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  • Dimitry El Baghdady, Johan
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Equilibrium Strategies for Time-Inconsistent Stochastic Optimal Control of Asset Allocation2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    We have examinined the problem of constructing efficient strategies for continuous-time dynamic asset allocation. In order to obtain efficient investment strategies; a stochastic optimal control approach was applied to find optimal transaction control. Two mathematical problems are formulized and studied: Model I; a dynamic programming approach that maximizes an isoelastic functional with respect to given underlying portfolio dynamics and Model II; a more sophisticated approach where a time-inconsistent state dependent mean-variance functional is considered. In contrast to the optimal controls for Model I, which are obtained by solving the Hamilton-Jacobi-Bellman (HJB) partial differential equation; the efficient strategies for Model II are constructed by attaining subgame perfect Nash equilibrium controls that satisfy the extended HJB equation, introduced by Björk et al. in [1]. Furthermore; comprehensive execution algorithms where designed with help from the generated results and several simulations are performed. The results reveal that optimality is obtained for Model I by holding a fix portfolio balance throughout the whole investment period and Model II suggests a continuous liquidation of the risky holdings as time evolves. A clear advantage of using Model II is concluded as it is far more efficient and actually takes time-inconsistency into consideration.

  • Hallqvist, Kristoffer
    KTH, School of Computer Science and Communication (CSC).
    Dynamic label placement for moving objects2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In command and control systems, for example air traffic control, operators must view many moving objects simultaneously. Graphical labels that identify objects move along with them, and for readability it is important that such labels do not overlap or hop around erratically as objects come close to each other. Instead, the labels should smoothly revolve around their objects. The goal of this thesis is to explore label placement strategies for moving objects that avoid overlap and hopping effects. In this thesis, we consider a simplified problem, in which time is coarsely discretized and each label is of a fixed size and can only be displayed in a limited number of distinct positions relative to its corresponding object. An optimal and a reactive heuristic algorithm are developed and applied to a number of test cases, which are then analysed for different statistical measures. In a scene with 25 objects traveling across a common area, the reactive algorithm is on average able to keep approximately half of the labels visible the whole time, whereas the optimal algorithm could only be applied to test cases with at most four objects. A prediction mechanism is implemented that on average decreases the number of times labels alternate between being hidden and visible. Future work could investigate how users perceive the usability of a system implementing the reactive algorithm.

  • Le, Yvonne
    KTH, School of Computer Science and Communication (CSC).
    Choosing the most reasonable split of a compound word using Wikipedia2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this master thesis is to make use of the category taxonomy of Wikipedia to determine the most reasonable split from the suggestions generated by an independent compound word splitter.

    The articles a word was found in can be seen as a group of contexts the word can occur in and also different representations of the word, i.e. an article is a representation of the word. Instead of only analysing the data of each single article, the intention is to find more data for each representation/context to perform an analysis on. The idea is to expand each article representing one context by including related articles in the same category.

    Two perceptions of a ”reasonable split” was studied. The first case was a split consisting of only two parts and the second case of unlimited parts.

    This approach is well-suited for choosing the correct split out of a several suggestions but unsuitable for identifying compound words. It would more often than not decide to not split a compound word. It is very dependant on the compound words appearing in Wikipedia.

  • Public defence: 2017-03-20 10:00 B24, Stockholm
    Teng, Penghua
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    CFD MODELLING OF TWO-PHASE FLOWS AT SPILLWAY AERATORS2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Due to the high-speed flow in a chute spillway, cavitation damages often occur. This undesired phenomenon threatens the safety of the structure. For the purpose of eliminating the damages, an aerator is often installed in the spillway. To understand its characteristics, physical model tests are a popular method. To complement the model tests, computation fluid dynamics (CFD) simulations are used to study aerator flows. To represent the two-phase flows, multiphase models should be employed. This thesis examines two of them, namely, the Volume-Of-Fluid model (VOF) and Two-Fluid model.

    Based on the background of the Bergeforsen dam, the aerator flow is modelled by means of the VOF model. The simulated spillway discharge capacity is in accordance with the experimental data. Compared with the results, empirical formulas fail to evaluate the air supply capacity of aerator as it is wider than the conventional width. A hypothetical vent modification is proposed. For the original and proposed layouts, the study illustrates the difference in the air-flow conditions. The results show that a larger vent area is, for a large-width aerator, preferable in the middle of the chute.

    To study the flip bucket-shaped aerators in the Gallejaur dam, physical model tests and prototype observations are conducted. The results lead to contradicting conclusions in terms of jet breakup and air entrainment. A CFD model is, as an option, employed to explain the reason of the discrepancy. The numerical results coincide with the prototype observations. The jet breakup and air entrainment are evaluated from air cavity profiles; the air-pressure drops are small in the cavity. The discrepancy is due to overestimation of the surface-tension effect in the physical model tests.

    Based on the experimental data of an aerator rig at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, the Two-Fluid model is used to predict air concentration distributions in the aerated flow. The model includes relevant forces governing the motion of bubbles and considers the effects of air bubble size. The numerical results are conformable to the experiments in the air cavity zone. Downstream of the cavity, the air concentration near the chute bottom is higher, which is presumably caused by the fact that the interfacial forces in the Two-Fluid model are underestimated.

  • Carlsson, Hannes
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Development of a Depth Controller for the SEAL Carrier2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The SEAL Carrier is a hybrid marine vessel capable of traveling both fast on the water surface and completely submerged.Due to the craft's hydrodynamical properties it is taxing on the pilots to keep the SEAL Carrier at a certain depth for longer periods of time, therefore it is desirable to have a depth controller. A model was developed to describe the forces from the actuators and the depth, pitch and speed controlled through a PI controller using a backstepping approach. The resulting controller was implemented and validated in Simulink and, as there exist a Simulink model of the craft, also tested and tuned. The Simulink implementation was turned into C++ code in order to be implemented on board the SEAL Carrier.The simulations provide promising results, though further tests should be performed to ensure the robustness of the controller, as the Simulink model has difficulties capturing all of the dynamics of the craft.

  • Public defence: 2017-03-17 10:00 D3, Stockholm
    Gil Gómez, Gaspar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. Volvo Cars.
    Towards efficient vehicle dynamics development: From subjective assessments to objective metrics, from physical to virtual testing2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Vehicle dynamics development is strongly based on subjective assessments (SA) of vehicle prototypes, which is expensive and time consuming. Consequently, in the age of computer- aided engineering (CAE), there is a drive towards reducing this dependency on physical test- ing. However, computers are known for their remarkable processing capacity, not for their feelings. Therefore, before SA can be computed, it is required to properly understand the cor- relation between SA and objective metrics (OM), which can be calculated by simulations, and to understand how this knowledge can enable a more efficient and effective development process.

    The approach to this research was firstly to identify key OM and SA in vehicle dynamics, based on the multicollinearity of OM and of SA, and on interviews with expert drivers. Sec- ondly, linear regressions and artificial neural network (ANN) were used to identify the ranges of preferred OM that lead to good SA-ratings. This result is the base for objective require- ments, a must in effective vehicle dynamics development and verification.

    The main result of this doctoral thesis is the development of a method capable of predicting SA from combinations of key OM. Firstly, this method generates a classification map of ve- hicles solely based on their OM, which allows for a qualitative prediction of the steering feel of a new vehicle based on its position, and that of its neighbours, in the map. This prediction is enhanced with descriptive word-clouds, which summarizes in a few words the comments of expert test drivers to each vehicle in the map. Then, a second superimposed ANN displays the evolution of SA-ratings in the map, and therefore, allows one to forecast the SA-rating for the new vehicle. Moreover, this method has been used to analyse the effect of the tolerances of OM requirements, as well as to verify the previously identified preferred range of OM.

    This thesis focused on OM-SA correlations in summer conditions, but it also aimed to in- crease the effectiveness of vehicle dynamics development in general. For winter conditions, where objective testing is not yet mature, this research initiates the definition and identifica- tion of robust objective manoeuvres and OM. Experimental data were used together with CAE optimisations and ANOVA-analysis to optimise the manoeuvres, which were verified in a second experiment. To improve the quality and efficiency of SA, Volvo’s Moving Base Driving Simulator (MBDS) was validated for vehicle dynamics SA-ratings. Furthermore, a tablet-app to aid vehicle dynamics SA was developed and validated.

    Combined this research encompasses a comprehensive method for a more effective and ob- jective development process for vehicle dynamics. This has been done by increasing the un- derstanding of OM, SA and their relations, which enables more effective SA (key SA, MBDS, SA-app), facilitates objective requirements and therefore CAE development, identi- fies key OM and their preferred ranges, and which allow to predict SA solely based on OM. 

