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Now showing items 567-579 of 579
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Kruglikov, Boris Serafimovich; Matveev, VS (Journal article; Tidsskriftartikkel; Peer reviewed, 2006)[+][-]
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Grujic, Katarina; Hole, JP; Wilkinson, JS; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2005)[+][-]
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Hall, Chris; Xu, X; Manson, A.H.; Meek, Chris; Chshyolkova, Tatyana; Drummond, J. R.; Riggin, D.; Hibbins, RE (Journal article; Tidsskriftartikkel; Peer reviewed, 2009)[+][-]
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Kvitberg, Jill-Iren Karlsen (Master thesis; Mastergradsoppgave, 15-Sep-2008)[+][-]
Abstract: Varmeterapi (hypertermi) er en ny behandlingsmetode for krefttyper som ligger overfladisk plassert i kroppen. Prinsippet består i å varme opp vev til en temperatur på 42-45 ̊C, noe som øker raten for celledød i vevet. En multilags likeformet applikator er utviklet spesielt for dette formålet. En av bestanddelene i denne applikatoren er vannbolusen. Dens hensikt er å sørge for kontrollert temperatur på pasientens hud under oppvarmningen for å forhindre skader relatert til varme. Hensikten med oppgaven er å avdekke begrensninger i bolusen som brukes klinisk i dag. Dette gjøres med forsøk på en eksperimentell laboratoriemodell. Det gjøres en analyse av bolusens termo-fluidale egenskaper gjennom analyse av videosekvenser hvor kontrastvæske andvendes. Dette skal korreleres mot punkttemperaturmålinger basert på fineroptiske sensorer. Analysen gjennomføres for varierende volumflow og vanntemperaturer. Bolusen har lav effektivitet. Det er hovedsakelig dårlig distribusjon av vann som forårsaker dette. Flere vanninntak og/eller annen utnyttelse av slangene som distribuerer vann i bolus kunne bidratt til å bedre dette. dette må imidlertid ses i sammenheng med hvorvidt bolusen skal brukes horisontalt eller vertikalt på en pasient, da vanngjennomstrømningen i bolus påvirkes av dette. Effektiviteten til bolus øker imidlertid med økende volumflow. For de høyeste volumflowene tested erdet imidlertid ikke forskjellene store, og en flow på 0.9 lpm har tilnærmet lik egenskap som en volumflow på 1.5 lpm. I forhold til valg av temperatur i bolus må det taes hensyn til varmeoverføring fra huden. Medier som er i kontakt med bolus påvirker temperaturen i betydelig grad. Resultatene fra forsøkene er fra fiberoptiske temperatursensorer og en videokamera. Disse resultatene er så videreforedlet gjennom MATLAB. URI: http://hdl.handle.net/10037/1774 File(s) in this item: 1
thesis.pdf (22.17Mb) -
Kvalnes, Aage; Renesse, Robbert van; Johansen, Dag; Arnesen, Audun (Research report; Forskningsrapport, 13-Jun-2003)[+][-]
Abstract: Vortex is a new multiprocessor operating system that is entirely event-driven. The Vortex kernel, as well as its applications, are structured as stagesthat communicate through event passing. Each stage is a small finite state machine. The event architecture is efficient and allows Vortex to balance load across the processors automatically. Vortex uses an Event Scheduling Tree (EST) on each CPU. An EST is a tree of event queues, where each event queue can be instantiated with its own scheduling policy. The EST mechanism unifies all CPU and I/O scheduling and allows for a wide variety of scheduling policies including weighted performance isolation between applications. The paper shows how a high-performance web server can be supported on Vortex. Compared to running the same web server on Linux on the same hardware, Vortex can sustain up to 80% higher throughput. Experiments with running multiple web servers on Vortex show that we can precisely divide resources between the web servers at low overheads. Microbenchmarks break down the costs of these overheads. URI: http://hdl.handle.net/10037/367 File(s) in this item: 1
report.pdf (337.3Kb) -
Nilsen, Arild (Master thesis; Mastergradsoppgave, Nov-2011)[+][-]
Abstract: To achieve low overhead, traditional cluster monitoring systems sample data at low frequencies and with coarse granularity. However, interactive monitoring requires frequent (up to 60 Hz) sampling of fine-grained data and visualization tools that can explore and display data in near real-time. This makes traditional cluster monitoring systems unsuited for interactive monitoring of distributed cluster applications, as they fail to capture short-duration events, making understanding the performance relationship between processes on the same or different nodes difficult. To address this issue, WallMon was developed, a tool for interactive visual exploration of performance behaviors in distributed systems. For gathering of data, WallMon is centered around an abstraction of collectors and handlers; collectors gathers data of interest, such as CPU and memory usage, and forwards it to handlers in a push-based fashion, while handlers take action