<p>Detta examensarbete undersöker om och hur man med hjälp av filskillnader kan effektivisera uppdateringar av datorspel. Flertalet olika tester med deltaenkodning har utförts, detta på olika versioner av filer från kommersiella och aktuella spel. Bland annat har försöken med deltaenkodning jämförts med de officiella speluppdateringarna, och med vanlig komprimering av de aktuella filerna. Resultaten visar att användning av deltaenkodning på de filer som ändrats mellan spelens versioner kan vara mycket effektivare och ta mindre plats än de officiella speluppdateringarna.</p>

<p>This master thesis deals with steel girders subjected to patch loading caused by concentrated moments. There exist no good methods to calculate by hand the ultimate resistance for this load case. In “tunnplåtshandboken”, (Handbook for sheet metal, which is published by SSAB), one calculation method is presented. It’s however fairly difficult to use, because of many calculation steps and many graphs. This study concentrates on how to calculate the resistance for this load case in a better way. The load case arises for example when a small steel plate (attachment) is welded to the flange above the web of a girder and the attachment is pulled in a direction parallel to the beam. It’s possible view the load as two components, a moment and a horizontal load. The moment will push the attachment into the girder and finally yielding in combination with web buckling will govern the ultimate resistance. In this report, only the moment part of the load is studied.</p><p>This study was made in three steps. First an FE-model was built. This model was verified against physical tests on patch loading from a force acting perpendicular to the beam axis. This approach was taken because no tests were found for the load case with a local moment. As step number two the FE-model was numerically adjusted to work for tests with patch loading caused by a local moment. A number of experiments were made, for which two parameters were varied, the thickness of the web and the length of the attachment. The loaded attachment was made very stiff, because it should not be deformed in order to simulate a sharp concentrated moment. In the last step a hand calculation model was developed for the investigated load case.</p><p>The FE-model that was created for comparison to the physical experiments gave resistances 10 % below the resistances, from the physical tests. This was mainly due to the sensitivity of the girder to initial imperfections and that the most severe buckling mode was used in the modeling of the imperfections.</p><p>The handcalculation model was developed to imitate the one for patch loading in EN 1993-1- 5 (EC3), because it may then work as an addition to EC3. The model was developed in three steps: yield resistance, critical elastic buckling load and the resistance function. The model for yield resistance is analytical and has a form equivalent to the one in EC3. The expressions for the critical elastic buckling load were taken as simple as possible, since they are the main area of this study. The method essentially uses the same equations as EC3 except from two small changes. The results are on the safe side but the safety margin increases when the length of the loaded attachment decreases and the slenderness of the web panel increase. Consequently formulas for calculating the critical load may be improved. The chosen reduction function was slightly increased compared to the function in EC3 but the results will still have a good safety margin. The complete model gives results where the safety margin increases as the length of the loaded attachment decreases. The calculation model was designed to be easy to use. In comparison to the FE-analysis, all the tested beams except a few with low slenderness gave results on the safe side.</p> / <p>Detta examensarbete behandlar stålbalkar utsatta för lokal intryckning orsakade av en lokal momentbelastning. För lastfallet finns ännu inga bra handräkningsmetoder, i plåthandboken som ges ut av SSAB finns en beräkningsmetod presenterad. Den är väldigt krånglig med många beräkningssteg och diagram. Denna studie är inriktad på att utreda hur man kan räkna på belastningsfallet på ett enklare och bättre sätt. Lastfallet uppkommer t.ex. då en lastögla svetsas till flänsen rakt över livet på en balk. Om lastöglan dras parallellt med balkens riktning så kan belastningen ses som två komponenter, ett moment och en horisontalkraft. Momentet kommer att trycka in lastöglan i balken och till slut blir det ett brott p.g.a. en blandning av att materialet flyter och att livet bucklar. I den här rapporten behandlas bara momentdelen av lasten.</p><p>Studien är gjord i tre steg. Först byggdes en FE-modell i Abaqus. Denna modell verifierades mot fysiska försök på lokal intryckning från en vertikal kraft, eftersom inga försök hittades på intryckning av ett lokalt moment. Som steg nummer två anpassades FE-modellen till försök med lokal intryckning från ett moment. Ett antal experiment gjordes med variation av två parametrar, livplåtens tjocklek och lastöglans längd. Lastöglan var väldigt styv eftersom den bara skulle skapa momentbelastningen. Sista steget var att utifrån resultaten ta fram en beräkningsmodell för lastfallet.</p><p>FE-modellen som skapades för testerna visade sig ge bärförmågor ca 10% under bärförmågan från de fysiska försöken. Detta berodde mycket på att balken var känslig för hur initialimperfektionerna såg ut och att första bucklingsmodens form användes vid modelleringen av de geometriska imperfektionerna.</p><p>Beräkningsmodellen utvecklades så att den skulle efterlikna den som gäller för lokal intryckning från vertikal last i EN 1993-1-5. Detta för att modellen skulle kunna användas som ett tillägg till EK3. Modellen utvecklades i tre delar, flytbärförmågan, kritiska bucklingslasten och reduktionsfaktorn för buckling. Modellen för flytbärförmågan togs fram analytiskt och fick en form som efterliknar den i EK3. Beräkningsmetoden för den kritiska bucklingslasten använder sig i princip av formlerna i EK3 förutom två små ändringar. Reduktionsfunktionen som valdes är en liten ökning av funktionen i EK3 men resultaten ligger ändå med bra marginal på säkra sidan. Den kompletta beräkningsmodellen ger resultat där säkerhetsmarginalen ökar vid minskande längd på lastöglan. Den har utformats så att den är lätt att använda och vid jämförelse med FE-försök gav beräkningsmodellen resultat på säkra sidan för alla balkar förutom några få av balkarna med låg slankhet. </p>