  • Andersson, Dorothea
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Simulation of industrial control system field devices for cyber security2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Industrial Control Systems (ICS) are an integral part of modernsociety, not least when it comes to controlling and protecting criticalinfrastructure such as power grids and water supply. There is a need to testthese systems for vulnerabilities, but it is often difficult if not impossible to doso in operational real time systems since they have been shown to be sensitiveeven to disturbances caused by benign diagnostic tools. This thesis exploreshow ICS field devices can be simulated in order to fool potential antagonists,and how they can be used in virtualized ICS for cyber security research. 8different field devices were simulated using the honeypot daemon Honeyd,and a generally applicable simulation methodology was developed. It was alsoexplored how these simulations can be further developed in order to functionlike real field devices in virtualized environments.

  • Nithin Jose, Madassery
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Design and layout of power conversion chain for a wave energy converter2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wave energy has the potential to provide an energy resource in this challenging energyenvironment. Wave energy converters are devices used to extract this energy and convertit into electricity. Wave Carpet is an example of such a novel wave energy converters andin its final form, it consists of a submerged membrane which covers an arbitrarily largearea above the sea floor. Incident waves create a pressure difference between the upper andlower surfaces, which triggers an up-and-down movement. The power take-off attached tothe surfaces serve to restrict this movement and thereby extract hydraulic power which isconverted to electricity.The Wave Carpet, is a type of wave energy converter that is beingdeveloped at University of California Berkeley′s Theoretical and Applied Fluid DynamicsLaboratory (TAFLab).The thesis aims at modeling and designing the different power conversion chainof the entire wave energy converter device. The process of energy conversion that yieldsthe required electrical energy for connecting a wave energy converter to an electricalnetwork is termed as the power conversion chain. A detailed electro-mechanical modelof the wave energy converter system connected to power grid is developed in theMatlab/SIMULINK environment and its corresponding generator and hydraulic controlstructure is implemented. The simulation response of the wave energy converter alongwith the power conversion chain is investigated.

  • Public defence: 2017-03-24 10:00 M311, Stockholm
    Alhusin Alkhdur, Abdullah
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Toward a Sustainable Human-Robot Collaborative Production Environment2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This PhD study aimed to address the sustainability issues of the robotic systems from the environmental and social aspects. During the research, three approaches were developed: the first one an online programming-free model-driven system that utilises web-based distributed human-robot collaboration architecture to perform distant assembly operations. It uses a robot-mounted camera to capture the silhouettes of the components from different angles. Then the system analyses those silhouettes and constructs the corresponding 3D models.Using the 3D models together with the model of a robotic assembly cell, the system guides a distant human operator to assemble the real components in the actual robotic cell. To satisfy the safety aspect of the human-robot collaboration, a second approach has been developed for effective online collision avoidance in an augmented environment, where virtual three-dimensional (3D) models of robots and real images of human operators from depth cameras are used for monitoring and collision detection. A prototype system is developed and linked to industrial robot controllers for adaptive robot control, without the need of programming by the operators. The result of collision detection reveals four safety strategies: the system can alert an operator, stop a robot, move away the robot, or modify the robot’s trajectory away from an approaching operator. These strategies can be activated based on the operator’s location with respect to the robot. The case study of the research further discusses the possibility of implementing the developed method in realistic applications, for example, collaboration between robots and humans in an assembly line.To tackle the energy aspect of the sustainability for the human-robot production environment, a third approach has been developed which aims to minimise the robot energy consumption during assembly. Given a trajectory and based on the inverse kinematics and dynamics of a robot, a set of attainable configurations for the robot can be determined, perused by calculating the suitable forces and torques on the joints and links of the robot. The energy consumption is then calculated for each configuration and based on the assigned trajectory. The ones with the lowest energy consumption are selected.

  • Lang, Renfei
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Evaluation of Measurement on Small Arc Features using CMM2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to the fast development of the tooling solutions technology, the manufacturing accuracy of inserts from Sandvik Coromant AB, Gimo, Sweden have been tremendously improved and they are hence focusing on enhancing the measuring accuracy of small arc features on inserts, because the measuring accuracy and method of the current CMM in the factory may not satisfy the requirement of tiny features. This report aims to investigate the relation between the measurement uncertainty and the radius as well as angle of arcs, through experiments, in order to observe the achievable specification limits with different radii and angles.The research objects are four carbide-cemented gauges with different radius, which are divided into four groups. Every gauge is scanned circularly by a CMM and the point coordinates are recorded before the coordinates are further processed by an Excel macro to acquire the results with different angles. After each experiment is repeated ten times, all data are integrated and analyzed. The specification limits under different combinations of radii and angles are calculated and treatedas the ‘best case scenario’ for future researches. Additionally, the analys is also indicates that the measurement uncertainty is not strongly related with the arc radius, instead, it is obviously affected by the angle of the accessible arc. It is also revealed in the last chapter of this report that limitations still exist in this research and the future suggestion has also been proposed.

  • Malgerud, Johan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Skarp, Daniel
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Energy efficient control of a low voltage motor to extend battery life2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The interest for electromechanical locks is constantly increasing, with its many advantages over the purely mechanical varieties, such as intelligent access schedules, online access handling, and cheaper credentials. These applications are often battery powered making the need for energy conservation crucial when extending the battery lifetime.This master thesis will reduce the energy consumption of the ASSA ABLOY, Aperio E100 lock using more intelligent control of the motor, as well as by selecting more suitable hardware. The thesis starts out by evaluating different actuator types, and selecting the most suitable for the Aperio E100 application. An in depth study for this motor type then reveals new energy efficient control methods for this.A brushless DC motor is chosen to replace the current brushed DC motor in the application. A voltage trajectory method is then used to reduce the consumption, by simulating input steps using MATLAB. The total consumption of the brushed DC motor was reduced with 33%, and the brushless DC motor with 89%. These reductions in the motor consumption lead to a theoretical increase in the battery life of 8 and 17,6months respectively.

  • Public defence: 2017-03-10 13:00 Kollegiesalen, Stockholm
    Ehrnberger, Karin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Product and Service Design.
    TILLBLIVELSER: En trasslig berättelse om design som normkritisk praktik2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The increasing awareness of norm-critical perspectives (in society, academia and industry) brings with it the need to develop methods to ensure they can be implemented in practice. This thesis discusses how the role of design contributes to and maintains norms, and shows how design as a norm critical practice has great potential to bridge the gap between theory and practice in norm-critical work. This potential lies in using design as a peda-gogic tool that can concretize and make understandable what would otherwise be perceived as complex, unclear or remote. The thesis pays special attention to the role of artefacts in the creation of the stories of the world. The discursive design thing is introduced as a tool to visualize norms and to create discussion. The three-dimensional, physical thing exposes us to a more diverse experience of norms than when we just address them in words or pictures.The empirical work in this thesis stems from five research projects that differ from each other and were carried out under varied conditions. The projects have tackled a range of problems and power relationships. However, together they draw a complex picture of how norms arise, overlap and constantly change over time, place and space – and how design can be used to support or disrupt this process.By revisiting the projects, it becomes clear how the researcher’s position and actions (or non-actions) shape the norm development process. This results in an insight that meaning can not be construc-ted from an outside perspective, but is a constant ”becoming” that occurs in an entanglement of relationships arising between different bodies, both human and non-human. As a norm critical perspective implies paying attention to power relationships, it also assumes a power critical approach to the production of meaning extracted from the norm-critical work, and that we – as researchers and designers – take responsibility for our prevail by highlighting our own bodies and gaze.The thesis therefore proposes the concept of diffraction as an approach to the production of meaning in norm critical design practices. A diffractive approach enables an understanding of how the production of meaning occurs in various coincidences, but also how our own interventions shape the story. It opens up to the realization that parallel narratives are possible and thus becomes a tool to break away from the linear understanding framework and offer an exploration of alternative thought patterns. A diffractive approach to the production of meaning is thus also a tool to pro-mote increased creativity.

