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  • 1. A, Ahmad
    et al.
    G, Bianchi
    L, Bernstein
    G, Fodor
    G, Pujolle
    LB, Sung
    YD, Yao
    QoS support and service differentiation in wireless networks2004In: International Journal of Communication Systems, ISSN 1074-5351, E-ISSN 1099-1131, Vol. 17, no 6, p. 507-512Article in journal (Refereed)
  • 2.
    A Asif, Farazee M
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Circular Manufacturing Systems: A development framework with analysis methods and tools for implementation2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The society today lives on the philosophy of ‘take-make-use-dispose.’ In the long run, this is not sustainable as the natural resources and the waste carrying capacity of the earth are limited. Therefore, it is essential to reduce dependency on the natural resources by decoupling the growth from the consumption. In this venture, both the society and the manufacturing industry have a vital role to play. The society needs to shift towards Circular Economy that rests upon the philosophy of ‘take-make-use-reuse’ and the manufacturing industry has to be a major stakeholder in this shift. Despite being proven to be both economically and environmentally beneficial, successful examples of circular systems are few today. This is primarily due to two reasons; firstly, there is a lack of systemic and systematic approach to guide industries and secondly, there is a lack of analysis methods and tools that are capable of assessing different aspects of circular manufacturing systems. Taking on to these challenges, the objective of this research is to bring forward a framework with methods and decision support tools that are essential to implement circular manufacturing systems. The initial conceptual framework with the systemic approach is developed based on extensive review and analysis of research, which is further adapted for industrial implementation. Systematic analysis methods, decision support and implementation tools are developed to facilitate this adaptation. This development has been supported by four cases from diverse manufacturing sectors. Behind each decision support tool, there are analysis methods built upon mainly system dynamics principles. These tools are based on simulation platforms called Stella and Anylogic. Among other things, these tools are capable of assessing the performance of closed-loop supply chains, consequences of resource scarcity, potential gains from resource conservation and overall economic and environmental performance of circular manufacturing systems.

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  • 3.
    A Asif, Farazee M
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Rashid, Amir
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Bianchi, Carmine
    University of Palermo (ITALY) Faculty of Political Sciences - Department of International Studies .
    Nicolescu, Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Performance analysis of the closed loop supply chain2012In: Journal of Remanufacturing, ISSN 2210-4690, Vol. 2, no 4Article in journal (Refereed)
    Abstract [en]

    Purpose

    The question of resource scarcity and emerging pressure of environmental legislations has brought a new challenge for the manufacturing industry. On the one hand, there is a huge population that demands a large quantity of commodities; on the other hand, these demands have to be met by minimum resources and pollution. Resource conservative manufacturing (ResCoM) is a proposed holistic concept to manage these challenges. The successful implementation of this concept requires cross functional collaboration among relevant fields, and among them, closed loop supply chain is an essential domain. The paper aims to highlight some misconceptions concerning the closed loop supply chain, to discuss different challenges, and in addition, to show how the proposed concept deals with those challenges through analysis of key performance indicators (KPI).

    Methods

    The work presented in this paper is mainly based on the literature review. The analysis of performance of the closed loop supply chain is done using system dynamics, and the Stella software has been used to do the simulation. Findings The results of the simulation depict that in ResCoM; the performance of the closed loop supply chain is much enhanced in terms of supply, demand, and other uncertainties involved. The results may particularly be interesting for industries involved in remanufacturing, researchers in the field of closed loop supply chain, and other relevant areas. Originality The paper presented a novel research concept called ResCoM which is supported by system dynamics models of the closed loop supply chain to demonstrate the behavior of KPI in the closed loop supply chain.

  • 4.
    A Atlasov, Kirill
    et al.
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Felici, Marco
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Karlsson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gallo, Pascal
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Rudra, Alok
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Dwir, Benjamin
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Kapon, Eli
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    1D photonic band formation and photon localization in finite-size photonic-crystal waveguides2010In: OPTICS EXPRESS, ISSN 1094-4087, Vol. 18, no 1, p. 117-122Article in journal (Refereed)
    Abstract [en]

    A transition from discrete optical modes to 1D photonic bands is experimentally observed and numerically studied in planar photonic-crystal (PhC) L-N microcavities of length N. For increasing N the confined modes progressively acquire a well-defined momentum, eventually reconstructing the band dispersion of the corresponding waveguide. Furthermore, photon localization due to disorder is observed experimentally in the membrane PhCs using spatially resolved photoluminescence spectroscopy. Implications on single-photon sources and transfer lines based on quasi-1D PhC structures are discussed.

