Finding Regressions in Projects under Version Control Systems

Version Control Systems (VCS) are frequently used to support development of large-scale software projects. A typical VCS repository of a large project can contain various intertwined branches consisting of a large number of commits. If some kind of unwanted behaviour (e.g. a bug in the code) is found in the project, it is desirable to find the commit that introduced it. Such commit is called a regression point. There are two main issues regarding the regression points. First, detecting whether the project after a certain commit is correct can be very expensive as it may include large-scale testing and/or some other forms of verification. It is thus desirable to minimise the number of such queries. Second, there can be several regression points preceding the actual commit; perhaps a bug was introduced in a certain commit, inadvertently fixed several commits later, and then reintroduced in a yet later commit. In order to fix the actual commit it is usually desirable to find the latest regression point. The currently used distributed VCS contain methods for regression identification, see e.g. the git bisect tool. In this paper, we present a new regression identification algorithm that outperforms the current tools by decreasing the number of validity queries. At the same time, our algorithm tends to find the latest regression points which is a feature that is missing in the state-of-the-art algorithms. The paper provides an experimental evaluation of the proposed algorithm and compares it to the state-of-the-art tool git bisect on a real data set

Streaming potential - qualification of method and investigating the impact of brine in sandstone core plugs

Master's thesis in Petroleum engineeringStreaming potential is an electrokinetic phenomenon caused by relative motion of ions close to a charged surface when a fluid moves past it. By measuring the streaming potential, information related to the surface properties of the rock, like charge and wettability can be gained. To get precise measurements of the streaming potential, a good experimental setup is required. The main purpose of this thesis was to set up the experiment, get reproducible results, and investigate if there was a systematic variation in the streaming potential by varying the brine composition. It turned out that it was important to reduce the effect of the static noise to get reproducible results. In that respect we used a method of flowing in both directions, and varied the flooding rate in a systematic way. The measurement methods implemented were paired stabilised (applying a constant rate and wait for a stable voltage and pressure) and pressure ramping with ranges between 240 seconds and 30 seconds (linearly increase the pressure and measure the streaming potential continuously). In this work we identified a clear response on the streaming potential and the salinity of the brine. Higher salinities are trickier to measure as the coupling coefficient is smaller. The results proved to be successful for salinities of NaCl up to 2 M and CaCl2 up to 0.2 M. At low salinity the measurements were reproducible, and with a variation of 2 % for the individual measurements. For medium salinities, the coupling coefficient was around 20 % higher in magnitude for rapid pressure ramping techniques (30 sec) than for slower ramping techniques (120-240 sec). For the high salinity brines, it was essential to implement rapid pressure ramping to avoid influence of static voltage.submittedVersio

Information Infastructure as Organization: A Critical Realist View

The notion of information infrastructures, introduced in the 1990s and refined during the past ten years, has proven quite fruitful to the IS field. It changed the perspective from organizations to networks and from systems to infrastructures, allowing for a global and emergent perspective on information systems. However, something is missing in this theory. What is an information infrastructure, ontologically? Is it a technical structure, an organizational form, an analytical perspective or a semantic network? This paper reviews the socio-technical origins of information infrastructures. Two propositions are described and discussed. First, that it is fruitful to regard information infrastructure as an ICT-based organizational form. Second, a critical realist view allows us to conceptualise the object of study in a simpler and more intuitive way. A case study of an airline company and a reinterpretation of Star and Ruhleder’s classic paper were used to illustrate the claims

IOS project motivation as a determinant of project activities and business capabilities

This paper investigates how innovation of ICT based services takes place within existing infrastructures, including the whole network of technology, vendors and customers. Our research question is, how can an information infrastructure provide generative mechanisms for innovation of ICT based services? Building on a critical realist approach, our empirical evidence was a case study within an international airline, aiming to diversify its services. From our analysis we propose that there are two self-reinforcement mechanisms in information infrastructures. First, we identified the innovation reinforcement mechanism, resulting in new services. Second, there is the service reinforcement mechanism, resulting in more users and profits. The practical implication of our framework is to show that although ICT-based innovation cannot be planned and managed in detail, the innovation mechanism may help organisations to facilitate the innovation process in a structured way