  • Norberg, Johan
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Demand Response In The Engineering Industry2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The power utilities in Sweden are planning to replace the major part of thenuclear power plants with renewable energy resource by the year 2030. Some ofthe renewable energy resources are intermittent, which may endanger the powersystem stability. A solution to this problem could be increased exibility in theend-users consumption, which is known as demand response. This is a usefultool that can be used to facilitate the large integration of renewable energyresource into the power grid. Therefore, several of the Swedish governmentauthorities have stated that the possibilities for demand response should befurther investigated.During this thesis, a case study is carried out at Volvo Group Truck OperationsPowertrain Productions in Koping, with the purpose of deriving theirtechnical possibilities for DR in the factory. Volvo in Koping mainly producesgearboxes to all trucks within the Volvo Group concern and belongs to the engineeringindustry sector. The engineering industry has previously not beeninvestigated for DR purposes in Sweden. The main goal of the thesis is to derivethe DR capacity of the factory and the associated time parameters. Onlydemand response by shifting the production in time is considered.One production group (Midiblock 2) in the factory is modelled using MixedInteger Linear Programming and the optimization problem is used to minimizethe electricity cost while fullling the production requirements. The optimizationproblem is done on daily basis and the result is binary operating pointsfor CNC-machines. The output from the Mixed Integer Linear Programmingproblem is sent to a discrete event model, which is used to validate the resultsand display the optimal energy consumption.The simulation results indicates that the modelled production group can performa load shift of 270 kWh/h during 4 hours by scheduling production. Duringthe reduction it should be possible to perform actions such as maintenance andchanging settings of machines. If the results are true for the entire factory, theresulting load reduction is 1.35 MWh/h during 4 hours. However, the nancialincentives to perform load reductions are low. Also, Volvo in Koping does nothave any routines to shut-o the CNC-machines and an extensive work is requiredto make a load reduction possible. Resulting in that DR at the factory isat the moment unrealistic. In addition to the possibilities for DR, the possibleeconomic savings by shutting o the CNC-machines when they are not producingunits are also approximated. Volvo in Koping can save a large amount ofenergy and yearly cut the cost by at least 5 000 000 SEK on these actions, whichis also the rst step towards enabling DR in the factory.

  • Dickeli, Guillame
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Statistical analysis of the electric field measurements from the Rosetta spacecraft in the plasma environment of comet 67P/Churyumov-Gerasimenko2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Comets are a key to understanding the early stages of the solar system. They were hereat its formation and have not evolved ever since, which means they are our best shotat learning the processes that led to the formation of the solar system as we know ittoday. Yet, our knowledge about these bodies is very limited. They are far from theEarth and small, which makes it complicated and expensive to reach them. But thestudy of the chemistry and geology of comets is not the only goal of the scientific community.The plasma environment of these astronomical bodies could also give answersto many questions regarding the science of plasma physics, such as the interaction ofthe solar wind with plasmas. Answering some of these questions was an objectiveof the Rosetta Mission. Before its launch, only three space missions out of eight targettingcomets had plasma instruments onboard. Rosetta carried several instrumentsdesigned to analyse the plasma environment of comet 67P/Churyumov-Gerasimenko.We were able to perform a statistical analysis of the electric field spectrum in the vicinityof comet 67P/Churyumov-Gerasimenko. This allowed us to determine two regionsof high spectral activity using the two probes of the LAP instrument and to proposeseveral theories about the physical processes that were active.

  • Ekdahl, Victoria
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Raza, Josefina
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    A User-friendly Body Armor For Female2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish police have many problems with their body armor. The National Police have noticed that it particularly is the body armor made for women that they have the most problems with. Based on interviews with female police officers in Stockholm, it has emerged what the various problems with the armor is. Every one of the interviewees thought that it is far too warm with the body armor on, especially in summer. The material does not breathe well enough. Many of them also feel pain in the back and shoulders. It's too short so it chafes into the stomach. It becomes front heavy with extra plate in the front. Another problem many of them talked about was that the body armor is too tight so it becomes difficult to take deep breaths if they would have to do exhausting tasks such as running after someone. Because of this, and that it also gets so warm makes many of them unbuttoning the vest in the sides to ventilate and be able to expand the chest.The project aim is to answer the two questions, primary and secondary, that is compiled by FOI:

    1. How would body armor be designed if they were made for female staff?

    2. Is there a reason to question today’s standardized injury criterias if the users body weight is significantly reduced?

    The project has been an iterative process, and many methods have been used. Interviews and workshops have been made with the users to have their needs in focus. Brainstorming and prototyping has been made to easily view and understand the features of the vests. A combination brainstorming was done to see if the different concepts could be combined and thereby become even better. After that a concept selection was made using concept evaluation methods such as QFD and a Pugh matrix where the user requirements have been the foundation.The concept that was most liked by the users and also got best rating in the evaluations was the one that is the most flexible. It is the concept that allows the users to take deep breaths when exercising physical activity. It is the vest where the users do not have to unbutton in the side to let the chest expand. The vest also has better protection in side so even if the armor would be unbuttoned, it will still protect the police against projectiles.Various materials for the body armors outer casing have been investigated. A material that has a high breathability and can lead the moisture away is the material that has been sought. The chosen material is a natural functional material that can absorb moisture up to 30% of its weight and therefore is keeping the body dry.The answer to the secondary question has been discussed. Previous research has not drawn any conclusions about if the wearer's weight contributes to an increased or decreased injury from a projectile. Therefore, a discussion based on previous research done and conclusions have been drawn between them. The conclusion is that; Yes, there are reasons to doubt the injury criteria if the wearer's weight is significantly reduced.A conclusion drawn is that a closer relationship between the development of today's vests and user is needed.

  • Holgersson, Manfred
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Israelsson, Ingrid
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Användarvänlig skyddskåpa för rivningsrobotar2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Hydrodemolition is a technology similar to water jetting, and an alternative to traditional mechanical demolition with pneumatic drills. By firing highly pressurized water at a concrete surface, the top layer can be removed without damaging reinforcing bars or creating micro cracks deeper in the structure. The pressure created in the cavities causes the concrete to burst from within. The work environment is rough and noisy, with water, concrete and gravel shooting in every direction from the demolition area. Due to the hazardous nature of the work, a radio controlled and programmable robot is used. The robot is equipped with a protective hood to guard the engine, electronics and hydraulics from the harsh environment outside.This project has been a collaboration with Conjet AB; a company working with the development and production of hydrodemolition robots. The goal has been to design a new hood that is both user- and service-friendly with improved ergonomic and aesthetic values.Field studies of companies using hydrodemolition robots were made in order to investigate the user’s perspective. Contextual interviews have provided an insight into the users’ everyday tasks, and clearly demonstrate the importance of routine checks and daily service, in order to keep the robots’ components from breaking prematurely.The service- and usability have been improved by providing the hood with two large side hatches that opens by lifting them up. All daily points of control and service are accessible by simply opening the two hatches. When performing a thorough error search or service, the entire hood can be folded back, providing access to all internal components. The robot’s height (and hood) is kept to a maximum of 125 cm, improving its agility and enabling use in confined spaces such as parking garages or tunnels.Tests have been conducted on a full-scale model of the robot with the purpose to investigate the comfort of the user interface and the motion required to open the hatch, in order to verify the ergonomics and function of the concept.This project has been the first step in a product development process that will continue over a longer period of time. The following areas could be interesting to investigate and develop:

    - Test of air flow and temperature

    - Adaptation to electric engine

    - Control panel design and layout

    - Possible use of the hood on a lager robot

    - Tool design

  • Charles, Amal Prashanth
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Gonzalez Taylor, Claudio Alexander
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Development of a Method to Repair Gas Turbine Blades using Electron Beam Melting Additive Manufacturing Technology2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study focuses in using the electron beam melting additive manufacturing process to develop a framework to repair high performance gas turbine blades. These are currently fabricated using highly engineered super alloys, more specifically Inconel 738LC. The thesis focusses on the research on the current production methods of gas turbine blades, the operating environment inside the gas turbine, the most common failure modes as well as current methods of blade repair. This investigation includes studying the methods of production of metallic powders and the alloying effects of different elements in our required powder. A brief analysis was made to determine the economic viability for the usage of AM technology for mass production, and a proposition has been developed for the repair of turbine blades using additive manufacturing.

  • Linde, Linus
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Implementation of BECCS in a polygeneration system: - A techno-economic feasibility study in the district heating network of Stockholm2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The combination of Biomass Energy with Carbon Capture and Storage (BECCS) can reduce the level of CO2 in the atmosphere. It is, therefore, seen as an interesting tool in the CO2 abatement portfolio. In a Swedish context, BECCS could contribute to the goal of CO2 neutrality by 2045. This thesis aims to investigate the application of BECCS in the district heating system of Stockholm region with a case study at the energy utility Fortum Värme. The focus of the study is the technical and economic feasibility of such an application. The applicability of Fortum Värme´s plants to implement carbon capture is investigated together with costs and technical implications on each applicable plant and the district heating system as a whole. Three plants are deemed feasible for carbon capture with a cost of about 45€/tonne of captured CO2 (not including transport or storage). A model for transport of CO2 to promising storage sites in Sweden, Norway, and Denmark is constructed for transport by pipeline and ship. Ship transport is estimated to be the most cost-efficient option in all scenarios. The total cost for BECCS is calculated at 70-100€/tonne depending on size of emissions and distance to storage locations. Furthermore, the total cost is calculated to decrease by 10-25% if some current promising technologies for carbon capture reach maturity, a market for transport services of CO2 evolves, and a number of actors are sharing the costs for storage.Calculated costs are on a similar price level as other CO2 abatement strategies such as CCS in industries, biogas, and biodiesel in the vehicle fleet. If the cost is applied directly to the heat price, without any subsidies, it would increase the price of heat by 14-21%.The major challenge of BECCS in combined heat and power production, compared to other studies based on power production, is the seasonality of heat demand. The capacity of the carbon capture system will be oversized during the summer, or undersized during the winter. This is an optimization challenge which has to be further studied.