  • 5.
    A Elhassan, Amro
    KTH, School of Electrical Engineering (EES).
    Building automation and control2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
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  • 6. A, Eriksson
    et al.
    G, Fodor
    A middlebox control plane framework for wireless and mobile IP networks2004In: 2004 International Conference on Parallel Processing Workshops, 2004 (ICPP 2004 Workshops) / [ed] IEEE, New York: IEEE conference proceedings, 2004, p. 322-329Chapter in book (Other academic)
    Abstract [en]

    In wireless and mobile IP networks there is a need to support a set of functions that are related to wireless QoS provisioning, resource optimizations, mobility and security management and operator policy enforcement. These requirements have lead to the frequent usage of so called middleboxes including header/payload compressors, performance enhancement proxies, tunnel endpoints, packet filters and redirectors, QoS schedulers and others. Unfortunately, the increasing usage of these types of devices often leads to undesirable artifacts called feature interactions. In this paper we propose a framework that aims to coordinate the operation of middleboxes such that feature interactions are avoided. The three main ideas are (1) the separation of the control plane from the distributed network nodes, (2) the usage of a middlebox function independent horizontal protocol that allows mobile hosts to communicate their desired service requests to the network and (3) the usage of a vertical protocol between the network control and user planes. We present two examples in which this framework helps eliminate the risk for feature interactions. We comment on the relationship between the end-to-end principle and this framework. Finally, we discuss how future middleboxes can fit into this framework.

  • 7. A., F.
    NA2019Conference paper (Other academic)
  • 8.
    A, Fredrik
    et al.
    KTH, School of Electrical Engineering (EES).
    Forsberg, A
    KTH, School of Electrical Engineering (EES).
    Forsén, Tobias
    KTH, School of Electrical Engineering (EES).
    Tracking Using Wireless Camera Networks2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
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  • 9.
    A Herrera, I
    et al.
    Norwegian University Science and Technology NTNU.
    Woltjer, Rogier
    Linköping University, Department of Computer and Information Science, CSELAB - Cognitive Systems Engineering Laboratory. Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, Human-Centered systems.
    Comparing a multi-linear (STEP) and systemic (FRAM) method for accident analysis2010In: RELIABILITY ENGINEERING and SYSTEM SAFETY, ISSN 0951-8320, Vol. 95, no 12, p. 1269-1275Article in journal (Refereed)
    Abstract [en]

    Accident models and analysis methods affect what accident investigators look for, which contributory factors are found, and which recommendations are issued. This paper contrasts the Sequentially Timed Events Plotting (STEP) method and the Functional Resonance Analysis Method (FRAM) for accident analysis and modelling. The main issue addressed in this paper is the comparison of the established multi-linear method STEP with the new systemic method FRAM and which new insights the latter provides for accident analysis in comparison to the former established multi-linear method. Since STEP and FRAM are based on a different understandings of the nature of accidents, the comparison of the methods focuses on what we can learn from both methods, how, when, and why to apply them. The main finding is that STEP helps to illustrate what happened, involving which actors at what time, whereas FRAM illustrates the dynamic interactions within socio-technical systems and lets the analyst understand the how and why by describing non-linear dependencies, performance conditions, variability, and their resonance across functions.

  • 10. A. Hosseini, V.
    et al.
    Karlsson, L.
    Örnek, Cem
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Swerea KIMAB AB.
    Reccagni, P.
    Wessman, S.
    Engelberg, D.
    Microstructure and functionality of a uniquely graded super duplex stainless steel designed by a novel arc heat treatment method2018In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 139, p. 390-400Article in journal (Refereed)
    Abstract [en]

    A novel arc heat treatment technique was applied to design a uniquely graded super duplex stainless steel (SDSS), by subjecting a single sample to a steady state temperature gradient for 10 h. A new experimental approach was used to map precipitation in microstructure, covering aging temperatures of up to 1430 °C. The microstructure was characterized and functionality was evaluated via hardness mapping. Nitrogen depletion adjacent to the fusion boundary depressed the upper temperature limit for austenite formation and influenced the phase balance above 980 °C. Austenite/ferrite boundaries deviating from Kurdjumov–Sachs orientation relationship (OR) were preferred locations for precipitation of σ at 630–1000 °C, χ at 560–1000 °C, Cr2N at 600–900 °C and R between 550 °C and 700 °C. Precipitate morphology changed with decreasing temperature; from blocky to coral-shaped for σ, from discrete blocky to elongated particles for χ, and from polygonal to disc-shaped for R. Thermodynamic calculations of phase equilibria largely agreed with observations above 750 °C when considering nitrogen loss. Formation of intermetallic phases and 475 °C-embrittlement resulted in increased hardness. A schematic diagram, correlating information about phase contents, morphologies and hardness, as a function of exposure temperature, is introduced for evaluation of functionality of microstructures.

  • 11.
    A. M. Naiini, Maziar
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Horizontal Slot Waveguides for Silicon Photonics Back-End Integration2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents the development of integrated silicon photonic devices. These devices are compatible with the present and near future CMOS technology. High-khorizontal grating couplers and waveguides are proposed. This work consists of simulations and device design, as well as the layout for the fabrication process, device fabrication, process development, characterization instrument development and electro-optical characterizations.

    The work demonstrates an alternative solution to costly silicon-on-insulator photonics. The proposed solution uses bulk silicon wafers and thin film deposited waveguides. Back-end deposited horizontal slot grating couplers and waveguides are realized by multi-layers of amorphous silicon and high-k materials.

    The achievements of this work include: A theoretical study of fully etched slot grating couplers with Al2O3, HfO2 and AIN, an optical study of the high-k films with spectroscopic ellipsometry, an experimental demonstration of fully etched SiO2 single slot grating couplers and double slot Al2O3 grating couplers, a practical demonstration of horizontal double slot high-k waveguides, partially etched Al2O3 single slot grating couplers, a study of a scheme for integration of the double slot Al2O3  waveguides with selectively grown germanium PIN photodetectors, realization of test chips for the integrated germanium photodetectors, and study of integration with graphene photodetectors through embedding the graphene into a high-k slot layer.

