Profitability Analysis of Service Contracts of Devices

The objective of this study has been to make a profitability analysis of service contracts for a company in Finland. The purpose has been to see how profitable the contracts are and if there possibly were some things to change or develop in the contracts. Allocation rules of cost accounting, service costs both profitability and management of services have been considered in the theory part. All the service contracts that have been valid at least three last accounting periods have been included in the study. All direct costs relating to the contracts have been collected and indirect costs have been assigned to the contracts. Profitability of the contracts has been calculated over three years. Results have been analyzed according to the key figures the company is controlling. Some suggestions for developments have been given at the end of the study. The study has shown differences between the contracts. Part of them has turned out to be like the profitability aims of the company and part less profitable. The study has shown that many factors have an effect on the profitability of the service contracts.

Context exchange between devices in mobile environment

Context awareness is emerging on mobile devices. Context awareness can be used to improve usability of a mobile device. Context awareness is particularly important on mobile devices due the limitations they have. At first in this work, a literature review on context awareness and mobile environment is made. For aiding context awareness there exist an implementation of a Context Framework for Symbian S60 devices. It provides a possibility for exchanging the contexts inside the device between the client applications of the local Context Framework. The main contribution of this thesis is to design and implement an enhancement to the S60 Context Framework for providing possibility to exchange context over device boundaries. Using the implemented Context Exchange System, the context exchange is neither depending on the type of the context nor the type of the client. In addition, the clients and the contexts can reside on any interconnected device. The usage of the system is independent of the programming language since in addition to using only Symbian C++ function interfaces it can also be utilized using XML scripts. The Meeting Sniffer application, which uses the Context Exchange System, was also developed in this work. Using this application, it is possible to recognize a meeting situation and suggest device profile change to a user.

Concentrated Winding Multiphase Permanent Magnet Machine Design and Electromagnetic Properties – Case Axial Flux Machine

Concentrated winding permanent magnet machines and their electromagnetic properties are studied in this doctoral thesis. The thesis includes a number of main tasks related to the application of permanent magnets in concentrated winding open slot machines. Suitable analytical methods are required for the first design calculations of a new machine. Concentrated winding machines differ from conventional integral slot winding machines in such a way that adapted analytical calculation methods are needed. A simple analytical model for calculating the concentrated winding axial flux machines is provided. The next three main design tasks are discussed in more detail in the thesis. The magnetic length of the rotor surface magnet machines is studied, and it is shown that the traditional methods have to be modified also in this respect. An important topic in this study has been to evaluate and minimize the rotor permanent magnet Joule losses by using segmented magnets in the calculations and experiments. Determination of the magnetizing and leakage inductances for a concentrated winding machine and the torque production capability of concentrated winding machines with different pole pair numbers are studied, and the results are compared with the corresponding properties of integral slot winding machines. The thesis introduces a new practical permanent magnet motor type for industrial use. The special features of the machine are based on the option of using concentrated winding open slot constructions of permanent magnet synchronous machines in the normal speed ranges of industrial motors, for instance up to 3000 min-1, without excessive rotor losses. By applying the analytical equations and methods introduced in the thesis, a 37 kW 2400 min-1 12-slot 10-pole axial flux machine with rotor-surfacemounted magnets is designed. The performance of the designed motor is determined by experimental measurements and finite element calculations.

Microwave Processes in Ferrite-ferroelectric Layered Structure

This work is devoted to investigation of wave processes in new hybrid ferrite/ferroelectric structures. Spin wave devices based on ferrite films have disadvanteges. And their applications are limited. Investigated structures allow to overcome disadvantages. This investigation helps to create new class of devices. Electromagnetic analysis of hybrid spin-electromagnetic waves in ferrite/ferroelectric structures were done. As a result dispersion relation was found. Numerical solution of this dispersion relation gave us follow results. These structures can be effectively tuned by external electric and magnetic field. Methods to increase tuning range were suggested. It was found that such structures have one basic disadvantage which is connected with presence of thick ferroelectric layer. To solve this problem is to use thin ferroelectric films. But this decreases tuning range. It was confirmed by experiment that this structures can be effectively tuned by electric and magnetic fields. Resonance characteristics of ferrite/ferroelectric resonator were succesfully tuned by magnetic and electric field.

Combined electromagnetic and thermal design platform for totally enclosed induction machines

The aim of the thesis is to design a suitable thermal model that can be used as a tool for constructing the TEFC squirrel cage induction machine in addition to the electromagnetic model. A lumped-parameter thermal model is developed. The related problems and aspects of implementation are discussed in details. Losses are calculated analytically and the loss values are used in the thermal model. The sensitivity analysis is introduced to determine the most critical parameters of the model.

Certificate Handling Middleware for Mobile Devices

The purpose of this thesis was to study how certificates could be used to improve security of mobile devices. In the theoretical part the usage of certificates to improve security is explained. In the practical part a concept of certificate handling middleware is introduced and implemented. This is to demonstrate what kind of functionality is needed to provide an improvement over the current situation in security with mobile devices. The certificate handling middleware is a concept that would work better if implemented directly into mobile device's core functionality. Many of the mobile devices have a certificate store to some degree and often it is not used to store other people's certificates. A certificate store combined with address book and added with possibility to add attributes to the people such as group memberships would be sufficient to satisfy the needs of many emerging sharing and social applications.