  • Ehrnberger, Karin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Product and Service Design.
    Räsänen, Minna
    Södertörns Högskola.
    Börjesson, Emma
    Högskolan i Halmstad.
    Hertz, Anne- Christine
    Högskolan i Halmstad.
    Sundbom, Cristine
    Konstfack.
    The Androchair: Performing Gynaecology through the Practice of Gender Critical Design2017In: The Design Journal, ISSN 1460-6965, Vol. 20, no 2, 1-19 p.Article in journal (Refereed)
    Abstract [en]

    This paper highlights the important role that design plays when it comes to women’s overall experi- ences of ther gynaecological examination. It exempli es how the examination can become renegotiable through the practice of a critical design. We will re ect this in the design of the contemporary gynaecological examination chair (GEC). We used women’s experiences as a starting point for the design of an Androchair (a conceptual male equivalent of the GEC), in order to make the experiences critically visible. Inspired by the view of the gynaecolog- ical examination as a performance where the Androchair is represented as a prop and was placed on a stage as a discussion object during a public seminar. The Androchair allowed for both critical and multiple readings of the GEC and through that, the gynaecology examination at large. Moreover, it stimulated a discussion about alternative ideas towards achieving a more positive experience. 

  • Karlsson, Frans
    et al.
    KTH, School of Technology and Health (STH).
    Kalmaru, Edvin
    KTH, School of Technology and Health (STH).
    Optimizing an Ultrasound Based Tissue Micro Engineering System: Optimering av ett Ultraljudsbaserat Cellmanipuleringssystem2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The usage of ultrasonic manipulation of cells enables a more in vivo-like study with maintained cell viability compared to ordinary systems based on 2D manipulation. The method can be applied for cell trapping and micro tissue engineering and has applications for medical and biological studies.  

    The current system used at the Department of Applied Physics, Royal Institute of Technology, needs characterization and optimization regarding its subsystems. This thesis has studied the setup in order to map the origins of heat generation, to improve the system arrangement. As a result, an overview of affecting factors has been presented. The thesis is based on temperature and bead measurements with and without the use of an impedance matching circuit and with/without amplifiers. It was found that the system could be optimized with a smaller and less expensive amplifier reducing the overall system costs. The thesis also resulted in a proposition for further work to optimize the system with respect to its subsystems. 

  • Ahlgren, Björn
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Subphotospheric dissipation in gamma-ray bursts observed by the Fermi Gamma-ray Space Telescope2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Gamma-ray bursts (GRBs) are the brightest events in the Universe, for a short time outshining the rest of the Universe combined, as they explode with isotropic equivalent luminosities up to $10^{54}$ erg s$^{-1}$. These events are believed to be connected to supernovae and to binary compact object mergers, such as binary neutron stars or neutron star -- black hole systems. The origin of the so-called prompt emission in GRBs remains an unsolved problem, although some progress is being made. Spectral analysis of prompt emission has traditionally been performed with the Band function, an empirical model with no physical interpretation, and it is just recently that physical models have started to be fitted to data. This thesis presents spectral analysis of GRB data from the Fermi Gamma-ray Space Telescope using a physical model for subphotospheric dissipation. The model is developed using a numerical code and implemented as a table model in {\scriptsize XSPEC}. Paper \rom{1} presents the model and provides a proof-of-concept of fitting GRB data with such a model. Specifically, two GRBs are fitted and compared with the corresponding Band function fits. In paper \rom{2}, a sample of 37 bursts are fitted with an extended version of the model and improved analysis tools. Overall, about a third of the fitted spectra can be described by the model. From these fits it is concluded that the scenario of subphotospheric dissipation can describe all spectral shapes present in the sample. The key characteristic of the spectra that are not fitted by the model is that they are very luminous. Within the context of the model, this suggests that the assumption of internal shocks as a dissipation mechanism cannot explain the full population of GRBs. Alternatively, additional emission components may required. The thesis concludes that subphotospheric dissipation is viable as a possible origin of GRB prompt emission. Furthermore, it shows the importance of using physically motivated models when analysing GRBs.

  • Public defence: 2017-03-24 10:00 FB53, Stockholm
    Riad, Stella
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical Particle Physics.
    Phenomenology of neutrino properties, unification, and Higgs couplings beyond the Standard Model2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The vast majority of experiments in particle physics can be described by the Standard Model of particle physics (SM). However, there are indications for physics beyond it. The only experimentally demonstrated problem of the model is the difficulty to describe neutrino masses and leptonic mixing. There is a plethora of models that try to describe these phenomena and this thesis investigates several possibilities for new models, both full theories and effective frameworks.

     

    The values of the parameters in a model are dependent on the energy scale and we say that the parameters run. The exact behavior of the running depends on the model and it provides a signature of the model. For a model defined at high energies it is necessary to run the parameters down to the electroweak scale in order to perform a comparison to the known values of observed quantities. In this thesis, we discuss renormalization group running in the context of extra dimensions and we provide an upper limit on the cutoff scale. We perform renormalization group running in two versions of a non-supersymmetric SO(10) model and we show that the SM parameters can be accommodated in both versions. In addition, we perform the running for the gauge couplings in a large set of radiative neutrino mass models and conclude that unification is possible in some of them.

     

    The Higgs boson provides new possibilities to study physics beyond the SM. Its properties have to be tested with extremely high precision before it could be established whether the particle is truly the SM Higgs boson or not. In this thesis, we perform Bayesian parameter inference and model comparison. For models where the magnitude of the Higgs couplings is varied, we show that the SM is favored in comparison to all other models. Furthermore, we discuss lepton flavor violating processes in the context of the Zee model. We find that these can be sizeable and close to the experimental limits.

  • Huldén, Joe
    KTH, School of Information and Communication Technology (ICT).
    Riktlinjer för mjukvarustartups2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Många innovativa mjukvaruföretag startas årligen. Flera med stor potential att konkurrera och utmana en hel industri med sina nytänkande idéer för att göra situationer enklare för en stor grupp av användare. Startups är termen som har blivit alltmer populärt och ibland så kallar man ett vanliga små och medel stora företag för startups.

    Den här uppsatsen reder ut begreppet startups genom att studiera mjukvaru startups företagets lärdomar på vägen från idé till börsintroduktion. Små mjukvaruföretag som snabbt skalas upp och kan växa från enstaka grundare till att ha flera tusen anställda med en global marknad. Studier sker genom intervjuer av grundare av några mjukvarustartup företag och litteraturläsning som beskriver startup företag från idé stadiet till börsintroduktion. Intervjuer analyseras och sker samtidigt som litteratur studer.

    Uppsatsen resulterar i en riktlinje baserad på lärdomar längs vägen av dom intervjuade mjukvaruföretag och litteratur studier av dom så kallade succé företagen som Uber, Facebook och AirBnB som har lyckats komma ut ur startups skede.

  • Westman, Nina
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Ek, Johan
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Arbetsmiljöns konsekvenser för arbetet på en mottagningsenhet på Migrationsverket: En experimentell fallstudie2016Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Today we know that a good working environment, both physical, organizational and social, provides opportunities for job satisfaction and productivity. At the same time it is also known that a poor working environment can affect a business adversely by poor productivity, reduced quality, increased absenteeism and staff turnover. Measuring the working environment consequences in economic terms, however, is difficult. More obstacles appear in the public sector with the difficulties in using the traditional measures of quality, productivity and efficiency to measure work.

    In this master thesis, we have through an explorative case study with semi-structured interviews, investigated what impact working environment factors, both physical, organizational and social, have on the work at a reception unit in the Swedish Migration Agency. Furthermore, we have also investigated how the work is affected by sick leave. To be able to investigate this, we have analyzed how work can be measured. An assessment of the negative impact the work environment and sick leave have on the operations, have subsequently been reported in both monetary terms and non-monetary terms.