upon the data. WallMon captures and visualizes data for every process on every node, as well as overall node statistics. Data is visualized using a technique inspired by the concept of information flocking. WallMon's design is based on the client-server model, and it is extensible through a module system that encapsulates functionality specific to monitoring (collectors) and visualization (handlers). A set of experiments have been carried out on a cluster of 29 nodes with 180 processes per node. Performance results show 7% (of 100) CPU usage at 64 Hz sampling rate when performing process-level monitoring with WallMon. Using WallMon's interactive visualization, we have observed interesting patterns in different parallel and distributed systems, such as unexpected ratio of user- and kernel-level execution among processes in a particular distributed system. URI: http://hdl.handle.net/10037/3991 File(s) in this item: 2
cdrom.zip (489.1Mb)thesis.pdf (26.17Mb) -
Nguyen, Hung Thanh (Doctoral thesis; Doktorgradsavhandling, 17-Jun-2011)[+][-]
Abstract: For the mass transfer case (the absorption of moisture-water into concrete), the water content in concrete has a significant impact on its mechanical properties. Moisture transport in porous media, for example, plays an important role in the degradation of building materials such as mortars and concrete. LWE ignores the complex pore structure and network, typically found in cement materials. Many earlier research works has shown clearly that complex pores structure of concrete, strongly impedes the water penetration. Following this line, we believe also that the changing of pore structure may impose a strong effect on the water capillary suction. Description: Paper 3 of the thesis is not available in Munin due to publishers' restrioction:
3. Hung Thanh Nguyen, Frank Melandsø and Stefan Jacobsen: 'Time dependent durface heat transfer in light weight aggregate cement based materials', Engineering, 2010, 2, 307-317. Available at http://dx.doi.org/10.4236/eng.2010.25040URI: http://hdl.handle.net/10037/3443 File(s) in this item: 1
thesis.pdf (2.409Mb) -
Foss, Marianne (Doctoral thesis; Doktorgradsavhandling, 28-Feb-2001)[+][-]
Abstract: Virkninga av å ha et bølgedempende overflatemateriale i ei havoverflate er studert, med særlig vekt på betydninga av strålingstrykket (-stresset) eller bølgetrykket fra et innfallende, udempet bølgefelt. Det er et teoretisk studium av den dynamiske prosess som foregår når udempede overflatebølger propagerer inn i et område med bølgedempende overflatesjikt, i lys av det bølgetrykk bølgene øver på dette sjiktet. En hydrodynamisk modell som beskriver prosessen er utviklet. Perturbasjonsteori og ikke-lineær analyse er anvendt for å løse de grunnleggende bevaringsligningene for moment (Navier-Stokes' ligninger) og masse, innenfor en væskebeskrivelse hvor man "følger med i" bevegelsen til de enkelte væskepartikler (Lagrange-beskrivelse) - til forskjell fra den mer vanlige feltbeskrivelse av væskebevegelse (Euler-beskrivelse). Modellen er anvendt på to typer overflatemateriale: i) Mono-molekylær oljefilm, hvor tangentialstresset i filmen er viktig, og ii) et overflatelag av is-sørpe, hvor den økte viskositeten er avgjørende. En del dynamiske implikasjoner er utledet ved hjelp av analytiske beregninger: I tilfellet oljefilm vil det oppstå et midlere tangentielt overflatestress i filmen, og det er vist at dette kan uttrykkes ved en formel som er meget lett å interpretere fysisk. For is-sørpe viser beregningene at det vil oppstå sirkulasjon i sørpa, noe som også er påvist eksperimentelt av andre tidligere. Omfattende og tidkrevende analytiske beregninger har vært nødvendig. Det viste seg etter hvert at de svært uoversiktlige uttrykk som inngår, lar seg skrive på en meget kompakt og symmetrisk form som gjør framstillinga "lesbar". Resultatene er videre forenlige med resultater fra mye enklere og intuitive modeller, noe som bekrefter gyldigheten av de enkle modellene. Dette er viktig med tanke på anvendelser. URI: http://hdl.handle.net/10037/283 File(s) in this item: 1
thesis.pdf (3.289Mb) -
Britz, Thomas; Johnsen, Trygve; Mayhew, Dillon; Shiromoto, Keisuke (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: We present several fundamental duality theorems for matroids and more general combinatorial structures. As a special case, these results show that the maximal cardinalities of fixed-ranked sets of a matroid determine the corresponding maximal cardinalities of the dual matroid. Our main results are applied to perfect matroid designs, graphs, transversals, and linear codes over division rings, in each case yielding a duality theorem for the respective class of objects. URI: http://hdl.handle.net/10037/4862 File(s) in this item: 1
article.pdf (158.2Kb) -
Hall, Chris; Manson, A.H.; Meek, C.; Chshyolkova, T.; McLandress, C.; Avery, S.K.; Fritts, D.C.; Hocking, W.K.; Igarashi, K.; MacDougall, J.W.; Murayama, Y.; Riggin, D.C.; Thorsen, D.; Vincent, R.A. (Journal article; Peer reviewed, 20-Oct-2006)[+][-]