Studies on the Multifaceted Interaction of Atoms and an Electromagnetic Field

In this Thesis the interaction of an electromagnetic field and matter is studied from various aspects in the general framework of cold atoms. Our subjects cover a wide spectrum of phenomena ranging from semiclassical few-level models to fully quantum mechanical interaction with structured reservoirs leading to non-Markovian open quantum system dynamics. Within closed quantum systems, we propose a selective method to manipulate the motional state of atoms in a time-dependent double-well potential and interpret the method in terms of adiabatic processes. Also, we derive a simple wave-packet model, based on distributions of generalized eigenstates, explaining the finite visibility of interference in overlapping continuous-wave atom lasers. In the context of open quantum systems, we develop an unraveling of non-Markovian dynamics in terms of piecewise deterministic quantum jump processes confined in the Hilbert space of the reduced system - the non-Markovian quantum jump method. As examples, we apply it for simple 2- and 3-level systems interacting with a structured reservoir. Also, in the context of ion-cavity QED we study the entanglement generation based on collective Dicke modes in experimentally realistic conditions including photonic losses and an atomic spontaneous decay.

Real-time Musical Pair Improvisation on Mobile Devices

This thesis discusses the design and implementation of a real-time musical pair improvisation scenario for mobile devices. In the scenario transferring musical information over a network connection was required. The suitability of available wireless communication technologies was evaluated and communication was analyzed and designed on multiple layers of TCP/IP protocol stack. Also an application layer protocol was designed and implemented for the scenario. The implementation was integrated into a mobile musical software for children using available software components and libraries although the used platform lead to hardware and software constraints. Software limitations were taken into account in design. The results show that real-time musical improvisation can be implemented with wireless communication and mobile technology. The results also show that link layer had the most significant effect on real-time communication in the scenario.

The Usage of Microsoft Push Notification Service on Mobile Devices

Along with the increasing in demand of mobile computing, Push Notification (PN) is widely used in mobile phones and other devices. PN allows the developer to send messages to the end users even when the client application is not running at the moment. This solves the problem produced by non-supported multi-tasking feature as well as saving battery life. Microsoft Push Notification Service (MPNS) is one solution to use PNs in Windows Phones. The thesis gives the developers an idea of how to use PNs by introducing MPNS, comparing MPNS with other Push Notification Services, usage of different PN types analysis, and PN simulation system implementation.

Construction Plan Image Service for Mobile Devices

The forthcoming media revolution of exchanging paper documents to digital media in construction engineering requires new tools to be developed. The basis of this bachelor’s thesis was to explore the preliminary possibilities of exporting imagery from a Building Information Modelling –software to a mobile phone on a construction yard. This was done by producing a Web Service which uses the design software’s Application Programming Interface to interact with a structures model in order to produce the requested imagery. While mobile phones were found lacking as client devices, because of limited processing power and small displays, the implementation showed that the Tekla Structures API can be used to automatically produce various types of imagery. Web Services can be used to transfer this data to the client. Before further development the needs of the contractor, benefits for the building master and inspector and the full potential of the BIM-software need to be mapped out with surveys.

Taksamittarin EMC-testaus

Työssä esitellään ajoneuvokäytössä elektronisiin laitteisiin mahdollisesti vaikuttavat sähkömagneettiset häiriöt, kytkeytyneiden häiriöiden siirtotiet sekä kytkeytyneiden häiriöiden muodot. Työssä käydään läpi lyhyesti tapoja joilla häiriön syntyä voidaan vähentää. Lisäksi työssä käydään läpi lyhyesti tapoja joilla häiriön vaikutusta voidaan pyrkiä vähentämään. Työssä esitellään laite, jonka mahdollisuuksia toimia taksin taksamittarina tutkitaan. Taksin taksamittarin tulee täyttää Euroopan Unionin alueella myynnissä ollessaan täyttää Euroopan Unionin asettama direktiivi ajoneuvoelektroniikalle, lisäksi laitteen tulee täyttää Euroopan Unionin mittalaitedirektiivin asettamat vaatimukset. Esitellyn laiteen häiriönsietoa testataan sähkökenttää vastaan Euroopan Unionin asettaman direktiivin mukaisesti.