    The results show that the employees feel that there are physical and organizational factors in the work environment that affect their work adversely. These factors express themselves into difficulty in concentrating, stress, frustration, and duplication of work, among the employees. This is considered to have consequences on the business in terms of negative impact on both quality and productivity. Sick leave is considered leading to stress and changes in priorities, which in turn, is expected tolead to production loss.

    The difficulties identified in previous research, on how to measure the impact of working environment on work in the public sector, is confirmed in this master thesis. One of the conclusions is that the work environment does affect the quality, productivity and efficiency. Another conclusion is that the person who makes an estimate of this impact, must be well versed in the business so that rationalization measures, that reflect the business goals, can be used. It also stated that consequences that may arise in an organization, as a result of shortcomings in the work, not always can be measured in monetary terms.

  • Riad, Stella
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical Particle Physics.
    Herrero-Garcia, Juan
    Wirén, Jens
    KTH, Superseded Departments, Physics.
    Full parameter scan of the Zee model: exploring Higgs lepton flavor violationManuscript (preprint) (Other academic)
    Abstract [en]

    We study the general Zee model, which includes an extra Higgs scalar doublet and a new singly-charged scalar singlet. Neutrino masses are generated at one-loop level, and in order to describe leptonic mixing, both the Standard Model and the extra Higgs scalar doublets need to couple to leptons (in a type-III two-Higgs doublet model), which necessarily generates large lepton flavor violating signals, also in Higgs decays. Imposing all relevant phenomenological constraints and performing a full numerical scan of the parameter space, we find that both normal and inverted neutrino mass orderings can be fitted, although the latter is disfavored with respect to the former. In fact, inverted ordering can only be accommodated if θ23 turns out to be in the first octant. A branching ratio for h→τμ of up to 10−2 is allowed, but it could be as low as 10−6. In addition, if future expected sensitivities of τ→μγ are achieved, normal ordering can be completely tested. Also, μeconversion is expected to strongly reduce the allowed parameter space, excluding completely inverted ordering. Furthermore, non-standard neutrino interactions are found to be smaller than 10−6, which is well below future experimental sensitivity. Finally, the results of our scan indicate that the masses of the additional scalars have to be below 2.5 TeV, and typically they are lower than that and therefore within the reach of the LHC and future colliders.

  • Riad, Stella
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical Particle Physics.
    Meloni, Davide
    Renormalization Group Running of Fermion Observables in an Extended Non-Supersymmetric SO(10) ModelManuscript (preprint) (Other academic)
    Abstract [en]

    We investigate the renormalization group evolution of fermion masses, mixings and quartic scalar Higgs self-couplings in an extended non-supersymmetric SO(10) model, where the Higgs sector contains the 10H, 120H, and 126H representations. The group SO(10) is spontaneously broken at the GUT scale to the Pati-Salam group and subsequently to the Standard Model (SM) at an intermediate scale MI. We explicitly take into account the effects of the change of gauge groups in the evolution. In particular, we derive the renormalization group equations for the different Yukawa couplings. We find that the computed physical fermion observables can be successfully matched to the experimental measured values at the electroweak scale. Using the same Yukawa couplings at the GUT scale, the measured values of the fermion observables cannot be reproduced with a SM-like evolution, leading to differences in the numerical values up to around 80 %. Furthermore, a similar evolution can be performed for a minimal SO(10) model, where the Higgs sector consists of the 10H and 126H representations only, showing an equally good potential to describe the low-energy fermion observables. Finally, for both the extended and the minimal SO(10) models, we present predictions for the three Dirac and Majorana CP-violating phases as well as three effective neutrino mass parameters.

  • Svensson, Christian
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Bayesian Filtering and Smoothing to Measure Damper Characteristics2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During the development of high performance damper products for vehicle applications, it is essential to measure the dampers’ characteristics to ensure their performance. Some of the measurements are performed in dynamometers. The dynamometer actuates the damper with a predefined position signal and measures the actual position and the resulting force. These measurements suffer from noise; the problem is especially bad if the signals are studied with respect to velocity. This is due to that the velocity is not directly measurable; it must be calculated from position by differentiation, which amplifies the noise. The purpose of this work was to improve these measurements by doing acomparison of different Bayesian filters and smoothers. The comparison included the Kalman filter, the extended Kalman filter, the unscented Kalman filter, the Rauch-Tung-Striebel smoother, the extended Rauch-Tung-Striebel smoother and the unscented Rauch-Tung-Striebel smoother. The smoothers are only applicable in offline applications, while the filters could be used in real time. The filters reduced the noise in the position signal and greatly reduced the noise in the velocity signal. The smoothers showed the same behaviors as the filters, but with much less noise. Only small improvements were visible in the force signal.

  • Diaz Martinez, Rene Alexander
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    A Library on the Robot Operating System (ROS) for Model Predictive Control implementation2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Model Predictive Control is a receding horizon control technique that is based on making predictions in the future for a determined number of steps, using a model of the system to be controlled. This thesis report is centered around Model Predictive Control (MPC) and its application. In this thesis, there are two main goals: firstly, is the development of a software structure that uses the properties of Object Oriented Programming (OOP) and the Robot Operative System (ROS) to ease the use of MPC applications. Secondly, the use and verification of the capabilities of MPC controllers in plants with fast dynamics, such as the quadrotor. A linearized model of the quadrotor is developed for the controller to perform the predictions, and the non-linear version is used to make a numerical simulator to test the application. The MPC software structure works as it successfully integrates information from the classes that represent the model and optimization method to solve the quadratic problem. The resulting MPC controller shows a good response when following simple trajectories in the presence of simulated noise. However, when more complex trajectories are used, a considerable offset from the reference is obtained. Such behavior mostly caused by the use of a very limited model, which demonstrates the considerable sensibility of the controller to the accuracy of the used model.

  • Chabo, Alexander
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Tysk, Peter
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Maximum Net-power Point Tracking of a waste heat recovery system2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    About 30% of the released energy of a truck’s fuel is waste heat in the exhaustsystem. It is possible to recover some of the energy with a waste heat recovery system that generates electricity from a temperature difference by utilising the Seebeck-effect. Two thermoelectric generators are implemented on a truck and utilises the exhaust gas as a heat source and the coolant fluid as a cold source to accomplish a temperature difference in the generators. The electricity is reintroduced to the truck’s electrical system and thus reducing the load on the electrical generator in the engine which results in lower fuel consumption. This thesis includes the construction of a function that maximises the netpowerderived from the system. The function developed is named Maximum Net Power Point Tracking (MNPT) and has the task of calculating reference values that the controllers of the system must achieve in order to obtain maximumnet-power. A simulation environment has been developed in Matlab/Simulink in order to design a control strategy to three valves and one pump. The system has been implemented on a engine control unit that has been mounted on a test rack. The engine control unit communicates through CAN to connected devices. The system has not been implemented on the truck due that all the physical components were not completed during the time of the thesis. A case study has been conducted and the results proves that the use of an MNPT-function allows up to 300% increase in regenerated net power into the trucks electrical system compared with no control algorithms, and up to 50% compared with static reference values.

  • Alrubaye, Aqeel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Shafiq, Twana
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    TOPVEX-ljud och vibrationsoptimering2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Pettersson, Kristoffer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Pilot Project Study for Industrial Surplus Heat Transportation2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Primary energy use in Sweden today can to a large extent be traced to manufacturing industries. In parallel, improved energy efficiency is a goal set out by Swedish authorities and the EU. One way to improve efficiency in the industry is to harvest the excess energy in form of heat that is currently going to waste in the various processes. This thesis has investigated the feasibility of employing a mobile thermal energy storage (M-TES), developed at KTH, as a method of transporting excess heat from a steel plant in Sandviken to a local hotel and conference centre. The M-TES performance had previously been determined on a small scale prototype, and the effects on performance and cost of up-scaling the M-TES for real use was studied theoretically. An estimation of the cost for up scaling the M-TES from its current laboratory scale to the intended large scale was obtained. The study concludes that the construction cost can be affected mainly by two parameters: the number of tubes and tube diameter inside the M-TES. Changes to the performance parameters of the M-TES, caused by varying these parameters, were investigated using theoretical correlations. It was found that performance of the M-TES can drastically change with changes to the design parameters. The exact changes in construction costs were not obtained, however, a cost effective design uses as few tubes as possible, meaning the tube diameter has to be increased. Using the theoretically based performance values, an M-TES operation was mapped towards two scenarios; one scenario where a greenhouse is supplied with heat, with comparatively low heating demand to the other scenario, where the greenhouse and hotel are both supplied. In the hotel-scenario, the M-TES complements the boiler that is already in place and provides heat for the hotel today. It was found that increased heating demand and number of heat deliveries significantly improved the economic performance of the M-TES system. The levelized cost of transported energy (LCOTE) was used as parameter for measuring this performance and LCOTE:s of 470 and 1380 SEK per MWh were found in the high and low demand scenarios, respectively. A sensitivity analysis showed that the M-TES itself is among the most influential parameters on the LCOTE, while also being deemed as the most uncertain in terms of cost and performance. It is recommended for future work that the MTES is investigated extensively with regard to design choice, performance and costs.