Abstract: Following earlier comparisons using the Canadian Middle Atmosphere Model (CMAM, without interactive chemistry), the dynamical characteristics of the model are assessed with interactive chemistry activated. Time-sequences of temperatures and winds at Tromsø (70° N) show that the model has more frequent and earlier stratospheric winter warmings than typically observed. Wavelets at mesospheric heights (76, 85 km) and from equator to polar regions show that CMAM tides are generally larger, but planetary waves (PW) smaller, than medium frequency (MF) radar-derived values. Tides modelled for eight geographic locations during the four seasons are not strikingly different from the earlier CMAM experiment; although monthly data now allow these detailed seasonal variations (local combinations of migrating and non-migrating components) within the mesosphere (circa 50–80 km) to be demonstrated for the first time. The dominant semi-diurnal tide of middle latitudes is, as in the earlier papers, quite well realized in CMAM. Regarding the diurnal tide, it is shown here and in an earlier study by one of the authors, that the main characteristics of the diurnal tide at low latitudes (where the S (1,1) mode dominates) are well captured by the model. However, in this experiment there are some other unobserved features for the diurnal tide, which are quite similar to those noted in the earlier CMAM experiment: low latitude amplitudes are larger than observed at 82 km, and middle latitudes feature an unobserved low altitude (73 km) summer maximum. Phases, especially at low and middle (circa 42° N) latitudes, do not match observations well. Mesospheric seasonal tidal variations available from the CUJO (Canada U.S.\ Japan Opportunity) radar (MFR) network (sites 40–45° N) reveal interesting longitudinal differences between the CMAM and the MFR observations. In addition, model and observations differ in the character of the vertical phase variations at each network-location. Finally, the seasonal variations of planetary wave (PW) activity available from CMAM and the MFR show quite good agreement, apart from the amplitude differences (smaller in CMAM above 70 km). A major difference for the 16-d PW is that CMAM shows large amplitudes before the winter solstice; and for the 2-d PW, while both CMAM and MFR show summer and winter activity, the observed summer mesopause and winter mesospheric wave activities are stronger and more extended in height. Models such as CMAM, operated without data-assimilation, are now able to provide increasingly realistic climatologies of middle atmosphere tides and PW activity. Differences do exist however, and so discussion of the various factors affecting tidal and PW characteristics in atmospheres, modelled and observed, is provided. Other diagnostics of model-characteristics and of future desirable model experiments are suggested. URI: http://hdl.handle.net/10037/586 File(s) in this item: 1
article.pdf (3.988Mb) -
Solheim, Jan Erik; Hernanza, M.; González-Riestra, R.; Wamsteker, W.; Shustov, B.; Barstow, M.; Brosch, N.; Fu-Zhen, C.; Dennefeld, M.; Dopita, M.; Gómez de Castro, A.I.; Kappelmannc, N.l.; Pagano, I.; Sahade, J.; Haubold, H.; Solheim, J.-E.; Martínezc, P. (Journal article; Tidsskriftartikkel, 5-Nov-2002)[+][-]
Abstract: We summarize the capabilities of the World Space Observatory (UV) Project (WSO/UV). An example of the importance of this project (with a planned launch date of 2007/8) for the study of Novae is given. URI: http://hdl.handle.net/10037/2037 File(s) in this item: 1
article.pdf (242.1Kb) -
Jenssen, Robert (Conference object; Konferansebidrag, 02-Sep-2010)[+][-]
Description: Innlegg på seminaret "Science - who cares?" ved NT-fak, Universitetet i Tromsø. URI: http://hdl.handle.net/10037/2696 File(s) in this item: 1
article.pdf (7.928Mb) -
Lejon, Tore; Gozhina, Olga Vladimirovna; Khrustalev, Victor N. (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: The molecule of the title compound, C16H21BO2, comprises a chiral fused tricyclic system containing five-membered (1,3,2-dioxaborolane), six-membered (cyclohexane) and four-membered (cyclobutane) rings. The 1,3,2-dioxaborolane ring is almost planar (r.m.s. deviation = 0.035 Å), and the syn H and Me substituents at this ring are in an eclipsed conformation. The cyclohexane and cyclobutane rings adopt sofa and butterfly conformations, respectively. The B atom has a trigonal-planar configuration (sum of the bond angles = 360.0°). The phenyl ring is practically coplanar with the 1,3,2-dioxaborolane ring [dihedral angle between the ring planes = 1.96 (8)°]. The absolute structure was determined from the known configuration of (+)-pinanediol which was used in the synthesis. In the crystal, weak C-H...[pi](Ph) interactions occur. URI: http://hdl.handle.net/10037/4635 File(s) in this item: 1
article.pdf (396.8Kb)
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