    From an application point of view, these high-k slot waveguides add more functionality to the current silicon photonics. The presented devices can be used for low cost photonics applications. Also alternative optical materials can be used in the context of this photonics platform.

    With the robust design, the grating couplers result in improved yield and a more cost effective solution is realized for integration of the waveguides with the germanium and graphene photodetectors.

     

     

     

     

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    Thesis
  • 12.
    A Monfared, Behzad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Design and Construction of a Small Ammonia Heat Pump2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In view of the fact that most of the synthetic refrigerants, in case of leakage or release, are harmful to the environment by contributing in global warming or depleting stratospheric ozone layer, many research works have been done recently to find alternative refrigerants posing no or negligible threat to the environment. Among alternative refrigerants, ammonia, a natural refrigerant with zero Global Warming Potential (GWP) and Ozone Depletion Potential (ODP), can be a sensible choice.Although ammonia has been used for many years in large industrial systems, its application in small units is rare. In this project a small heat pump with about 7 kW heating capacity at -5 °C and +40 °C evaporation and condensation temperatures is designed and built to work with ammonia as refrigerant. The heat pump is expected to produce enough heat to keep a single-family house warm in Sweden and to provide tap hot water for the house. After successful completion of this project, it is planned to install the heat pump in a house to test it throughout a heating season to study its performance in real working conditions.Since ammonia is flammable and toxic in high concentrations, the refrigerant charge is tried to be kept low in the heat pump to reduce the risk of fire or poisoning in case of unwanted release of refrigerant to the surroundings. The compact design of the heat pump helps reducing the refrigerant charge. Besides, considering the limited space normally reserved for installation of a heat pump in a house, the compact design of the heat pump is necessary.

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    B A Monfared 2010_Design and Construction of a Small Ammonia Heat Pump_MSc Thesis
  • 13.
    A Monfared, Behzad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Magnetic Refrigeration for Near Room-Temperature Applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Refrigeration plays a crucial role in many different sectors and consumes about 17% of the electricity produced globally. This significant energy consumption implies large share of refrigeration in primary energy consumption and other environmental impacts. In addition to the environmental impacts associated with energy consumption, the vapor-compression systems contribute in global warming due to the release of their gaseous refrigerants into the atmosphere. As an alternative technology for near room-temperature applications, magnetic refrigeration is proposed by some researchers to eliminate the release of gaseous refrigerants into the atmosphere and to reduce the energy consumption. This thesis is a compilation of a number of studies done on magnetic refrigeration for room-temperature applications.

    In the first study, the environmental impacts associated to magnetic refrigeration are looked at closely through a life cycle assessment. The life cycle assessment indicates that because of the environmental burdens related to the rare-earth materials used in magnetic refrigeration, the reduction in the environmental impacts is not guaranteed by switching to magnetic refrigeration technology. Accordingly to avoid the extra environmental impacts the magnetic refrigeration systems should use magnetic materials frugally, which requires an optimized design. In addition, operation with higher efficiency compared to vapor-compression systems is necessary to have environmental advantages, at least in some impact categories.

    A practical method to optimize the design of magnetic refrigeration systems, e.g. to have a compact design or high efficiency, is utilizing a flexible software model, with which the effect of varying different parameters on the performance of the system can be simulated. Such a software model of the magnetic refrigeration system is developed and validated in this project. In developing the model one goal is to add to the precision of the simulated results by taking more details into consideration. This goal is achieved by an innovative way of modeling the parasitic heat transfer and including the effect of the presence of magnetocaloric materials on the strength of the field created by the magnet assembly. In addition, some efforts are made to modify or correct the existing correlations to include the effect of binding agents used in some active magnetic regenerators. Validation of the developed software model is done using the experimental results obtained from the prototype existing at the Department of Energy Technology, KTH Royal Institute of Technology.

    One of the parameters that can be modified by the developed software model is the choice of the magnetocaloric materials for each layer in a layered active magnetic regenerator. Utilizing the software model for optimizing the choice of the materials for the layers reveals that materials with critical temperatures equal to the cyclic average temperature of the layers in which they are used do not necessarily result in the desired optimum performance. In addition, for maximizing different outputs of the models, such as energy efficiency or temperature lift sustained at the two ends of the regenerators, different choice of materials for the layers are needed. Therefore, in other studies seeking to improve one of the outputs of a system, the choice of the transition or critical temperatures of the materials for each layer is an additional parameter to be optimized.

    The prototype existing at the Department of Energy Technology, KTH Royal Institute of Technology, was initially designed for replacing the vapor-compression system of a professional refrigerator. However, it could not fulfil the requirements for which it was initially designed. The aforementioned developed simulation model is used to see how much the choice of the materials, size of the particles, and number of layers can enhance the performance while the operation frequency and flow rate of the heat transfer fluid are at their optimum values. In other words, in that study the room for improvement in the performance without applying major changes in the system such as the geometry of the regenerator, which implies redesigning the whole magnet assembly, is investigated. In the redesign process the effect of binding agent and the limitations associated to different properties of it is also investigated theoretically. Nevertheless, the study did not show that with keeping the geometry of the regenerators and the currently existing magnetocaloric materials the initial goals of the prototype can be achieved.