  • Deirmenci, Hazim
    KTH, School of Computer Science and Communication (CSC).
    Enabling Content Discovery in an IPTV System: Using Data from Online Social Networks2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Internet Protocol television (IPTV) is a way of delivering television over the Internet, which enables two-way communication between an operator and its users. By using IPTV, users have freedom to choose what content they want to consume and when they want to consume it. For example, users are able to watch TV shows after they have been aired on TV, and they can access content that is not part of any linear TV broadcasts, e.g. movies that are available to rent. This means that, by using IPTV, users can get access to more video content than is possible with the traditional TV distribution formats. However, having more options also means that deciding what to watch becomes more difficult, and it is important that IPTV providers facilitate the process of finding interesting content so that the users find value in using their services. In this thesis, the author investigated how a user’s online social network can be used as a basis for facilitating the discovery of interesting movies in an IPTV environment.

    The study consisted of two parts, a theoretical and a practical. In the theoretical part, a literature study was carried out in order to obtain knowledge about different recommender system strategies. In addition to the literature study, a number of online social network platforms were identified and empirically studied in order to gain knowledge about what data is possible to gather from them, and how the data can be gathered. In the practical part, a prototype content discovery system, which made use of the gathered data, was designed and built. This was done in order to uncover difficulties that exist with implementing such a system.

    The study shows that, while it is is possible to gather data from different online social networks, not all of them offer data in a form that is easy to make use of in a content discovery system. Out of the investigated online social networks, Facebook was found to offer data that is the easiest to gather and make use of. The biggest obstacle, from a technical point of view, was found to be the matching of movie titles gathered from the online social network with the movie titles in the database of the IPTV service provider; one reason for this is that movies can have titles in different languages.

  • Lundbäck, Kristoffer
    et al.
    KTH, School of Technology and Health (STH).
    Dahn, Leonardo
    KTH, School of Technology and Health (STH).
    Preliminary Evaluation of the Clinical Value of an Ultra-Wideband Radar Sensor for Heart Assessment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Heart dysfunction is a worldly widespread problem that currently is one of the leading causes of death. Studies indicate that many deaths related to cardiac dysfunction could have been prevented if discovered early. Contemporarily, ultrasound and electrocardiography are indispensable modalities for diagnostic purposes and analysis of cardiac function.

    The Ventricorder is an Ultra-Wideband radar sensor manufactured by the Norwegian company Novelda. Ventricorder has been shown to be able detect heart movements and breathing but its actual clinical value remains to be investigated. The Cardiac State Diagram (CSD) is a pre-clinical software tool for visualization of the heart's mechanical function. The CSD is confirmed by pilot studies to be able to constitute a basis for diagnosis and cardiac function assessment. Theoretically, the CSD is well suited to be used with the Ventricorder since the Ventricorder detects small changes over time and information about time events is all that is required for the creation of a CSD.

    Contemporarily, ultrasound tissue velocity imaging (TVI) is usually used for production of CSDs and in this master thesis we examined if the Ventricorder can be used to produce CSDs. This was done by mainly comparing velocity data from the Ventricorder with velocity data from temporally synchronized apical four-chamber images acquired with ultrasound TVI. The results indicate that there is an apparent correlation between these data sets and the Ventricorder should therefore be able to produce data that could constitute the basis for the production of a CSD. What remain now is to confirm these results statistically with a larger test group and to investigate whether all the time instants needed for the production of a CSD can be identified objectively.

  • Buizza, Giulia
    KTH, School of Technology and Health (STH).
    Classifying patients' response to tumour treatment from PET/CT data: a machine learning approach2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Early assessment of tumour response has lately acquired big interest in the medical field, given the possibility to modify treatments during their delivery. Radiomics aims to quantitatively describe images in radiology by automatically extracting a large number of image features. In this context, PET/CT (Positron Emission Tomography/Computed Tomography) images are of great interest since they encode functional and anatomical information, respectively. In order to assess the patients' responses from many image features appropriate methods should be applied. Machine learning offers different procedures that can deal with this, possibly high dimensional, problem.

    The main objective of this work was to develop a method to classify lung cancer patients as responding or not to chemoradiation treatment, relying on repeated PET/CT images. Patients were divided in two groups, based on the type of chemoradiation treatment they underwent (sequential or concurrent radiation therapy with respect to chemotherapy), but image features were extracted using the same procedure. Support vector machines performed classification using features from the Radiomics field, mostly describing tumour texture, or from handcrafted features, which described image intensity changes as a function of tumour depth. Classification performance was described by the area under the curve (AUC) of ROC (Receiving Operator Characteristic) curves after leave-one-out cross-validation. For sequential patients, 0.98 was the best AUC obtained, while for concurrent patients 0.93 was the best one. Handcrafted features were comparable to those from Radiomics and from previous studies, as for classification results. Also, features from PET alone and CT alone were found to be suitable for the task, entailing a performance better than random.

  • Hubert, Alexis
    KTH, School of Technology and Health (STH). Elekta AB.
    Spectroscopic Study of Radiation around the Leksell Gamma Knife for Room Shielding Applications2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Any center planning to install a Gamma Knife radiosurgery unit has to provide for an efficient shielding of the treatment room, to protect the patient, the staff and the public, against undesired radiation. The shielding barrier design is controlled by national and international recommendations; the reference documents for gamma ray radiotherapy facilities are the National Council on Radiation Protection and Measurements (NCRP) reports 49 and 151. However, some facts highlighted in this thesis point out that NCRP methods are ill-adapted to the Gamma Knife. Spectroscopic measurements were performed around the Gamma Knife with a Germanium detector. They revealed that the radiation field contains few high energy photons, is highly anisotropic, and that the leakage level is much lower than the NCRP estimation. These observations led to the development of a new approach to determine the necessary shielding, based on the actual and directly measurable radiation field around the unit. This method would reduce the shielding oversizing induced by the unsuitability of the NCRP recommendations for the Gamma Knife.

  • Cambazoglu, Volkan
    Uppsala universitet, Avdelningen för datorteknik.
    Protocol, mobility and adversary models for the verification of security2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The increasing heterogeneity of communicating devices, ranging from resource constrained battery driven sensor nodes to multi-core processor computers, challenges protocol design. We examine security and privacy protocols with respect to exterior factors such as users, adversaries, and computing and communication resources; and also interior factors such as the operations, the interactions and the parameters of a protocol.

    Users and adversaries interact with security and privacy protocols, and even affect the outcome of the protocols. We propose user mobility and adversary models to examine how the location privacy of users is affected when they move relative to each other in specific patterns while adversaries with varying strengths try to identify the users based on their historical locations. The location privacy of the users are simulated with the support of the K-Anonymity protection mechanism, the Distortion-based metric, and our models of users' mobility patterns and adversaries' knowledge about users.

    Security and privacy protocols need to operate on various computing and communication resources. Some of these protocols can be adjusted for different situations by changing parameters. A common example is to use longer secret keys in encryption for stronger security. We experiment with the trade-off between the security and the performance of the Fiat–Shamir identification protocol. We pipeline the protocol to increase its utilisation as the communication delay outweighs the computation.

    A mathematical specification based on a formal method leads to a strong proof of security. We use three formal languages with their tool supports in order to model and verify the Secure Hierarchical In-Network Aggregation (SHIA) protocol for Wireless Sensor Networks (WSNs). The three formal languages specialise on cryptographic operations, distributed systems and mobile processes. Finding an appropriate level of abstraction to represent the essential features of the protocol in three formal languages was central.

  • Markström, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Aktiv dämpning av ett skotarsäte med pneumatiska aktuatorer2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis an active seat suspension controller was implemented on a prototype forwarder seat undercarriage using only double acting pneumatic cylinders. The controller consists of an inner loop sliding mode controller (SMC) that controls the force and stiffness of the cylinders and an outer loop linear proportional position controller. The floor position is calculated using an accelerometer, this position is then used to minimize the seat movements. When subjected to a vertical floor disturbance with an amplitude of 20 mm and a frequency of 1Hz the best cylinder lowered the seat motion to -9.6 mm in the negative direction and 4.6 mm in the positive direction. This is a decrease of 64.5 % of the top to top motion. The performance was in the current setup believed to be limited by the available airflow. The results shows that the concept of double acting cylinders for active seat suspension is worth to investigate further where there are two main areas of interest to start with, the first is to consolidate the stability and performance of the existing SMC and the second is to determine an appropriate outer loop controller and its reference.