Les composants aéronautiques sont soumis en service à des sollicitations mécaniques donnant lieu à des états de contraintes multiaxiaux et à amplitude variable provocant un phénomène d'endommagement par fatigue. Une alternative à la réparation de ces structures consiste à les renforcer préventivement, avant que la fissure ne soit apparue. Le contexte de ce travail s'inscrit donc dans le cadre du renforcement préventif de structures par patchs composites afin de retarder l'apparition de fissures. Des essais de fatigue sur éprouvettes en aluminium 2024-T3 renforcées sont menés pour observer et quantifier l'aspect bénéfique du renforcement en termes de durée de vie. Une méthodologie de dimensionnement en fatigue sous sollicitations de service est également proposée. Parallèlement, la mesure d'échauffement par caméra infrarouge est utilisée pour aider à comprendre le processus d'endommagement et de cumul de dommage propres à cet alliage.

Des patchs en matériaux composites sont classiquement utilisés dans l'aéronautique pour la réparation des structures métalliques présentant des dommages de<br />type fissures, criques ou impacts. Une alternative à la réparation de ces structures consiste à les renforcer préventivement, avant que les défauts n'apparaissent. Le<br />contexte de ce travail est celui de la maintenance préventive de structures métalliques aéronautiques par renforts composites, dans le but de retarder l'apparition ou la propagation de fissures.<br />La conception des renforts nécessite l'utilisation d'outils spécialisés pour définir les caractéristiques optimales du patch : géométrie, nombre de plis unidirectionnels,<br />orientation des plis les uns par rapport aux autres, positionnement autour de la zone à soulager... Pour cela, un programme d'optimisation de patchs par algorithme<br />génétique a été écrit. Il est couplé à un logiciel de calcul par éléments finis : Ansys.<br />L'algorithme génétique mis en oeuvre a permis de déterminer des caractéristiques de patchs dont la géométrie extérieure est définie par une courbe spline fermée, ceci afin de réduire de manière optimale les contraintes mécaniques dans une zone donnée, et<br />ce pour différents types de sollicitations.<br />De nombreuses d´efaillances des assemblages collés patch/substrat sont liées à des concentrations de contraintes dans la colle dues à l'existence d'une zone de<br />transfert progressif d'effort du substrat vers le patch. Des approches unidirectionnelles du transfert d'effort sont classiquement utilisées dans la littérature. Elles ne<br />tiennent cependant pas compte d'effets bidimensionnels comme la différence des coefficients de Poisson qui peut exister entre le substrat et le composite. A partir des<br />équations d'équilibre, des modèles analytique et numérique bidimensionnels ont donc été développés. Des phénomènes de couplages bidimensionnels ont ainsi bien été mis en évidence.<br />Parallèlement, des essais de traction uniaxiale ont été réalisés sur des éprouvettes en aluminium renforcées par des patchs en carbone/époxyde. La méthode de la grille a été utilisée pour mesurer des champs cinématiques en surface du patch composite.<br />Cette méthode a permis d'étudier expérimentalement le transfert des efforts entre le substrat et le renfort suivant les deux dimensions du problème et de comparer les résultats obtenus avec les différents modèles développés au préalable.