    In the next study more flexible choice of geometries and magnetocaloric materials are considered. In fact, in this study it is investigated how much the magnetocaloric materials need to be improved so that magnetic refrigeration systems can compete with vapor-compression ones in terms of performance. For the two investigated cases, the magnetic-field dependent properties of the currently existing materials are enough provided that some other issues such as low mechanical stability and inhomogeneity of the properties are solved. Nevertheless, for more demanding design criteria, such as delivering large cooling capacity over a considerable temperature span while the magnetic materials are used sparingly, the magnetic-field dependent properties need to be enhanced, as well.

    A less explored area in room-temperature magnetic refrigeration is the subject of another study included in the thesis. In this study, solid-state magnetic refrigeration systems with Peltier elements as heat switches are modeled. Since the Peltier elements consume electricity to pump heat, the modeled systems can be considered hybrid magnetocaloric-Peltier cooling systems. For such systems the detailed transient behavior of the Peltier elements together with layers of magnetocaloric materials are modeled. The mathematical model is suitable for implementation in programing languages without the need for commercial modeling platforms. The parameters affecting the performance of the modeled system are numerous, and optimization of them requires a separate study. However, the preliminary attempts on optimizing the modeled system does not give promising results. Accordingly, focusing on passive heat switches can be more beneficial.

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  • 14.
    A. Mouris, Boules
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering. KTH Royal Institute of Technology.
    Ghauch, Hadi
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Network and Systems Engineering.
    Thobaben, Ragnar
    Jonsson, B. Lars G.
    KTH, Superseded Departments (pre-2005), Electromagnetic Theory. KTH, Superseded Departments (pre-2005), Electrical Systems. KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Multi-tone Signal Optimization for Wireless Power Transfer in the Presence of Wireless Communication Links2020In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248Article in journal (Refereed)
    Abstract [en]

    In this paper, we study optimization of multi-tone signals for wireless power transfer (WPT) systems. We investigate different non-linear energy harvesting models. Two of them are adopted to optimize the multi-tone signal according to the channel state information available at the transmitter. We show that a second-order polynomial curve-fitting model can be utilized to optimize the multi-tone signal for any RF energy harvester design. We consider both single-antenna and multi-antenna WPT systems. In-band co-existing communication links are also considered in this work by imposing a constraint on the received power at the nearby information receiver to prevent its RF front end from saturation. We emphasize the importance of imposing such constraint by explaining how inter-modulation products, due to saturation, can cause high interference at the information receiver in the case of multi-tone signals. The multi-tone optimization problem is formulated as a non-convex linearly constrained quadratic program. Two globally optimal solution approaches using mixed-integer linear programming and finite branch-and-bound techniques are proposed to solve the problem. The achieved improvement resulting from applying both solution methods to the multi-tone optimization problem is highlighted through simulations and comparisons with other solutions existing in the literature.

  • 15.
    A. Mouris, Boules
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering. KTH Royal Institute of Technology.
    Kolitsidas, Christos
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Thobaben, Ragnar
    A Dual-Polarized Multi-Antenna Structure for Simultaneous Transmission of Wireless Information and Power2019In: A Dual-Polarized Multi-Antenna Structure for Simultaneous Transmission of Wireless Information and Power, IEEE, 2019Conference paper (Refereed)
    Abstract [en]

    In this paper, a dual-polarized multi-antenna structure is designed at 2.45 GHz with the goal of allowing simultaneous transmission of wireless information and power. Differential feeding was used to minimize the mutual coupling due to radiation leakage in addition to a mushroom-type EBG structure for suppressing the surface waves. Simulation results for the proposed structure show a mutual coupling level lower than -40 dB between the information transmitting antenna and the power transmitting antennas for both polarizations. The isolation level between the antennas is improved by at least 22 dB and 14 dB for the E-plane and H-plane coupling, respectively.

  • 16.
    A. Sani, Negar
    Linköping University, Department of Science and Technology, Physics and Electronics.
    M-PSK and M-QAM Modulation/Demodulation of UWB Signal Using Six-Port Correlator2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays high speed and high data rate communication are highly demanded. Consequently, wideband and high frequency transmitter and receivers should be designed. New transmitters and receivers should also have low power consumption, simple design and low manufacturing price in order to fulfill manufacturers’ requests for mass production. Having all above specifications, six-port correlator is a proper choice to be used as modulator and demodulator in transmitters and receivers.

    In this thesis the six-port correlator is introduced, modeled and simulated using Advanced Design System (ADS) software. A simple six-port transmitter/receiver system with a line of sight link is modeled and analyzed in BER, path length and noise terms. The modulation in this system is QAM, frequency is 7.5 GHz and symbol rate is 500 Msymbol/s.

