Lifetime Based Health Indicator for Bearings using Convolitional Neural Networks

Master's thesis Renewable Energy ENE500 - University of Agder 2019Out of all the components in rotating electrical machinery, bearings have the highest failure rate. Bearingdegradation is a seemingly random process which is hard to both model and predict. Countless of con-dition based methods and algorithms have been proposed in order to accurately diagnose incipient faultsand estimate the remaining useful lifetime of bearings. These methods are often complex and hard to im-plement. In this thesis, a data-driven method of estimating a linear lifetime based health indicator (HI)using convolutional neural networks (CNNs) is proposed. The idea behind the method is to train a CNNmodel to recognize the shapes and distributions of vibration data in order to predict a HI with minimalpre-processing. Two models are presented: A CNN that takes time-series vibration data as input and aCNN that takes vibration frequency spectrum data as input. Finally, HIs are predicted on unique datasetsand their respective remaining useful lifetimes (RULs) are estimated as part of the model validation process.The results show that the models are able to recognize relevant fault features to a certain degree. However, accurate predictions have proven difficult in many cases

Simulating Private Information Retrieval on Amazon Web Services

As our modern lives have gradually moved more and more online, companies and state actors have taken it upon themselves to gather and analyze our behavior online, and as these actors have gradually shown just how much they know about a private user, or a group of users, a concern for privacy has grown accordingly. A virtual private network service could help anonymize a user, but the providers of services usually log what services they provide, which can provide identifying information. Research in privacy measures have thus become a larger topic in recent time. Private information retrieval allows a user to query a database without revealing to the server any information about the information queried, and if effective enough, could provide perfect privacy to everyone. In this thesis, we examine a state-of-the-art efficient private information retrieval scheme and study every step in the protocol in a simulation implemented on Amazon’s cloud computing services.Masteroppgave i informatikkINF399MAMN-PROGMAMN-IN

Between Iraq and a hard place : the change in republican foreign policy and the realism-neoconservatism debate

“How often have statesmen been motivated by the desire to improve the world, and ended up making it worse? And how often have they sought one goal, and ended up by achieving something they neither expected nor desired?” Hans J. Morgenthau (1993:6) With no peer competitor in sight, the United States is more powerful than any other nation state in modern history. The U.S. has substantial interests throughout the globe and its government seems to aim at remaining the sole superpower. The last five years have spurred a debate on the nature and purpose of this power and how best to make use of it. In the debates of the 2000 Presidential campaign, the then Governor Bush made a point of second-guessing former Vice President Al Gore’s agenda of active American involvement in a number of cases of conflict resolution abroad. To underline his point, Bush used the phrase “I would be very careful about using our troops as nation builders” in a derogative manner. The Republican foreign policy agenda was significantly more isolationist than that of the Democratic Clinton administration. Six years later, in George W. Bush’s second term as United States President, Republican foreign policy has taken on a large-scale war on terrorism and intervened in Afghanistan and Iraq, operations that would be seen as inconceivable a few years ago. Coercive democratization has since become the hallmark of the Bush Presidency. Which underlying mechanisms have caused this shift from the course of 2000 to new course of 2006? This thesis intends to examine how the theoretical bases of realism and idealism have guided the current Bush administration to choose the promotion of democracy over containment and deterrence. Most particularly, these shifts in policy lead the U.S. to attack Iraq, and to this date, express no intention of leaving in the near future

The implementation of a generalised robust adaptive controller

An adaptive controller is developed, comprising a robust parameter estimator and an explicit pole assignment controller design. The controller is reformulated to have a standard PID structure. A practical implementation is facilitated on a digital microcomputer, connected to a physical process. Test results are presented for this real process subject to variable dead-time and an external disturbance. Simulation results are also presented, for a nominally non minimum-phase process subject to variable dead-time and large open-loop gain changes. Robust performance is demonstrated under all of these circumstances. Recommendations are given for the choices and considerations required in a robust practical implementation. Much research has been done in the field of adaptive control over the past few decades. However, a let needs to be learned about the robustness of adaptive control algorithms. This research investigates the implementation of a practical adaptive control algorithm, with numerous features incorporated to improve the robust performance of such a controller. Parameter estimation is performed using Recursive Least Squares (RLS), with various signal conditioning filters to reduce estimator sensitivity to noise and modelling errors. The control design is based on closed-loop pole assignment, with adaptive feed forward compensation included. Further, provision is made in both the estimation model and the feedback control structure to eliminate deterministic immeasurable disturbances, and to track deterministic set point variations. This is based on the Internal Model Principle. Measured random disturbance signals are included in the estimation model, for which "transfer function" polynomial coefficients are estimated and then used in the feed forward control d e sign. A new shift- operator, namely the 6-operator, is used in all controller and estimator formulations. This has been shown to have better numerical properties and to correspond more closely to continuous-time control, than the traditional q operator of z-domain discrete control. A practical implementation on a digital computer is investigated, applied to a real plant typical of an industrial application. Simulation results are also obtained for plant with non minimum-phase zeros and variable dead-time