The polarization performance of two types of commercial galvanic point anodes for protection of reinforced steel around patch repairs was investigated. Experiments included measurement of the polarization history of the anode under constant current impressed by galvanostatic circuits and in reinforced concrete slabs. The tests revealed, for both types of anodes, a potential-current function (PF) indicating relatively little anodic polarization from an open circuit potential at low current levels, followed by an abrupt increase in potential as the current approached an apparent terminal value. Aging of the anodes was manifested by a continually decreasing current output in the concrete tests, and by increasingly more positive potentials in the galvanostatic tests. Those changes reflected an evolution of the PF generally toward more positive open circuit potentials and, more importantly, to the onset of elevated polarized potentials at increasingly lower current levels. There was considerable variability among the performance of replicate units of a given anode type. Modest to poor steel polarization levels were achieved in the test yard slabs. Modeling of a generic patch configuration was implemented with a one-dimensional approximation. The model calculated the throwing distance that could be achieved by a given number of anodes per unit perimeter of the patch, concrete thickness, concrete resistivity, amount of steel and amount of polarization needed for cathodic prevention. The model projections and aging information suggest that anode performance in likely application scenarios may seriously degrade after only a few years of operation, even if a relatively optimistic 100 mV corrosion prevention criterion were assumed. Less conservative criteria have been proposed in the literature but are yet to be substantiated. Other investigations suggest a significantly more conservative corrosion prevention may apply instead. The latter case would question the ability of the point anodes to provide adequate corrosion prevention.

The Along-Track Reef-Imaging System (ATRIS) is a vessel-mounted, digital camera, depth sounder and Global Positioning System (GPS) package that facilitates the rapid capture of underwater images in shallow-water benthic environments. This technology has the potential to collect ecologically significant data, particularly in benthic habitats less than 10 m in depth, with better location referencing and in less time than is required for surveys carried out by Scuba divers. In October 2004, ATRIS was tested coincidently with SCUBA-assisted video along transects on five patch reefs in Biscayne National Park. Images from both data sets were subsampled, viewed, and benthic cover under random points were identified and counted. Digital-still images of reef benthos collected by ATRIS were of higher quality than SCUBA-acquired video imagery, allowing more reliable classification of benthos. “Substrate”, which included areas of hard-ground, sand or rubble, was the most frequently identified benthic category (43%), followed by octocoral (21%), unidentifiable (19%), and macroalgae (12%). Total stony coral cover averaged less than 5%. ATRIS-acquired benthic-cover data were compared with rugosity data derived from the Experimental Advanced Airborne Research Lidar (EAARL), revealing no strong correlations, probably because much of the hard substrate patch reef topography was created by corals that have died in the past few decades. ATRIS, diver-acquired data, and EAARL provide different scales of information, all of which can be valuable tools for assessing and managing coral reefs.

The focus of this dissertation is on the development and circuit modeling of planar series-fed, linear- and circular-polarized microstrip aperture-coupled antennas and N-element arrays operating in C-band. These arrays were designed to be used as part of airborne or land-based frequency-hopped communication systems. One of the main objectives of this work was to maintain a constant beam angle over the frequency band of operation. In order to achieve constant beam pointing versus frequency, an anti-symmetric series-fed approach using lumped-element circuit models was developed. This series feed architecture also balances the power radiated by each element in the N-element arrays. The proposed series-fed approach was used in the development of four-element series-fed aperture-coupled arrays with 15% 10 dB impedance bandwidth centered at 5 GHz and a gain of 11.5 dB, to construct an omni-directional radiator. Omni-directional radiators with pattern frequency stability are desired in a multitude of applications; from defense in tactical communications, information gathering, and detection of signal of interest to being part of sensors in medical applications. A hexagonal assembly of six series-fed microstrip aperture-coupled four-element arrays was used to achieve the omni-directional radiation with 0.6 dB peak to peak difference across 360˚ broadside pattern and 0.6 dB gain variation at the specific azimuth angle across 15% impedance bandwidth. Given that each of these six arrays can be individually controlled, this configuration allows for individual pattern control and reconfiguration of the omni-directional pattern with increased gain at specific azimuth angles and the ability to form a directional pattern by employing a fewer number of arrays. Incorporating a beam-forming network or power distribution network is also possible. Wide 3 dB circular polarization (CP) bandwidth was achieved without external couplers and via only a single feed with a unique Z-slot aperture-coupled microstrip antenna. A single RHCP Z-slot aperture-coupled antenna has ∼10% CP and 10 dB impedance bandwidth. The series-fed network consisting of lumped elements, open-circuited stubs and transmission lines was subsequently developed to maintain more than 5% CP and 10% 10 dB impedance bandwidth in the series-fed four-element Z-slot aperture-coupled CP array that could also be used for-omni-directional radiation.