    Furthermore two methods are proposed for high frequency and high symbol rate M-PSK and M-QAM modulation using six-port correlator. The 7.5 GHz modulators are modeled and simulated in ADS. Data streams generated by pseudo random bit generator with 1 GHz bandwidth are applied to modulators. Common source field effect transistors (FETs) with zero bias are used as controllable impedance termination to apply baseband data to modulator. Both modulators show good performance in M-PSK and M-QAM modulation.

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    FULLTEXT01
  • 17.
    A. Taher, Ali
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    BIM Software Capability and Interoperability Analysis: An analytical approach toward structural usage of BIM software (S-BIM)2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study focused on the structuralanalysis of BIM models. Different commercial software (Autodesk products and Rhinoceros)are presented through modelling and analysis of different structures with varying complexity,section properties, geometry, and material. Beside the commercial software, differentarchitectural and different tools for structural analysis are evaluated (dynamo, grasshopper,add-on tool, direct link, indirect link via IFC).

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  • 18.
    A Österman, Sami
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Kumar, Shirish
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Vattenskärning: Teknologin och dess tillämpningsområden2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Water jet cutting is generally considered to be a versatile processing technique with a variety of applications. Pure water jet cutting makes it possible to cut through soft materials like rubber, while an added abrasive allows cutting of including steel and ceramics. The cut leaves neither any residual stress nor heat stress in the material. In addition, the surface finish is often of high enough quality, making post treatment unnecessary. The process does not yield in any dangerous gases and is relatively environmentally friendly. The purpose of this thesis was to investigate the water jet technology, its current, as well as new application areas. The goal was also to compare the technique with alternative processing methods in order to clarify the advantages and disadvantages between them. This was done in order to investigate which technologies are most appropriate to use depending on properties such as material, material thickness and size of the produced series. This paper has been written together from Sweden and France and a choice was hence made to investigate if the uses of water jet cutting differ between the two countries. To meet the objective, three questions were used to investigate how to expand the application areas of water jet cutting, what advantages and disadvantages there are between water jet cutting and other processing methods and how the scope of its applications differs between France and Sweden. The main sources of information for the work have been interviews with manufacturing companies that use water jet cutting, suppliers of water jet cutting machines and research institutes. Research articles have been used in order to extend the range of gathered information. Among primary sources for this report were websites of companies in the processing industry. This thesis shows that water jet technology is applicable in many industries and application areas that differ between France and Sweden, in France, used water jets are mainly used in the food industry, while it is more widespread in the engineering industry in Sweden. Companies in the Swedish market are skeptical about the use of water jet cutters exceeding 400 MPa, although it suggests many advantages. The main limitation of the water jet cutting procedure is the thickness of the material. Cutting steel beyond 30 mm in thickness, can result in a stream lag by delaying the water jet and thereby induce non‐precise cutting. This problem may be solved by changing the cutting parameters such as cutting speed or by inclining the cutting nozzle. Following an evaluation of plasma, laser and water jet cutters, none of the methods is directly competing with one another, since each single cutting technique is best suited for their intended use. The techniques complement each other rather than competing with one another.

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  • 19.
    Aaboen, Lise
    NTNU, Trondheim.
    BATON-CHANGING ON EGGSHELLS – TRANSFERRING SUPPLIER RELATIONSHIPS WHEN MOVING PRODUCTION2014Conference paper (Refereed)
    Abstract [en]

    Production transfers are a result of outsourcing and offshoring decisions. Though, because of

    the strategic focus of the outsourcing literature have not the operational issues of how

    relationship development between sender, receiver and raw material been fully depicted. The

    purpose of the present paper is to explore relationship development connected to transfer of

    raw material supplies responsibility during transfer of production. To fulfil the purpose, four

    different production transfers were studied: three from Sweden to China, Romania and

    Hungary respectively and one transfer from Holland to Sweden. We can see that the

    dependence and power shifts gradually between the sender and the receiver and the

    relationship between them sets the arena for what relationship is developed between the

    receiver and the raw material suppliers. Furthermore, short social distances can over bridge

    cultural and technological distances to some extent, because it motivates to take the

    relationship into a more developed state.

  • 20.
    Aaboen, Lise
    et al.
    Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
    Fredriksson, Anna
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    The relationship development aspect of production transfer2016In: Journal of Purchasing and Supply Management, ISSN 1478-4092, E-ISSN 1873-6505, Vol. 22, no 1, p. 53-65Article in journal (Refereed)
    Abstract [en]

    Production transfers are a result of outsourcing and offshoring decisions. Because of the strategic focus of the outsourcing literature, the operational issues of relationship development between sender and receiver and its impact on the transfer progress have not been fully depicted. The purpose of the present paper is to explore relationship development during production transfer. To fulfil this purpose, we studied three different production transfers and derived four propositions for further testing. Our main conclusions included that dependence and power gradually shift between the sender and the receiver and that the relationship between them sets the arena for what types of relationships can be developed between the receiver and the suppliers. Furthermore, short social distances can bridge cultural and technological distances to some extent, because it motivates the actors to bring their relationship into a more developed state. Finally, we noticed that the headquarters’ involvement can work both as an inhibitor as well as a converter.