Star Wars Episod II: Om den säkerhetspolitiska utvecklingen i rymden efter kalla kriget

In this thesis I try to find out how multipolarity in space effects global security. My research question is as follows: What effects has the increasing amount of actors in space had on global security after the end of the cold war? Theories which I use to examine the effects are Kenneth Waltz perspective on the balance of power and Robert Jervis hypothesis on misperception. My hypothesis is that the multipolarity leads to militarization which despite the literature on the area does not have to lead to a decrease in global security. In my thesis I conclude that the multipolarity has led to increased problems with the institutionalization of space, that the multipolarity enhances the militarization of space and that it has limited effects on reducing misperceptions even though the technological development in space has increased the possibility for information retrieval. Due to this inference I conclude that the increased amount of actors in space has reduced global security since the end of the cold war

Landsskytterstevnets suksesskriterier og suksessfaktorer

Masteroppgave i økonomi og administrasjon - Universitetet i Agder 2012Utgangspunktet for denne oppgaven er å se på hvordan Landsskytterstevnet planlegges og gjennomføres. Oppgaven har som mål å finne ut hva som bidar til at arrangementet blir en suksess og derfor kunne si noe om hva arrangører av Landsskytterstevnet i fremtiden bør fokusere på. Oppgavens tredje del definerer suksesskriterier og suksessfaktorer og sammenhengen mellom disse. Teoridelen munner ut i figur 7 i del 3.4 Sammenheng mellom suksessfaktorer og suksesskriterier og forsøker å beskrive forholdet mellom disse. Undersøkelsen har en kvantitativ del og en supplerende kvalitativ del. I den kvantitative delen er det gjennomført en faktoranalyse av både suksesskriteriene og suksessfaktorene. En regresjonsanalyse og korrelasjonsanalyse er videre gjennomført for suksessfaktorene. Faktoranalysen grupperer variabler sammen og er utgangspunktet for faktorene som videre analyseres. Landsskytterstevnet vurderes å være en stor suksess av både arrangører, skyttere, foresatte til skyttere og publikum. Arrangørene vurderer stevnene i større grad enn brukerne å være en suksess. Suksessfaktorene F.1 Prosjektets_målsetting, F.7 Frivillige og F.14 Læring_fra_eget_LS fremgår av den kvantitative analysen som de viktigste for å oppnå suksess. Den kvalitative analysen viser at flere, og andre, faktorer er viktige for oppnåelsen av suksess. Analysen viser at hovedfokuset bør legges på faktorene F.2 Støtte_fra_toppledelsen, F.8 Organisering_av_teamet, F.10 Kommunikasjon, F.12 Problemløsing og F.13 Læring_fra_andre_LS

Analisis Pengetahuan Mahasiswa Tentang Karies Gigi terhadap Indeks Dmf-t pada Mahasiswa STIKES YARSI Jurusan Keperawatan Bukittinggi

Kesehatan gigi dan mulut telah mengalami peningkatan pada abad terakir tetapi tingginya angka karies menjadi masalah yang sangat serius. Penelitian ini bertujuan untuk melihat gambaran pengetahuan mahasiswa tentang karies gigi terhadap indeks DMF-T pada mahasiswa STIKES Yarsi Jurusan Keperawatan.m Penelitian ini menggunakan jenis penelitian deskriptif. Populasi penelitian adalah seluruh mahasiswa STIKES Yarsi Jurusan Keperawatan dengan sampel sebanyak 47 orang diambil dengan teknik judgement sampling.mHasil penilitian menunjukkan bahwa 37 orang (78 %) memiliki pengetahuan cukup dan 10 orang (22 %) memiliki pengetahuan baik tentang karies gigi, sedangkan 24 orang (51 %) memiliki indeks DMF-T dengan kriteria jelek dan 23 orang (49 %) memiliki indeks DMF-T dengan kriteria baik. Kesimpulan dalam penelitian ini yaitu pengetahuan mahasiswa tentang karies gigi dengann kriteria cukup mempunyai indeks DMF-T jelek. Disarankan kepada responden untuk lebih meningkatkan pengetahuan tentang cara menjaga kesehatan gigi dan mulu