerikanska medelklassamhälle. I förlängningen syftar studien till att undersöka huruvida dagens visuella medier bidrar till att bekräfta eller utmana den rådande könsmaktsordningen och där tillhörande normer. Är TV-serien Girls normkritisk och banbrytande vad gäller framställningen av unga kvinnors livsvillkor i relation till utseende och kroppsuppfattning, sexualitet, maktstrukturer mellan könen samt de konventioner och stereotyper som existerar för män respektive kvinnor? Studien vilar på den hermeneutiska läran om tolkning och förståelse och präglas vidare av ett perspektivistiskt ställningstagande till vad som är befintlig sanning. Den huvudsakliga metoden i uppsatsen sorterar under diskursiv innehållsanalys som har kompletterats med observationsverktyg från främst semiotiken men även från narratologi. Analyserat material består av den första säsongen av Girls, tio avsnitt á ca 30 minuter. Som komplement och referenspunkt användes även samtliga tio avsnitt av SVTs paneldiskussion TV-cirkeln: Girls. Resultatet av studien visar på en delvis normbrytande syn på och framställning av kvinnans kropp och sexualitet samt konventioner och maktstrukturer inom sociala relationer, men tycks även på många vis vara en reproducent av rådande normer. Resultat visar på en dubbelsidig och komplicerad relation till genusvetenskapliga teorier om könskonventioner och köns olikartade framställning i medier. Key words: Girls, genus, innehållsanalys, feminism, sexualitet, kroppsuppfattning, stereotyp Normbrytande eller normbekräftande? En kvalitativ innehållsanalys av TV-serien ”Girls” utifrån ett genusperspektiv Emma Viggh & Ida Wallin Institutionen för kommunikation och medier, Lunds universite

"Oj, mamma har friendat mig!"

B-uppsats i Medie- och kommunikationsvetenskap vid Institutionen för Kommunikation och Medier; “Oj, mamma har friendat mig!”. En kvalitativ studie i föräldrar- barnrelationen på facebook”, författad av Emma Viggh & Ida Wallin vid Lunds Universitet. Nyckelord: Facebook, Sociala medier, Identitet, Relationer, Ungdomar, Föräldrar Samtidens medievardag bäddar för en helt ny situation då tidigare åtskilda parter, som arbetsgivare och anställda, föräldrar och barn, nu möts och interagerar i samma sociala nätforum. En process som särskilt avspeglas i vårt valda medium, Facebook. Vi har i följande studie valt att se djupare vid just det sistnämnda; föräldra- barnrelationen och den komplexa situation som kan komma att uppstå då föräldrar närvarar och bevakar sin ungdoms skapande av det egna jaget, detta i en tid då autonomi och frigörelse från tidigare nära hållna parter är en viktig process för ungdomen. Vårt syfte med studien är att undersöka hur tonåringar i åldern 16-18 år använder och upplever mediet Facebook i relation till föräldrarnas närvaro i samma nätverk. Vi har i studien utgått ifrån ett kvalitativt tillvägagångssätt och utfört semistrukturerade och personliga intervjuer med sju (7) utvalda respondenter. Vi framställde till intervjutillfället en övergripande intervjuguide som inleddes med kartläggande frågor och avslutades med frågor av mer öppen karaktär. Respondenterna är alla mellan 16-18 år och har en eller flera föräldrar som ”vän” på Facebook. Vi kan efter studiens genomförande konstatera att våra respondenters inställning till föräldrarnas närvaro på mediet Facebook präglas av viss komplexitet. Det finns en problematik i den uppkomna situtationen då somliga av ungdomarna känner sig påpassade och obekväma med föräldrarnas närvaro. Tillika vittnar vissa respondenter om konflikter som uppstått mellan dem och föräldrarna rörande publicerat material på mediet. Vi kan samtidigt se en återkommande positiv inställning till föräldranärvaron, bland annat genom respondentens upplevelse av att föräldern kan uppnå en ökad tilltro till hen genom den nya uppsiktsmöjligheten, men även genom en mer tilltagen vardagskontakt förälder och barn emellan. Vi reflekterar kring möjligheten att ungdomarna inte längre befinner sig i ett frigörelsestadium gentemot föräldern utan snarare är på väg in i en fas av återanknytning

