96 research outputs found
Student Perceptions of Privacy in Learning Analytics: A Quantitative Study of Norwegian Students
No full textMasteroppgave i informasjonsvitenskapINFO390MASV-INF
Using SMS text messaging for teaching and data collection in the behavioral sciences
No full textRecent interest in university teaching has focused on interactivity in lectures and practical classes, and teachers in several fields have set up systems in which students can interact with the lecturer using mobile-phone-based SMS text messaging. This approach has particular potential in psychology, where students could use SMS messaging as a way of responding in simple psychology experiments or demonstrations. We describe a simple architecture for an SMS-based responding, using an SMS-to-HTTP message relay service, and a PHP/MySQL input-output handler. We describe briefly two experiments we have run using the system. The first experiment examined anchoring effects in an SMS-based auction. The second experiment examined delay discounting, with participants indicating their intertemporal preferences using SMS. Finally, we evaluate the feedback we obtained from students about the practical and conceptual issues surrounding text-message-based responding
Using Adobe Flash Lite on mobile phones for psychological research: reaction time measurement reliability and inter-device variability
No full textMobile telephones have significant potential for use in psychological research, possessing unique characteristics—not least their ubiquity—that may make them useful tools for psychologists. We examined whether it is possible to measure reaction times (RTs) accurately using Adobe Flash Lite on mobile phones. We ran simple and choice RT experiments on two widely available mobile phones, a Nokia 6110 Navigator and a Sony Ericsson W810i, using a wireless application protocol (WAP) connection to access the Internet from the devices. RTs were compared within subjects with those obtained using a Linux-based millisecond-accurate measurement system. Results show that measured RTs were significantly longer on mobile devices, and that overall RTs and distribution of RTs varied across device
Grain constraint and size effects in shape memory alloy microwires
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 142-147).Shape memory alloys exhibit interesting and useful properties, such as the shape memory effect and superelasticity. Among the many alloy families that have been shown to exhibit shape memory properties the ones based on copper are interesting because they are relatively inexpensive and show excellent properties when made as single crystals. However, the performance of these alloys is severely compromised by the introduction of grain boundaries, to the point where they are too poor for commercial applications. This thesis studies the mechanical properties of fine Cubased wires with a bamboo microstructure, i.e., where triple junctions are absent and grain boundaries run perpendicular to the wire axis. These microwires are not single crystals, but their microstructure is not as complex as that of polycrystals either: we call this new class of shape memory alloys oligocrystals. This thesis seeks to better understand the relationship between microstructure and properties in these alloys through a combination of mechanical testing, in situ experiments and modeling. First, in situ scanning electron microscopy, together with finite element modeling, is used to understand the role of grain constraint on the martensitic transformation. Grain constraints are observed to be much less severe in oligocrystalline wires as compared to polycrystals. Oligocrystalline microwires are then thermomechanically tested and shown to exhibit excellent properties that approach those of single crystals. Next, property evolution during cycling is investigated, revealing training effects as well as fatigue life and fracture. Finally, size effects in damping and transformation morphology are studied and it is shown that a transition from a many-domain to a single domain martensite morphology takes place when the wire diameter is decreased.by Stian Melhus Ueland.Ph.D
The darling conceptions of your time, or: why Galileo Galilei sings so sadly in the chorus
No full text"The darling conceptions of your time, or: why Galileo Galilei sings so sadly in the chorus" portrays conceptions that are either embedded in copyright law or connected to the debate of copyright versus file sharing. Conceptions such as property over intellectual phenomena, control over copies, theft, among others, are analysed and discussed in relation to the digital environment. The article does so by using the unusual grip of telling a story about the astronomer Galileo Galilei in the middle of a societal change of world-view, supported by the lyrics of a song throughout the article. The song is appropriately enough called "The darling conceptions of your time" and fills what the author calls a “meta-pedagogical” purpose by being released under a Creative Commons licence allowing it to be copied eternally, but never sold. The author is a lawyer, a ph d student in sociology of law at Lund university, and a musician
A Field Study of Reduced Axial Compressor Performance Deterioration through Online Washing and Air Intake Filtration Upgrade
No full textBackground
Oil and gas production at several North Sea offshore installations is limited by the gas turbine power available, and any deterioration in gas turbine performance directly affects production rates. Fouling in the compressor section of the gas turbines is the main cause of performance deterioration, and the fouling is removed by offline water wash, where the compressor performance is restored back to the baseline level. An offline wash requires the engine to stop (downtime), and it is therefore crucial to have as lengthy intervals as practically possible between offline washes to enhance production efficiency and the economy of the plant. In order to achieve lengthy intervals between offline washes, the deterioration rate must be as low as possible, by implementing the optimum combination of intake air filtration system and online water wash of the gas turbine compressor.