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  • 21.
    Aaboen, Lise
    et al.
    Norwegian University of Science and Technology .
    La Rocca, Antonella
    BI Norwegian Business School.
    Lind, Frida
    Chalmers University of Technology.
    Perna, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management. Universita' Politecnica delle Marche.
    Shih, Tommy
    Starting up in Business Networks: Why relationships matter in entrepreneurship2016 (ed. 1st)Book (Refereed)
  • 22.
    Aagaard Fransson, Erik Johannes
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Wall-Horgen, Tobias
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Building and Evaluating a 3D Scanning System for Measurementsand Estimation of Antennas and Propagation Channels2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wireless communications rely, among other things, on theunderstanding of the properties of the radio propagationchannel, the antennas and their interplay. Adequate measurementsare required to verify theoretical models and togain knowledge of the channel behavior and antenna performance.As a result of this master thesis we built a 3D fieldscanner measurement system to predict multipath propagationand to measure antenna characteristics. The 3Dscanner allows measuring a signal at the point of interestalong a line, on a surface or within a volume in space. In orderto evaluate the system, we have performed narrowbandchannel sounding measurements of the spatial distributionof waves impinging at an imaginary spherical sector. Datawas used to estimate the Angle-of-Arrivals (AoA) and amplitudeof the waves. An estimation method is presented tosolve the resulting inverse problem by means of regularizationwith truncated singular value decomposition. The regularizedsolution was then further improved with the helpof a successive interference cancellation algorithm. Beforeapplying the method to measurement data, it was testedon synthetic data to evaluate its performance as a functionof the noise level and the number of impinging waves. Inorder to minimize estimation errors it was also required tofind the phase center of the horn antenna used in the channelmeasurements. The task was accomplished by directmeasurements and by the regularization method, both resultsbeing in good agreement.

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  • 23.
    Aagah, Orod
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Aryannejad, Siavash
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Dynamic analysis of soil-steel composite railway bridges: FE-modeling in Plaxis2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A soil-steel composite bridge is a structure comprised of corrugated steel plates, which are joined with bolted connections, enclosed in friction soil material on both sides and on the top. The surrounding friction soil material, or backfill, is applied in sequential steps, each step involving compaction of the soil, which is a necessity for the construction to accumulate the required bearing capacity. Soil-steel composite bridges are an attractive option as compared with other more customary bridge types, owing to the lower construction time and building cost involved. This is particularly true in cases where gaps in the form of minor watercourses, roads or railways must be bridged.

    The objective of this master thesis is the modelling of an existing soil-steel composite railway bridge in Märsta, Sweden with the finite element software Plaxis. A 3D model is created and calibrated for crown deflection against measurement data collected by the Division of Structural Engineering and Bridges of the Royal Institute of Technology (KTH) in Stockholm, Sweden.

    Once the 3D model is calibrated for deflection, two 2D models with different properties are created in much the same way. In model 1, the full axle load is used and the soil stiffness varied, and in model 2 the soil stiffness acquired in the 3D model is used and the external load varied. The results are compared to measurement data. In 2D model 1 an efficient width of 1,46 m for the soil stiffness is used in combination with the full axle load, and in 2D model 2 an efficient width of 2,85 m is used for the external load, in combination with the soil stiffness acquired in the 3D model.

    Aside from this, parametric studies are performed in order to analyse the effect of certain input parameters upon output results, and in order to analyse influence line lengths.

    Recreating the accelerations and stresses in the existing bridge using finite element models is complicated, and the results reflect this. Below are shown the discrepancies between model results and measurement data for the pipe crown. The scatter in the measurement data has not been taken into consideration for this; these specific numbers are valid only for one particular train passage.

    For crown deflection, the 3D model shows a discrepancy of 4%, 2D model 1 5% and 2D model 2 8% compared with measurement data. For crown acceleration, in the same order, the discrepancy with measurements is 1%, 71% and 21% for maximum acceleration, and 46%, 35% and 28% for minimum acceleration. For maximum crown tensile stress, the discrepancy is 95%, 263% and 13%. For maximum crown compressive stress, the discrepancy is 70%, 16% and 46%.

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  • 24.
    Aagah, Orod
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Kardan, Caesar
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Ett tillgängligt och användarvänligt boende: Anpassningsmöjligheter för människor med rörelsehinder och nedsatt rörelseförmåga2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this paper we have theoretically built a house designed for people with impaired mobility. The

    essay begins with an introduction in which the purpose of the work, the methodology and the

    depth-research part is presented. Then the layout that explains how we intend to adapt the house

    for the demands detailed in the depth-research part is presented. In the same chapter various

    structural components, such as different floors and walls, are specified.

    In the selection of materials we have taken into account the criteria of our specialization and

    adaptation to the aesthetic aspects, where we evaluate materials based upon our wishes regarding

    technique and form. There are also other aspects that are important in the selection of materials,

    including that these are adapted to technical traits of the construction elements and installations.

    In a later chapter the technical installations such as ventilation systems, heating systems,

    electricity and sanitation are presented, where both technical and financial aspects are described

    in detail. The economic aspects are also described in connection with calculating the building's

    power and energy requirements and then presented in the section where costs are accounted for.

    Finally, the work is summarized in the section “Conclusion and Discussion” in which we analyze

    all the work, and based on these analyses conclusions are drawn. During the course of work

    regulations such as Boverkets Byggregler (BBR) and other sources were used. These sources are

    presented in the bibliography section. We also received help and guidance from our supervisors

    in various parts of the work, which we are grateful for.