A novel approach to miniaturizing an 802.11b WLAN card using folded-flex ultra-thin substrates is presented. A 73 percent reduction in size was realized using hybrid circuits on FR4 and polyimide. There is even more potential for further reduction if more copper layers are used. The miniaturized 802.11b WLAN cards were used to design 802.11b wireless sensor nodes. A research test-bed was setup to study how 802.11b networked sensor nodes could operate in the field. There are many applications for such sensor networks like habitat monitoring, object tracking, seismic detection, military surveillance, or fire detection to name a few. This investigation focuses on the requirements, design, and performance of a miniaturized 802.11b wireless LAN sensor node that is reliable, can be deployed in large-scale, and has the endurance long-lived for surveillance applications. An aperture coupled microstrip antenna is investigated for 2.44 GHz wireless local area networks (WLAN) which has the advantages of being low-profile and compact. The most important parameters for antenna optimization have been determined through extensive simulation using Ansoft's HFSS and experimental verification. As a result, an omnidirectional antenna with a size of 36.2 mm x 32 mm x 4.75 mm has been realized using Rogers 5880 duroid (permittivity = 2.20 ; loss tangent = 0.0004) with 4.4 dBi of gain, > 80 MHz, and a return loss > -32 dB. These types of performance characteristics make the antenna highly desirable for both 802.11b and Bluetooth applications.

Results from archaeological survey provide new insights into the origins of variation among the prehistoric Native American societies that occupied the Chickasawhatchee Swamp of southwestern Georgia. Through macroregional comparison, these insights are broadly applicable to the Eastern Woodlands societies that existed across the southeastern U.S. between A.D. 150 and 1600. Theoretical frameworks concerning landscape ecology, inter-regional exchange, and agency and structure provide the organizing structure for a multi-scalar view of change that contradicts earlier models.Within the Chickasawhatchee Swamp, survey, mapping, and excavation data present a complex regional settlement system. Within the swamp, a few large settlements were occupied for the long-term, in spite of the absence of monumental architecture. Smaller surrounding sites were periodically abandoned. At the swamp's edge, several subregions were organized around civic-ceremonial mound sites. At these edges, mound sites and surrounding subregions were abandoned simultaneously. Instead of being driven by changes in political complexity, residential mobility cycles were consistent through time and related to the region's heterogeneous landscape.Macroregional spatial data comparing mound locations through time support data from the Chickasawhatchee Swamp and confirm hypotheses relating mound construction and transitional landscapes. New data emphasize continuity in inter-regional exchange networks and contradict earlier views in which the emergence of hierarchical political structures were a transformational process that fundamentally altered Eastern Woodlands political economies. Temporal continuity and spatial variation are instead most evident.

Background: Sex and stress steroids are metabolized to 3a-hydroxy-pregnane-steroid metabolites such as allopregnanolone (Allo) and tetrahydrodeoxycorticosterone (THDOC). Allo and THDOC are neuroactive steroids that are metabolized in the brain and act in brain as potent positive GABAA receptor function modulators. Allo as well as THDOC levels increase during stress. Allo has been associated with a number of symptoms and malfunctions such as impaired memory function and negative mood symptoms in a subgroup of individuals both for animals and humans. Pregnane steroids with 3b-hydroxy-configuration (3b-steroids) have been shown to reduce the Allo enhanced GABA effect. Aims: The aims for the present thesis were to investigate the effect of 3b-steroids on the GABA mediated GABAA receptor function in presence of positive GABAA receptor modulators. Further, the regional variances between the 3b-steroids as well as the mechanism of the effect were studied. Finally, the effect of stress steroid metabolites on the GABAA receptor function was investigated. Results: 3b-OH-5a-pregnane-20-one reduced the Allo enhanced GABA mediated chloride ion uptake into cortical microsacs. The 3b-isomer reduced the efficacy of Allo without shift the concentration response curve. It is therefore suggested that the 3b-isomer has a non-competitive effect. Further, it was shown that the 3b-isomer reduced the Allo effect in a selective way since the 3b-isomer did not interact with other positive modulators or with GABA itself. Five tested 3b-steroids reduced the Allo enhanced GABA mediated chloride ion uptake in cerebral cortex and hippocampus as well as the Allo prolongation on spontaneous inhibitory postsynaptic currents (sIPSCs) in preoptic nucleus. In cerebellum on the other hand the 3b-steroids showed to have weaker or no effect compared to the other tested regions. Interestingly, in absence of Allo, two of the 3b-steroids positively modulated the GABA stimulated GABAA receptor function. In absence of Allo, 5b-pregnane-3b,20(R)-diol increased the desensitization rate of current response. In contrast to the reducing effect on the Allo induced prolongation on sIPSCs, the effect of the 3b-steroid on GABA application, was not altered in presence of Allo. The mechanism of the 3b-steroid is therefore suggested being desensitization dependent in contrast to Allo, which has been suggested to decrease the GABA unbinding rate. In contrast to the enhanced effect of Allo, glucocorticoid metabolites reduced the GABA mediated chloride ion uptake in a concentration dependent way. The results in present thesis indicate that both sex and stress steroid metabolites interact with the GABAA receptor function. The knowledge that diversity of endogenous steroids interact with the GABAA receptor function is of importance for further understanding of different sex and stress steroid related symptoms and syndromes.