Objectives
Analyse gas turbine compressor deterioration mechanisms and water washing fundamentals in order to develop, validate and implement an optimum water washing system for offshore applications. In addition, analyse the effect of air intake filter system deterioration in order to develop, validate and implement optimum air intake solutions.
Research approach, activities
The basis for this work has been empirical data from eleven LM2500PE gas turbines at a North Sea offshore field. Testing and validation of online water wash at increased water rates were performed on the subject engines, as well as air intake filtration upgrades by increasing filter class and improving the filter housing design features. The PhD project work has also included onshore testing of a gas turbine in deteriorated condition, as well as gas turbine intake air filter testing in a test cell facility. The field work on this subject has spanned more than ten years and was initiated by the author prior to the PhD project.
Conclusions, contributions
An effective water wash of the axial compressor starts with an offline wash system that is capable of fully restoring the performance and baseline of the engine, i.e. restoring the recoverable deterioration (fouling). The non-recoverable deterioration rate (mechanical wear, increased tip clearance, etc.) is marginal compared with the recoverable deterioration rate. A typical figure for the recoverable deterioration rate is a 4 % drop in compressor efficiency over a 4-month operation period between offline washes, whereas the typical non-recoverable deterioration rate is only 0.5 % over 3 - 4 years (25,000 operating hours between gas generator overhaul). The main finding in this work is that a daily online wash at high flow rate is the key parameter for high effectiveness and a low deterioration rate, with a recommended water-to-air ratio for the LM2500PE of between 1.2 to 1.6 % (by mass).
An effective air intake filtration system in an offshore environment consists of two main components. An upstream vane separator that knocks out the large droplets (coalescer) followed by a downstream filter section that stops the smaller droplets. In addition, other key elements for an effective filtration system are: drainage system, water/air locks, holding frame for filter elements, anti-icing system and access doors/windows for inspection and maintenance. The main challenge for an offshore filtration system is to handle water droplets with airborne salt particles. Other solid particles (soot, sand, etc.) are not the main challenge offshore. However, the filter system must occasionally handle such particles. In foggy/high humidity conditions, it is particularly challenging for the filtration system to operate effectively due to deterioration of the filter performance. This work has tested filters at different filter grades, both offshore and in an onshore test cell facility. The main findings are that increasing the filter grade from M6 to F7 has proven to be effective, combined with a shorter filter change interval, prior to the point where filter deterioration is severe. In addition, a CFD study of the air intake system has been performed, which resulted in flow optimization in the field.
On the whole, the results of the optimized air intake filtration and online water wash at high flow rate have given longer operation intervals between offline washes and lower deterioration rates. The present standard offline wash interval is extended to six months, compared with two months in the past. The compressor efficiency deterioration rate is reduced to just 0.5 % over each 6-month operation period. This has a major impact on the production rates, production efficiency and economy of the plant. It entails lower fuel consumption and exhaust emissions and hence lower costs for fuel, CO2 and NOx taxes and reduced environmental impact.
In addition, procedures and algorithms for gas turbine compressor efficiency correction and air flow analysis have been developed in the project. The major contributions of this work are presented in six papers included in the appendices.
Proposed further work
The shift in performance curves on the compressor map from clean to deteriorated condition should be further studied, as well as the effect on velocity diagrams and Reynolds number. The sensitivity in engine parameters for compressor efficiency vs. air flow should be further studied
Older patients with colorectal cancer at Levanger Hospital 1980-2016
No full textKreft i tykk- og endetarm har blitt den vanligste kreftsykdommen i Norge med unntak av brystkreft for kvinner og prostatakreft for menn. Sykdommen rammer i hovedsak eldre mennesker og har en insidens-topp rundt 70 års alder. Andelen eldre har økt i Norge de siste tiårene og vil fortsette å øke i årene som kommer. Moderne medisinsk behandling bidrar til at vi lever lenger, forventet levealder stiger, og de eldste aldersgruppene utgjøres av en stadig større andel av befolkningen. I takt med denne utviklingen forventer vi et økende press på helsetjenestene.
Riktig behandling av pasienter med kreft i tykk- og endetarm er viktig for å tilby best mulig behandling på individ-nivå, og for optimal utnyttelse av helseressursene. Retningslinjer for utredning og behandling følger av Helsedirektoratets handlingsprogram og er bortsett fra enkelte unntak like på tvers av aldersgruppene. Dette til tross for at evidensen i stor grad er basert på kunnskaper om yngre pasienter. Eldre pasienter utelates ofte fra kliniske studier på tross av at det er viktige forskjeller mellom aldersgruppene. Kunnskaper om yngre pasienter ikke alltid er direkte overførbare til de eldre. Yngre pasienter utgjør generelt sett en mer homogen gruppe, mens det hos eldre pasienter er store individuelle forskjeller hva angår aldersassosierte faktorer som må hensyntas ved behandling av kreft.