Autentisk Eksistens

I denne teksten presenterer jeg forskningen min på Autentisk Eksistens. Jeg argumenter for at autentisk væren ikke innebærer former for selv-aktualisering sett i moderne selv-hjelp litteratur. Istedenfor viser jeg hvordan autentisk væren innebærer en dekonstruksjon av en inautentisk form for selvhet. Denne teksten tar for seg hva autentisk eksistens er, hvordan det kan bli oppdaget, hva det motsier og forholdet til selvhet. Rollen til det jeg kaller problematiske tanker og deres forhold til inautentisitet og problemene i samtiden er også temaer som blir utforsket. Jeg diskuterer for hvordan man, ved å fjerne inautentiske mentale konstruksjonen slik som følelsesladdede personlige negative ‘narrativer’, problematiske tanker og ruminerende tankemøsntre bundet til et slags ‘jeg-konstrukt’ leder til en gjennoppdagelse av det som har blitt kalt en pre-reflektiv eksistensiell modus, som oppleves som autentisk. Teksten går gjennom hvordan oppbyggende deler av dette narrativt-genererte ‘jeg-konstruktet’ kan bli utforsket gjennom det fenomenologiske perspektivet, og hvordan en gjentatt bruk av denne prosessen via det som kalles ‘eksistensielle undersøkelser’ fjerner problematiske tanker i deres form av nevrotisk intern ‘selvprat’. Det blir argumentert at en gjenntakelse av eksistensiell selv-undersøkelse kan brukes som en måte til å overkomme inautentiske måter å være på til autentiske måter å være på. Avslutningsvis vil teksten utforske paralleller til denne tesen i form av nylig forskning av hjernens struktur og aktivitetsmoduser og hvordan dette relaterer til tesen om autentisk eksistens.Filosofi mastergradsoppgaveMAHF-FILOFILO35

Learning what democracy means in practice: A study on how textbooks can help promote competencies in upper secondary school

Dagens skoler må forberede elevene til å leve og jobbe i en raskt endrende verden. Fagfornyelsen kan bli sett på som et svar til dette, ved å introdusere nye temaer og fokusområder i overordnet del. Med denne oppgaven utforsker jeg i hvilken grad og på hvilke måter tekster, oppgaver og bilder i lærebøker i engelskfaget kan hjelpe med å promotere kompetanser i det tverrfaglige temaet ‘Demokrati og Medborgerskap’ og kjerneverdien ‘Demokrati og Medvirkning’ i videregående skole. Jeg gjennomførte en lærebok analyse av én lærebok, og så på innhold for å finne forskjellige trekk som kan hjelpe med å promotere relevante kompetanser. For å støtte under mine funn i læreboken som hadde en tilkobling til det tverrfaglige temaet og kjerneverdien, så ble interkulturell kompetanse og kritisk literacy introdusert for å fremheve viktigheten dette har for elever når de lærer om demokrati. Resultatene viste at det er vanskelig for forskningen som er gjort i denne oppgaven å svare på i hvilken grad, men lærerrollen er viktig når det kommer til dette punktet. Læreboken hadde mange forskjellige sider ved seg som kan hjelpe til å promotere kompetansene, og det har vært et fokus på noen av disse funnene for å vise i større grad hvordan lærebøker kan hjelpe til å promotere de.Schools today face the challenge of preparing pupils to live and work in a rapidly changing world. The LK20 can be seen as a response to this by introducing new topics and foci in the core curriculum. With this thesis, I investigate to what extent and in what ways texts, tasks, and illustrations in textbooks in the English subject can help promote competencies in the interdisciplinary topic ‘Democracy and Citizenship’ and core value ‘Democracy and Participation’ in upper secondary school. I conducted a textbook analysis of one textbook and looked at its content to find different features which can help promote relevant competencies. To further support the findings in the textbook, connected to the interdisciplinary topic and core value, intercultural competence and critical literacy were introduced to highlight the importance they have for pupils when learning about democracy. The results found that it is difficult for the research done in this thesis to answer ‘to what extent’ but the teacher role is important when it comes to the use of it. The textbook had lots of different features that can help promote the competencies, and there has been a focus on some of them to raise awareness of in what ways textbooks can help promote them