  • Public defence: 2017-03-17 10:00 Q2, Stockholm
    Huang, Yalin
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Economic Regulation Impact on Electricity Distribution Network Investment Considering Distributed Generation2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of EU’s actions against climate change is to meet 20% of energy consumption from renewable resources by the year 2020 when the project was started. Now this target has increased to at least 27% by the year 2030. In addition, given that the renewable resources are becoming more economical to generate electricity from and that these resources are distributed geographically, more and more distributed generation (DG) is connected to power distribution. The increasing share of DG in the electricity networks implies re-distribution of costs and benefits among distribution system operators (DSOs), customers and DG owners. How the costs and benefits will be allocated among them depends on the established economic regulation.

    The established economic regulation regulates the DSOs’ revenue and performances. The time when the DSOs are remunerated based on their actual costs has passed. Nowadays the economic regulation is in place to steer efficient investments. Network investments are no longer just to satisfy the load growth, or to higher the investments does not bring higher revenue. Network investments are incentivised by the regulation to be more efficient. Furthermore, the potential of DG to defer network investment is widely recognized. Ignoring this potential of DG may decrease DSOs’ efficiency. Last but not the least; network unbundling is a common practice in Europe. Ignoring the fact that DSOs and DG owners are different decision makers in studies can lead to inaccurate analysis.

    Driven by the target of a higher DG integration and more efficient investments in the unbundled distribution networks, proper economic regulations are needed to facilitate this change. The objective of this thesis is to evaluate the impact from regulations on distribution network investment considering DG integration. In other words, this thesis aims to develop methods assist regulators to design desirable regulations to encourage the DSOs to make the “smart” decisions. In order to achieve that, we propose a modelling approach to quantify the economic regulation impacts and the benefit of innovative investments. Regulations are encoded into the network investment model. The developed models, in other words, assist DSOs to make the “right” investment in the “right” place at the “right” time under the given regulation.

  • Larsson, Ida
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    God kvalitet på skyddsrondsarbetet inom byggindustrin: Framgångsfaktorer och utmaningar2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: The construction industry is a complex workplace, constant changes take place, and conditions can change quickly. The construction workers are at higher risk than many other businesses that suffer an accident or illness at work because of an increased risk for e.g. the use of machines or fall from height. In every workplace there should be conducted a prevention against risks through a systematic program of safety inspection. Companies in the construction sector have identified a need to streamline the systematic work which now Build Safe AB while addressing and created a digital tool Build Safe to streamline security. The study is part of a research project at KTH, where the aim was to evaluate the digital tool Build Safe in the construction industry.

    Aim: The purpose of the study is to investigate and describe the work on safety inspection in the construction industry and identifying success factors and challenges to achieve the quality and efficiency of the safety inspection work.

    Limitations: The author deals with safety inspection work in the construction industry confined to Sweden, the study does not address safety inspection work in other countries.

    Method: The study was conducted with a qualitative design with inductive approach. It conducted a participant observation, group interviews and four telephone interviews. A semi-structured interview guide was used in all interviews. All participation was voluntary, and all the collected data was anonymised.

    Results: The results showed that the identified key success factors that created the prerequisite for a well-functioning safety inspection work in the construction industry was the involvement and commitment of the company on safety inspection work. By using a digital tool better opportunities for a successful safety inspection work was also created, and with good planning and good communication before and after the safety inspection tour created the conditions for a good work environment.

  • Public defence: 2017-03-22 10:00 F3, Stockholm
    Fang, Yuan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Ions interacting with macromolecules: NMR studies in solution2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Specific ion effects, identified for more than hundred years, play an important role in a wide range of phenomena and applications. Several mechanisms such as direct ion interaction with molecules have been suggested to explain these effects, but quantitative experimental evidence remains scarce. Electrophoretic NMR (eNMR) has been emerging as a very powerful tool for studying molecular association and ionic transport in a variety of systems. Yet its potential in studying specific ion effect has been unexplored. In this thesis, eNMR was in part developed further as an analytical method and was in part used as one of the main techniques to study ions interacting with macromolecules in aqueous and non-aqueous solutions.

    The complexation of a large group of cations with poly ethylene oxide (PEO) in methanol was studied with eNMR. The binding of monovalent ions was demonstrated not to follow the Hofmeister order; multivalent cations except barium all showed negligible complexation. As a unifying feature, only cations with surface charge density below a threshold value were able to bind suggesting that ion solvation is critical. The binding mechanism was examined in greater detail for K+ and Ba2+ with oligomeric PEO of different chain lengths. Those two cations exhibited different binding mechanisms. K+ was found to bind to PEO by having at least 6 repeating units wrap around it while retaining the polymer flexibility. On the other hand, Ba2+ (and, to some extent, (BaAnion)+) needs a slightly shorter section to bind, but the molecular dynamics at the binding site slow considerably.

    The binding of anions with poly (N-isopropylacrylamide) in water was quantified at low salt concentration with eNMR and the binding affinity, though very weak, followed the Hofmeister order. This result indicates the non-electrostatic nature of this specific ion effects. The increase of binding strength with salt concentration is well described by a Langmuir isotherm.

    The specific ion binding to a protein, bovine serum albumin (BSA), was also studied at pH values where BSA has either net positive and negative charges. Our results show that anions have the same binding affinity irrespective of the surface charge while the binding strength of cations is reversed with the change in net surface charge. This indicates different binding mechanisms for cations and anions.

    The ionization of cellobiose in alkaline solutions was measured quantitatively by eNMR. The results show a two-step deprotonation process with increasing alkaline strength. Supported by results from 1H-13C HSQC NMR and MD simulation, ionization was proposed to be responsible for the improved solubility of cellulose in alkaline solution. eNMR was also used to characterize the effective charge of tetramethylammonium ions in a variety of solvents. In solvents of high polarity, the results agree well with predictions based on Onsager’s limiting law but for nonpolar solvents deviations were found that were attributed to ion pair formation. 

  • Fakhfakh, Sarra
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Solving inverse problems in thermal engineering using a surrogate model2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Through either measured or computed experimental data, inverse problems aim to determine parameters not straightforwardly given by measure. An inverse problem results in an optimization problem that requires many simulations of the direct problem which computations can be costly. One approach is to replace the reference model by a reduced model. A reduced model or surrogate is built by a statistical learning method (a theory on how to characterize the behaviour of a function based on observed data). In this case, uncertainties have a bigger effect on the problem and the errors introduced by the surrogate can significantly alter the convergence process. Furthermore, it is well known that the determination of input parameters via observed ones is an ill conditioned problem. As a result, the slightest measuring errors can engender tremendous gaps in the values of the reconstructed parameters, thus ruining their use. We can remedy that by adding a penalty in the optimization problem which would ensure a better stability during its resolution.

    Identification problems are here solved using a surrogate model. The issues of this approach on the resolution of the reference model are evaluated. Other specific substitution models known to be less reliable but better suited to inverse problems due to a regularization expression are constructed.

    Classical optimization methods including a penalty for the resolution of identification problems are implemented. The impact of the reliability of the surrogate model on the robustness and accuracy of the resolution is then carried out. In order to improve the surrogate model fidelity, sequential enrichment of the design of experiments is applied. Finally, the methodology is tested on a simplified thermal engineering example: the one dimensional heat conduction problem.

  • Botkina, Darya
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Xu, Meixin
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    ISO ToolMaker application development2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the rapid development of manufacturing industry, there is an increasing need for different industries to communicate, exchange and share information. While, the diversity of terms being used among different organizations makes the communication hard to proceed. Due to this reason, Sandvik Coromant decided to initiate development of a new international standard ISO 13399 under the title Cutting tool data representation and exchange. The standardis developed by Sandvik Coromant, KTH Royal Institute of Technology in Stockholm, French Cetim (technical centre for mechanical engineers) and other organizations in the metal cutting sector. (Sandvik Coromant)ISO 13399 has been developed for years, and it has reached a stage to be tested and verified. In 2014, Sandvik starts a new project of developing an application called ISO ToolMaker for verifying and validating the development and implementation specification of ISO 13399. By2016, the framework of this application has been set up. Since the software development is still at the primary stage, there are plenty of issues need to be settled afterwards. Therefore, the purpose of this thesis is to promote the reform of ISO ToolMaker, adjusting existing undesired functions, adding new modules for advanced usage, and reorganize the software structure for continuous improvement. By conducting the literature research and interviewing the staff in Sandvik Coromant, an action plan was made, and a systematic method was applied to guide the procedures. Compare to the previous application, the final version has three significant advantages ‐ an extra store function for items and assemblies, a more rigorous logical connection and a one‐click output mode and, in addition, the text‐info for guiding each step and the detail design of the software. All the aspects make it a superior and user‐friendly application to work with.