Å tilby en best mulig, individ-tilpasset behandling er en av de største utfordringene ved behandling av eldre pasienter med kreftsykdom. Dagens standard har rom for forbedring. Seleksjonen til de ulike behandlingsformene baseres på kunnskaper om pasienten og pasientens sykdom. Den multimodale evalueringen av pasienter må favne bredere slik at våre beslutninger baseres på et større grunnlag. Prehabilitering før behandlingsstart og intensivert tverrfaglig oppfølging gjennom behandlingsforløpet kan bidra til at flere klarer å gjennomgå tiltenkt behandling, forebygge behandlingsassosierte komplikasjoner, og forbedre overlevelse.
I Studie 1 undersøkte vi trender i insidens og presentasjon av kreft i tykk- og endetarm ved Sykehuset Levanger for perioden 1980 til 2016. Basert på våre observasjoner beregnet vi den videre insidensutviklingen frem mot 2040. Våre funn viste at insidensen av kreft i tykk- og endetarm nært fordoblet seg gjennom observasjonsperioden, hovedsakelig grunnet primært preventive (livsstilsrelaterte) årsaker. Analysene våre indikerte at påvirkningen fra primært preventive årsaker har nådd et toppunkt. Sammenlignet med insidensnivået i siste del av studien forventer vi en økning på 70% frem mot 2040. Økningen vil hovedsakelig skyldes at befolkningen blir eldre, og være spesielt merkbar i aldersgruppen 80 år.
I Studie 2 undersøkte vi diagnostikk og behandling av pasientene med tykktarmskreft ved Sykehuset Levanger i perioden 1980 til 2016, med et spesielt søkelys på åttiåringene. Studien viste at insidensen av kreft i tykktarm hos åttiåringene mer enn fordoblet seg gjennom studieperioden. Åttiåringene som gjennomgikk kirurgisk behandling med kurativt siktemål, hadde lavere korttidsoverlevelse enn de yngre pasientene. Åttiåringene som overlevde de første nitti dagene etter kirurgi, hadde like god relativ langtidsoverlevelse som de yngre pasientene. Den relative andelen av åttiåringer som ble behandlet med kirurgi økte gjennom observasjonstiden. Tiltak som forbedrer korttidsoverlevelsen, vil være nøkkelen til å forbedre langtidsoverlevelsen hos åttiåringer som blir operert med kurativt siktemål i fremtiden.
I Studie 3 undersøkte vi behandling av pasientene med endetarmskreft ved Sykehuset Levanger i perioden 1980 til 2016, med et spesielt søkelys på pasientene ≥80 år. Våre resultater viste at pasientene ≥80 år hadde mindre sjanse for å bli behandlet med kurativt siktemål sammenlignet med de yngre pasientene, på tross av like sykdomsstadier ved diagnosetidspunktet. Det var generelt en høy komplikasjonsrate ved stor kirurgi for endetarmskreft, og pasientene ≥80 år hadde mer alvorlige komplikasjoner enn de yngre pasientene. Pasientene ≥80 år som gjennomgikk kirurgisk behandling med kurativt siktemål hadde lik relativ langtidsoverlevelse som de yngre pasientene
How incidental values from the environment affect decisions about money, risk, and delay
No full textHow different are £0.50 and £1.50, or "a small chance" and "a good chance", or "three months" and "nine months"? Our experiments show that people behave as if these differences alter after incidental everyday experiences. Preference for a £1.50 lottery rather than a £0.50 lottery was stronger after exposure to intermediate supermarket prices. Preference for "a good chance" of winning rather than "a small chance" was stronger after predicting intermediate probabilities of rain. Preference for consumption in "three month" rather than "nine months" was stronger after planning for an intermediate birthday. These fluctuations offer a direct challenge to economic accounts which translate monies, risks, and delays into subjective equivalents by stable functions. The decision by sampling model, in which subjective values are rank positions constructed from comparisons with samples of monies, probabilities, or delays, predicts these effects and indicates a primary role for sampling in decision making
Some observations and suggestions about the Rural China Education Foundation library programs at two rural sites
No full textThis is a brief report on visits by the author to two Rural China Education Foundation sites in rural China, Shanxi and Shandong provinces, in 2008. I briefly describe the school libraries that the organization has established, and provide a number of advice for how their operation can be improved
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