Reducing contact resistance in graphene devices

In this thesis, the contact resistance of graphene devices was investigated because high contact resistance is detrimental to the performance of graphene field-effect transistors (GFET). Method for increasing so-called edge-contact area was applied in device fabrication process, as few nanometers thick Ni layer was used as a catalytic etchant during the annealing process. Finally, Ni was also used as a metal for contact. GFETs were fabricated using electron beam lithography using graphene fabricated by chemical vapor deposition (CVD). Critical part of the fabrication process was to preserve the high quality of the graphene channel while etching the graphene at contact areas with Ni during the annealing. This was achieved by optimizing the combination of temperature and gas flows. The structural properties of graphene were studied using scanning electron microscopy, scanning confocal μ-Raman spectroscopy and optical microscopy. Evaluation of electric transport properties including contact resistance was carried out by transmission line method and four-probe method. The lowest contact resistance found was about at 350 Ωμm. In addition, different methods to transfer CVD graphene synthesized on copper were studied. Typical method using PMMA as a supporting layer leaves some residues after its removal, thus effecting on the performance of a graphene devices. In a metal assisted transfer method, metal is used as an interfacial layer between PMMA and graphene. This allows more effective removal of PMMA. However, Raman spectra of graphene transferred by metal assisted method showed somewhat lower quality than the PMMA assisted method

Vibrations in Rotating Machinery Arising from Minor Imperfections in Component Geometries

Vibrations in machines can cause noise, decrease the performance, or even damage the machine. Vibrations appear if there is a source of vibration that excites the system. In the worst case scenario, the excitation frequency coincides with the natural frequency of the machine causing resonance. Rotating machines are a machine type, where the excitation arises from the machine itself. The excitation originates from the mass imbalance in the rotating shaft, which always exists in machines that are manufactured using conventional methods. The excitation has a frequency that is dependent on the rotational speed of the machine. The rotating machines in industrial use are usually designed to rotate at a constant rotational speed, the case where the resonances can be easily avoided. However, the machines that have a varying operational speed are more problematic due to a wider range of frequencies that have to be avoided. Vibrations, which frequencies equal to rotational speed frequency of the machine are widely studied and considered in the typical machine design process. This study concentrates on vibrations, which arise from the excitations having frequencies that are multiples of the rotational speed frequency. These vibrations take place when there are two or more excitation components in a revolution of a rotating shaft. The dissertation introduces four studies where three kinds of machines are experiencing vibrations caused by different excitations. The first studied case is a directly driven permanent magnet generator used in a wind power plant. The electromagnetic properties of the generator cause harmonic excitations in the system. The dynamic responses of the generator are studied using the multibody dynamics formulation. In another study, the finite element method is used to study the vibrations of a magnetic gear due to excitations, which frequencies equal to the rotational speed frequency. The objective is to study the effects of manufacturing and assembling inaccuracies. Particularly, the eccentricity of the rotating part with respect to non-rotating part is studied since the eccentric operation causes a force component in the direction of the shortest air gap. The third machine type is a tube roll of a paper machine, which is studied while the tube roll is supported using two different structures. These cases are studied using different formulations. In the first case, the tube roll is supported by spherical roller bearings, which have some wavinesses on the rolling surfaces. Wavinesses cause excitations to the tube roll, which starts to resonate at the frequency that is a half of the first natural frequency. The frequency is in the range where the machine normally operates. The tube roll is modeled using the finite element method and the bearings are modeled as nonlinear forces between the tube roll and the pedestals. In the second case studied, the tube roll is supported by freely rotating discs, which wavinesses are also measured. The above described phenomenon is captured as well in this case, but the simulation methodology is based on the flexible multibody dynamics formulation. The simulation models that are used in both of the last two cases studied are verified by measuring the actual devices and comparing the simulated and measured results. The results show good agreement.

Spectroscopic Studies of III-V Semiconductor Materials for Improved Devices

Defects in semiconductor crystals and at their interfaces usually impair the properties and the performance of devices. These defects include, for example, vacancies (i.e., missing crystal atoms), interstitials (i.e., extra atoms between the host crystal sites), and impurities such as oxygen atoms. The defects can decrease (i) the rate of the radiative electron transition from the conduction band to the valence band, (ii) the amount of charge carriers, and (iii) the mobility of the electrons in the conduction band. It is a common situation that the presence of crystal defects can be readily concluded as a decrease in the luminescence intensity or in the current flow for example. However, the identification of the harmful defects is not straightforward at all because it is challenging to characterize local defects with atomic resolution and identification. Such atomic-scale knowledge is however essential to find methods for reducing the amount of defects in energy-efficient semiconductor devices. The defects formed in thin interface layers of semiconductors are particularly difficult to characterize due to their buried and amorphous structures. Characterization methods which are sensitive to defects often require well-defined samples with long range order. Photoelectron spectroscopy (PES) combined with photoluminescence (PL) or electrical measurements is a potential approach to elucidate the structure and defects of the interface. It is essential to combine the PES with complementary measurements of similar samples to relate the PES changes to changes in the interface defect density. Understanding of the nature of defects related to III-V materials is relevant to developing for example field-effect transistors which include a III-V channel, but research is still far from complete. In this thesis, PES measurements are utilized in studies of various III-V compound semiconductor materials. PES is combined with photoluminescence measurements to study the SiO2/GaAs, SiNx/GaAs and BaO/GaAs interfaces. Also the formation of novel materials InN and photoluminescent GaAs nanoparticles are studied. Finally, the formation of Ga interstitial defects in GaAsN is elucidated by combining calculational results with PES measurements.