Design of Readout Electronics for the DEEP Particle Detector

Along with electromagnetic radiation, the Sun also emits a constant stream of charged particles in the form of solar wind. When these particles enter Earth’s atmosphere through a process known as particle precipitation, they can through a series of chemical reactions produce N Ox and HOx gases. These gases are greenhouse gases and deplete the ozone in the mesosphere and upper stratosphere. It is important to quantify the rate of production of these gases to model the potential climate impact. Existing particle detectors in space are suboptimal because they cannot determine the energy flux and pitch angle distribution of precipitating particles. The primary scientific objective of the DEEP project is to design a particle detector instrument that is specifically designed for particle precipitation measurements. This thesis investigates different data acquisition schemes for handling the signal from a pixel detector. The chosen approach is measuring the width of a shaped pulse to quantify the energy of the particle. Known as Time-over-Threshold, a detector circuit board is designed featuring high-speed comparators as threshold discriminators and the NG-MEDIUM FPGA from NanoXplore to implement the data acquisition. Digitizing the comparator pulse width is done with a Time-to-Digital converter (TDC) implemented in the FPGA fabric. Since the difference in pulse width is small for different energies, a high conversion resolution is required. Two high-resolution TDCs are designed and compared, both of which feature a digital counter and a method of interpolating the counter clock period. The first interpolation method applies the use of a multitapped delay line implemented with hard carry chain resources, and the second method oversamples the input with several equally off-phase sampling clocks. A resolution of 302 ps and a differential non-linearity of 3.26 was achieved with the delay line TDC clocked at 100 MHz. An automatic statistical calibration scheme is included to determine the actual delays of the delay line, utilizing a second asynchronous clock to generate uniformly distributed hits. The asynchronous oversampler resolution is clock frequency dependent and provides a 4-fold improvement to the clock period. The differential nonlinearity approaches zero with close matching of the off-phase clocks and operating frequency. A complete firmware design for the data acquisition and rocket telemetry of the detector is proposed and demonstrated. A simulation of the firmware utilizing each TDC topology is conducted and the delay line TDC is demonstrated to be the most accurate at all operating frequencies and thus the recommended TDC for the DEEP data acquisition.Masteroppgave i fysikkPHYS399MAMN-PHY

Wideband Self-Interference Cancellation Using Multi-Tap Filter in Radar Front End

The largest hurdle in full duplex wireless systems is the self-interference introduced by the transmitted signal into the received signal. In multi antenna systems this interference is caused by the direct coupling between the transmitting and receiving antennas. In systems where the transmitter and receiver uses the same antenna the interference is caused by inadequate isolation between the transmitter and receiver front-ends. In most systems the transmitted power is orders of magnitude higher than the received signal power. This causes the interference to saturate the receiver and can damage the receiver. One way of reducing this interference is to include a filter in the microwave front-end. This filter uses the transmitted signal to generate an inverse of the interference and adds it to the receiver signal path. In this thesis a multi-tap self-interference cancellation filter is designed, optimized and fabricated. The filter parameters are optimized using the basin-hopping algorithm combined with the Nelder-Mead downhill simplex algorithm. The filter is a multi-tap filter, where each tap contains phase shift, attenuation and delay elements. The filter is experimentally verified to reduce the self interference by 10.45 dB over a frequency band from 1GHz to 3GHz

Solar Calendar, And Other Ways of Marking Time

At the end of his life, Pierre Hadot was a professor at the Collège de France — a “professor’s professor” — and he helped Michel Foucault, most famously, conceptualize ethics. Hadot devoted his career to recovering the ancient conception of philosophy, according to which the discourses of universities are but a fragment of what philosophy is. His engagement with this theme helped Bendik-Keymer understand and develop a personal counter-culture to his academic work, a kind of original academics truer to the idea of the philosophical school Plato first developed in his Ἀκαδήµεια. But while Plato’s school developed a useful form of life, it had an ambivalent relation to democracy and to everyday people. Whereas Plato was in some ways one of the first egalitarians by merit (especially concerning women), he was also deeply classist in his categorization of intellectual potentials. He effectively thought some people were stupid by nature, having no philosophical worth. Hence the Ἀκαδήµεια existed outside the city, in practice exclusive and somewhat sequestered. To some extent, Plato’s vision of philosophy — at least as explained by Hadot — had the practical point of philosophy right, but this point still needed to be rendered thoroughly democratic in the polyphony and multiple intelligences of people. Doing so coheres with what Foucault was after in his application of Hadot. It is also what Bendik-Keymer is after — to extract what is good from original academics and make it democratic, as opposed to dumbing people down