Mission planning for space based satellite surveillance experiments with the MSX

The Midcourse Space Experiment is a BMDO-sponsored scientific satellite set for launch within the year. The satellite will collect phenomenology data on missile targets, plumes, earth limb backgrounds and deep space backgrounds in the LWIR, visible and ultra-violet spectral bands. It will also conduct functional demonstrations for space-based space surveillance. The Space-Based Visible sensor, built by Lincoln Laboratory, Massachusetts Institute of Technology, is the primary sensor on board the MSX for demonstration of space surveillance. The SBV Processing, Operations and Control Center (SPOCC) is the mission planning and commanding center for all space surveillance experiments using the SBV and other MSX instruments. The guiding principle in the SPOCC Mission Planning System was that all routine functions be automated. Manual analyst input should be minimal. Major concepts are: (I) A high level language, called SLED, for user interface to the system; (2) A group of independent software processes which would generally be run in a pipe-line mode for experiment commanding but can be run independently for analyst assessment; (3) An integrated experiment cost computation function that permits assessment of the feasibility of the experiment. This paper will report on the design, implementation and testing of the Mission Planning System

Production and hydration of calcium sulfoaluminate-belite cements derived from aluminium anodising sludge

Calcium sulfoaluminate-belite cement (CSAB) offers lower CO2 emissions in its production, compared with Portland cement. However, for the production of CSAB a high amount of alumina is required, and the scarcity and high cost of high-purity bauxite make these cements costly at present. In this study, the use of uncalcined aluminium anodising sludge (AAS) as the main source of alumina to produce CSAB clinkers, replacing bauxite, was assessed. The CSAB clinkers produced were mainly composed of ye’elimite and belite, along with minor traces of alite, and/or brownmillerite, depending on the alumina source. Clinkers derived from AAS as a source of aluminium showed a lower content of ye’elimite (35.5%), as well as the formation of alite (8.2%) when compared to a reference clinker produced with reagent-grade materials. Comparable hydration products were identified in the hydrated cements independent of the alumina source used. The use of AAS to produce CSAB cement was proven to be technically feasible, and the cement thus produced has desirable technical characteristics, presenting high mechanical strength (>40 MPa in paste samples)

Modellering av inverkan av magnesium från alternativa råmaterial på Portland cementklinker kemi

The methods used in this thesis work were a combination of computational and modeling based laboratory experiments. Thermodynamic process modeling of the cement clinker process offers a tool for evaluating how changes in raw materials and process parameters affect the clinker quality. Work with finding suitable replacement raw materials involves investigating the chemical compatibility of potential alternative materials. Such replacement materials may be metallurgical slags, although there are some unsolved issues with the quantities of certain metals and particularly Mg in these materials. For predicting the formation of clinker mineral phases, cooling calculations are used in order to reproduce the temperature history in the full scale process. A chemistry model including a solid solution phase based on C2S and phosphate was developed along with the recommendation for continued work on clinker phases with solid solutions to include MgO. A thermodynamic database for phase chemistry calculations of clinkering reactions was created and evaluated. Suitable compounds and solution species were selected from the thermochemical database included in FactSage software. The extent and quality of the required thermodynamic data via available databases is generally satisfactory, except for certain properties of some of the main clinker phases. One example is the lack of a thermodynamic model for the alite solid solution. That is, the composition of the phase available in the database representing alite does not contain the minor elements Al, Fe and Mg. Therefore, it is difficult to predict the quantity and distribution of Mg in the clinker, with varying total content of MgO. Thus, one of the goals/objectives was to improve thethermodynamic model of alite as a solid solution of 3CaO-SiO2-xAl2O3-yFe2O3-zMgO. To achieve this, it was assumed that a mix of compounds with adjusted Henrian coefficients representing the solid solution clinker phase alite was in equilibrium with the clinker melt. The distribution of MgO was studied in synthetic clinker compositions with quantities ranging from 0.5 to 10 wt-%. Synthetic clinker mixes were heated to 1450°C and studied with Rietveld refinements of X-ray diffraction data and SEM-EDS analysis. In addition, the mechanisms of how slag and lime particles react facilitating the diffusion of MgO into the developing clinker melt and the formation of incipient belite were studied. The calculated results provide a good prediction of the quantities and composition of the clinker phases formed during heating and non-equilibrium cooling. The solubility of MgO in the clinker and the quantity of periclase formed is in fair agreement with published data. Thus, this thesis work shows that using a mix of compounds with adjusted activities in alite together with available standard thermodynamic data and the Scheil cooling method had good potential for evaluating alternative raw materials. Also, the work has identified weak points in the process modeling and suggest improvements to be made in future research work