  • Genette, Gérard
    EHESS.
    Fiktionell berättelse, faktisk berättelse1993In: Tidskrift för litteraturvetenskap, ISSN 1104-0556, E-ISSN 2001-094X, , 19 p.28-45 p.Article in journal (Other academic)
  • Jilltoft, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Westman, Emil
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Early Stage Venture Capital in Emerging Markets: Case study Kenya2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study investigates which mechanisms that needs to be improved in order to facilitate more early stage venture capital (VC) investments on emerging markets. For this purpose a qualitative case study of the VC scene in Nairobi, Kenya was performed. The study has a 'best-practice' viewpoint aiming to provide insights to venture capitalists on how to operate within the Kenyan startup scene. The empirical findings of the case study indicate that the region is still an untapped market for VC investments, partly as a result of an equity gap towards early stage startups.

    The success stories of mobile money transfer startup M-Pesa and information crowdsourcing startup Ushahidi ignited the Nairobi startup scene in 2008 and enabled the city to become the startup hub of East Africa. M-Pesa has not only demonstrated that it is possible to develop highly successful tech companies but also created a payment infrastructure that facilitates for future startups. In light of this, Kenya presents an interesting case study, as the market poses opportunities as well as challenges.

    Our result indicates that the present equity gap hampers early stage VC and is derived from a lack of experience and knowledge from investor’s and entrepreneurs. In conclusion, the entire "ecosystem" needs to be aligned in order to diminish the gap; VC’s must adopt a more hands on approach in their investment strategy, entrepreneurs need a global mindset, development financial institutions (DFIs) and private equity (PE) funds should act more catalytic in early stage rounds and governmental entities should focus on enhancing entrepreneurial education and the overall economic performance. These alignments will in the long run lead to a more effective startup and VC scene and should be applicable on similar markets. However, specific adjustments for the subject market should always be considered before implemented.

  • Zhang, Yu
    KTH, School of Electrical Engineering (EES).
    Implementation of Reliability Centered Asset Management method on Power Systems2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Asset management is getting increasingly important in nearly all fields, especially inthe electric power engineering. It is mainly due to the following two reasons. First isthe high investment cost include the design cost, construction cost, equipment costand the high maintenance cost. Another reason is that there is always a high penaltyfee for the system operator if an interruption happened in the system. Besides, due tothe deregulation of electricity market in these years, the electricity utilities are payingmore attentions to the investment and maintenance cost. And one of their main goalsis to maximize the maintenance performance. So the challenge for the systems is toprovide high-reliability power to the customs and meanwhile be cost-effective for thesuppliers. Reliability Centered Asset Management (RCAM) is one of the bestmethods to solve this problem.The basic RCAM method is introduced first in this thesis. The model includes themaintenance strategy definition, the maintenance cost calculation and an optimizationmodel. Based on the basic model some improvements are added and a new model isproposed. The improvements include the new improvement maintenance strategy,increasing failure rate and a new objective function. The new model is also able toprovide a time-based maintenance plan.The simulation is done to a Swedish distribution system-Birka system by GAMS. Theresults and a sensitivity analysis is presented. A maintenance strategy for 58components and in 120 months is finally found. The impact on the changing failurerate is also shown for the whole peroid.

  • Von Treskow, Carl
    KTH, School of Information and Communication Technology (ICT).
    Unaltered Blinking in Single Silicon Oxidized Nanocrystals when X-ray Irradiated2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Quantum dots exhibit a range of interesting and useful properties linked to their elemental composition, crystal structure, size and shape. Two such properties is the work function and blinking frequency. Tests on several different quantum dot types have shown that x-ray radiation will alter these factors; with increasing doses "bleaching" the dots and making them permanently dark. There are several competing theories to explain this behavior and a lot of materials systems that have not been investigated yet. One such unexplored material is oxidized silicon NCs. This work found no consistent change in work function or blinking frequency after an X-ray dose of ~272 000 Gy absorbed by the SiO2. Individual dots changed between PL measurements but as a whole the sample remained statistically unchanged.

  • Bylund, Mats
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematics (Div.).
    Stability in Hamiltonian Systems: KAM stability versus instability around an invariant torus2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In his ICM-54 lecture, Kolmogorov introduced a now fundamental result regarding the persistence of a large (in the measure theoretic sense) set of invariant tori, in a certain category of almost-integrable Hamiltonian systems. 44 years later, in his ICM-98 talk, Herman conjectured that given any analytic Hamiltonian system with an invariant diophantine torus, this torus will always be accumulated by a positive measure set of invariant KAM tori, i.e. it will be KAM stable.

    In this thesis, we build upon recent results and provide a counterexample in three degrees of freedom to KAM stability around an invariant torus, in the category of smooth Hamiltonian systems. The thesis is self-contained in the sense that it also includes a brief introduction to Hamiltonian systems, as well as an exposition of Kolmogorov's classic result.

  • Eliwi, Roa
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Eliwi, Sheima
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    The tweeting machine – CNC-PLC interface2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The development and use of computerized machining tools and equipment within the manufacturing area has opened the door to an abundance of data. But, there is a need to structure the data, make it generic and accessible and define ways of communication in order to maximize the benefits of its utilization. The Line Information System Architecture (LISA) project aims to create an information architecture which aids in capturing and understanding this data by tackling the above mentioned requirements.This thesis is intended to implement the Tweeting machine concept, tweeting useful machining information during operations. The data will be transferred to the LISA architecture, providing users with the possibility to subscribe to the information. Offering useful and structured real-time data, which can be used to e.g. aid in analyzing and decreasing processing flaws, increasing quality, decision making. The solution has been tested and verified using transport communication protocol (TCP) and open communication protocol (OPC) connections. Which have been applied to the 5-axis machining tool HERMLE C 50 U, in the Department of Production Engineering at the Royale Institute of Technology, Stockholm, Sweden.The thesis report will firstly provide the reader with necessary background information regarding the computerized numerical control (CNC) machine used as well as its configuration. Followed by information regarding OPC, TCP and Industrial Ethernet as well as a run through of the operational software used. The programming of the solution is provided in a relatively detailed manner with the hopes that it will provide a good basis for future development of this implementation.

  • Söder, Lennart
    KTH, Superseded Departments, Electric Power Systems.
    Vindkraftens tillgänglighet vid hög elförbrukning1987Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Vindkraftens tillgänglighet vid hög elförbrukning har undersökts for 10 förbrukningstoppar under tidsperioden vintern 1979/80 - vintern 1986/87. En antagen installation av vindkraftverk vid 3 platser i Sverige har studerats. Genomsnittseffekten for dessa vindkraftverk vid studerade förbrukningstoppar skulle ha varit ungefär densamma som genomsnittseffekten under hela perioden jan 1980- dec 1985. Hypotesen "Det är vindstilla vid förbrukningstoppar" kan uteslutas. Hypotesen "Det är ofta vindstilla vid förbrukningstoppar kan inte bekräftas. Resultaten tyder på att det inte föreligger någon större skillnad mellan vindstyrkan vid förbrukningstoppar och vindstyrkan under det övriga året.

  • Bladh, Mikael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Ladufjäll, Erik
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Tryckfördelning över skivbromsbelägg: En kontaktstudie med finita element metoden2007Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Common problems with disc brakes are brake squeal, brake dust and uneven wear. These problems do not only affect the performance of the brake but they also have a negative effect on the environment. To solve these problems the understanding and knowledge of the contact between brake pad and rotor is essential.The project Pressure distribution between brake pad and rotor has studied the pressure distribution in an existing disc brake based on the finite element method. A static model with linear elastic material has been used and thermal effects have not been taken into account. The aim of the project is to answer the following questions:• Which model should be used in a finite element program to get good results?• Which effects will the composition of the brake pad have on the contact?• How will the results vary depending on how the force is transferred to the brake pad?• How will deformation in the brake calliper affect the contact?• How does sliding between brake pad and rotor affect the contact?Which model to use when performing contact simulations depends on your interest in the contact. In this case, where the global pressure distributions have been studied, results show that the mesh is important, it’s also important that frictional effects have been taken into account.Results show that external factors have the most effect on the pressure distribution, for example how the force is transferred to the brake pad and deformation in the brake calliper. The property of the brake pad that affects the pressure distribution the most is the orthotropic behaviour which will even the pressure over the brake pad.A short study of sliding in the contact between the brake pad and the rotor shows that sliding will redistribute the pressure against the front of the pad.