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  • 25.
    Aagerup, Ulf
    et al.
    Halmstad University, School of Business, Engineering and Science, Centre for Innovation, Entrepreneurship and Learning Research (CIEL).
    Frank, Anna-Sofia
    Halmstad University, School of Business, Engineering and Science.
    Hultqvist, Evelina
    Halmstad University, School of Business, Engineering and Science.
    The persuasive effects of emotional green packaging claims2019In: British Food Journal, ISSN 0007-070X, E-ISSN 1758-4108, Vol. 121, no 12, p. 3233-3246Article in journal (Refereed)
    Abstract [en]

    Purpose - The purpose of this paper is to investigate the effects of rational green packaging claims vs emotional green packaging claims on consumers' purchase propensity for organic coffee.

    Design/methodology/approach - Three within-subjects experiment were carried out (N=87, N=245, N=60). The experimental design encompasses packaging with rational green claims, emotional green claims, as well as a neutral (control) claim. Measured variables are introduced to assess participants' environmental commitment and information processing ability. A manipulated between-subjects variable is introduced to test how distraction interacts with preference for the claims.

    Findings - Overall, consumers prefer products with green claims over those with neutral (control) claims, and products with emotional green claims to those with rational green claims. The studies also reveal that this effect is moderated by participants' environmental commitment, information processing ability and by distraction. The findings were statistically significant (p<0.05).

    Research limitations/implications - As a lab experiment, the study provides limited generalizability and external validity. Practical implications - For most organic FMCG products, it is advisable to employ emotional packaging claims.

    Social implications - The presented findings provide marketers with tools to influence consumer behavior toward sustainable choices.

    Originality/value - The paper validates previous contributions on the effects of product claim types, and extends them by introducing comprehensive empirical data on all the Elaboration Likelihood Model's criteria for rational decision-making; motivation, opportunity and ability.

  • 26. Aagesen, Peter Tolstrup
    et al.
    Heyer, Clint
    Malmö högskola, Faculty of Culture and Society (KS), School of Arts and Communication (K3).
    Personality of Interaction: Expressing Brand Personalities Through Interaction Aesthetics2015In: 34th annual Chi Conference On Human Factors in Computing Systems, Chi 2016, ACM Digital Library, 2015, p. 3126-3130Conference paper (Refereed)
    Abstract [en]

    Practicing designers must usually relate to branding in some manner. A designed artifact must support the brand in a constructive way and help establish positive brand experiences, which in turn have strategic value for the brand's institution. While there is obvious application of visual branding knowledge to the visual form of interactive artifacts, interviews with expert practitioners reveal a lack of systematic means to craft an interaction aesthetic to support a brand. Our empirical study relates attributes of interactive experience to that of 'brand personality', a common way of quantifying how a brand should be perceived. We show that particular attributes of interactivity, such as whether an interaction has a continuous rather than discrete flow, are related to particular brand traits. Our empirical results establish a clear commercial significance for deeper, systematic ways of analyzing and critiquing interactive experiences.

  • 27.
    Aakash, förnamn
    et al.
    Department of Electronics and Communication Engg., Birla Institute of Technology.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Mohan, Rajendra
    Department of Physics, National Institute of Technology Patna.
    Mukherjee, Samrat
    Department of Physics, National Institute of Technology Patna.
    Structural, magnetic and hyperfine characterizations of nanocrystalline Zn-Cd doped nickel ferrites2017In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 441, p. 710-717Article in journal (Refereed)
    Abstract [en]

    In our present work, we have synthesized a series of Cd-Zn doped nickel ferrite ((Cd-0.5 Zn-x(x)) Ni0(.5)Fe(2)O(4); x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) through standard chemical co-precipitation method to study the influence of diamagnetic ions (Cd, Zn) on the magnetic properties of ferrites. XRD and Raman spectroscopy were employed for the structural characterizations. The refinement of the X-ray diffractogram data augmented by the Williamson-Hall plots showed the presence of Cd2+ vacancies and a strained crystal structure. The vibrational spectroscopy indicated the presence of lower space-group symmetry and a distorted crystal structure. Magnetic measurements showed the samples possessed low magnetic anisotropy along with a canted spin structure. The Mossbauer measurements confirmed the cation distribution and gave evidence of super transferred hyperfine interactions arising due to canted spin structure of the system.