Mangan i cementdamm

Manganese is a heavy metal that acts an essential micronutrient for plants and animals, as well as it is toxic in great amounts. Mn2+ is the form of manganese that is biologically available for plants and micro organisms living in soil. How much manganese a plant needs and tolerates varies greatly among different species. The amount of available manganese in soil also varies among different soil types, depending on the origin of the minerals in the soil. The available amount of manganese also depends on the plant it self, as different species affect their environment in different ways. The research that has been made on the effects of cement plants on the environment shows similar results. The content of manganese in the air, in dust deposition and in soil is slightly higher around a cement plant. In most cases it’s not obvious that this is due to the cement production, as it is difficult to separate which contamination is due to the actual cement production and what is coming from other activities around the plant such as transports. There are also studies carried out in the same purpose that does not analyze the effects of manganese but of other metals. There is no research available on Swedish cement plants and nothing that specializes in manganese. In literature describing the process of cement manufacturing manganese is considered a non volatile compound that will be incorporated in the burnt clinker. Today the use of renewable fuel and raw material is increasing to lower carbon dioxide emissions and replace the fossil fuel used by the mineral industries. Limestone used as raw material contains significantly more manganese then the renewable fuel. Limestone contains manganese as manganese oxides which are not volatile in the cement manufacturing process, which means that no great emissions will occur. A very small amount of heavy metals will always evaporate but will be caught in the electro filters in the chimney. A certain amount of dust will also be emitted, how much varies greatly and depends on the type of process used. Emissions from industries and activities are regulated by Swedish law and the European Union. Manganese is often grouped together with other metals, for example Sb, As, Pb, Cr, Co, Cu, Ni and V, and the emission of the total amount of all these metals including manganese is limited. This can pose a problem for the development and use of renewable fuel and raw material for the mineral industries as manganese is present in sedimentary rocks in greater amounts then the other metals it is often grouped with

Modellering av inverkan av magnesium från alternativa råmaterial på Portland cementklinker kemi

The methods used in this thesis work were a combination of computational and modeling based laboratory experiments. Thermodynamic process modeling of the cement clinker process offers a tool for evaluating how changes in raw materials and process parameters affect the clinker quality. Work with finding suitable replacement raw materials involves investigating the chemical compatibility of potential alternative materials. Such replacement materials may be metallurgical slags, although there are some unsolved issues with the quantities of certain metals and particularly Mg in these materials. For predicting the formation of clinker mineral phases, cooling calculations are used in order to reproduce the temperature history in the full scale process. A chemistry model including a solid solution phase based on C2S and phosphate was developed along with the recommendation for continued work on clinker phases with solid solutions to include MgO. A thermodynamic database for phase chemistry calculations of clinkering reactions was created and evaluated. Suitable compounds and solution species were selected from the thermochemical database included in FactSage software. The extent and quality of the required thermodynamic data via available databases is generally satisfactory, except for certain properties of some of the main clinker phases. One example is the lack of a thermodynamic model for the alite solid solution. That is, the composition of the phase available in the database representing alite does not contain the minor elements Al, Fe and Mg. Therefore, it is difficult to predict the quantity and distribution of Mg in the clinker, with varying total content of MgO. Thus, one of the goals/objectives was to improve thethermodynamic model of alite as a solid solution of 3CaO-SiO2-xAl2O3-yFe2O3-zMgO. To achieve this, it was assumed that a mix of compounds with adjusted Henrian coefficients representing the solid solution clinker phase alite was in equilibrium with the clinker melt. The distribution of MgO was studied in synthetic clinker compositions with quantities ranging from 0.5 to 10 wt-%. Synthetic clinker mixes were heated to 1450°C and studied with Rietveld refinements of X-ray diffraction data and SEM-EDS analysis. In addition, the mechanisms of how slag and lime particles react facilitating the diffusion of MgO into the developing clinker melt and the formation of incipient belite were studied. The calculated results provide a good prediction of the quantities and composition of the clinker phases formed during heating and non-equilibrium cooling. The solubility of MgO in the clinker and the quantity of periclase formed is in fair agreement with published data. Thus, this thesis work shows that using a mix of compounds with adjusted activities in alite together with available standard thermodynamic data and the Scheil cooling method had good potential for evaluating alternative raw materials. Also, the work has identified weak points in the process modeling and suggest improvements to be made in future research work