  • 28.
    Aalberg, L
    et al.
    National Bureau of Investigation, Finland.
    Andersson, K
    Swedish National Laboratory of Forensic Science.
    Bertler, C
    Swedish National Laboratory of Forensic Science.
    Cole, MD
    University of Strathclyde, Glasgow.
    Finnon, Y
    University of Strathclyde, Glasgow.
    Huizer, H
    Netherlands Forensic Institute.
    Jalava, K
    National Bureau of Investigation, Finland.
    Kaa, E
    Aarhus Universitet.
    Lock, E
    Université de Lausanne.
    Lopes, A
    Laboratorio Policia Cientifica, Lisbon, Portugal.
    Poortman-van der Maar, A
    Netherlands Forensic Institute.
    Sippola, E
    National Bureau of Investigation, Finland.
    Dahlén, Johan
    Swedish National Laboratory of Forensic Science.
    Development of a harmonised method for the profiling of amphetamines: II. Stability of impurities in organic solvents2005In: Forensic Science International, ISSN 0379-0738, E-ISSN 1872-6283, Vol. 149, no 03-Feb, p. 231-241Article in journal (Refereed)
    Abstract [en]

    The present study focused on the stability of 22 amphetamine impurities dissolved in six organic solvents: isooctane, toluene, ethanol, dichloromethane, ethyl acetate, and diethyl ether. The aim was to find the most inert, and thereby most suitable, solvent for amphetamine profiling. Mixtures of the impurities were prepared in the different solvents, and changes in the concentrations of the individual compounds over-time were monitored by gas chromatographic analysis after 0, 4, 12, 24, 48, and 96 h. Isooctane and toluene provided the most inert conditions, although, a few of the impurities were insufficiently stable in these two solvents. The present experiments were performed as a part of the development of a harmonised method for profiling of amphetamine. The results can be used to support the choice of organic solvents for sample preparation. They also provide information about the stability of the impurities that are found in profiles of illicit amphetamine. This is essential due to the fact, that unstable compounds can have a negative influence on the comparison of profiles.

  • 29. Aalhuizen, Christoffer
    Potential of V2G in a Rural Low-Voltage Grid on Gotland for Voltage and Power Capacity Control2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish transportation sector needs to undergo major changes in order to achieve the established goals for climate and environment. The largest change is the replacement of fossil-fuelled vehicles to vehicles propelled by renewable energy sources, such as biofuels and electricity. To account for an increase in local electric power consumption, the electric power infrastructure of Sweden needs to adapt through expansion and reconstruction of the electric power grid. However, changes in infrastructure are usually expensive. It is therefore suitable to also examine alternative solutions, which could potentially be more cost efficient. One of these solutions are vehicle-to-grid (V2G), where electric vehicles acts as local electric power control and provides auxiliary services to the electric power grid. This thesis is a case study of a part of a low-voltage electric power grid on Gotland, with the goal of analysing the potential of V2G in the investigated area. The study focused on utilizing V2G for balancing electric power consumption and generation, and for adjusting voltage levels. Simulations of the area were executed in PSS®E for three different cases; one high-load case, low-load case and average-load case. It was found that by utilizing V2G a ramp up of electric power during mornings was delayed by approximately one hour, making the electric power grid potentially more compatible with photovoltaics (PV). However, the overall effects from V2G was fairly low. This outcome can partly be explained by the assumptions made in the report, and also due to some odd behaviour of the system model. 

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  • 30.
    Aalipour, Mojgan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Human Factors Approach for Maintenance Improvement2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The purpose of this research work is to explore and describe human factors affectingmaintenance execution. To achieve the purpose of this study, the influencing factors have been identified using a literature survey. They have been categorized into four main groups namely organizational, workplace, job and individual factors. The Analytical Hierarchy Process (AHP) method is employed on data questionnaires to rank the priority of the factors. The interrelationships between these factors have been recognized by theInterpretive Structural Modelling (ISM) model. In the present case studies, MICMAC1analysis technique is also implemented for identifying the driving, dependent, linkage and autonomous factors. The data was collected through a questionnaire survey involving the participation of 16 and 25 maintenance staff and 10 mining experts in Swedish and Iranian mines, respectively. Within the study, it has been identified that the temperature, work layout, tools design and tools availability are the most important factors in both mines related to these categories. However, the significant factors in the organizational and individual categories are different in the selected mines. The effect of workplace factors on the maintainability of mining equipment is discussed and thereafter a methodology for maintainability management in the design and operation phases is developed. In the thirdcase study HEART2 is applied to estimate the probability of human error occurring duringmaintenance execution in an Iranian cable company. This research supports maintenance management to gain knowledge of human factors that affect maintenance execution. Further, this understanding could be useful in the development of strategies to improve the execution of maintenance.Keywords: Human Factors, Maintenance Management, Human Reliability, HumanPerformance, AHP, ISM, MICMAC, HEART

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  • 31.
    Aalipour, Mojgan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ayele, Yonas Zewdu
    Department of Engineering and Safety, UiT The Arctic University of Norway, Tromsø.
    Barabadi, Abbas
    Tromsø University, Department of Engineering and Safety, UiT The Arctic University of Norway, Tromsø.
    Human reliability assessment (HRA) in maintenance of production process: a case study2016In: International Journal of Systems Assurance Engineering and Management, ISSN 0975-6809, E-ISSN 0976-4348, Vol. 7, no 2, p. 229-238Article in journal (Refereed)
    Abstract [en]

    Human reliability makes a considerable contribution to the maintenance performance, safety, and cost-efficiency of any production process. To improve human reliability, the causes of human errors should be identified and the probability of human errors should be quantified. Analysis of human error is very case-specific; the context of the field should be taken into account. The aim of this study is to identify the causes of human errors and improve human reliability in maintenance activities in the cable manufacturing industry. The central thrust of this paper is to employ the three most common HRA techniques—human error assessment and reduction technique, standardized plant analysis risk-human reliability, and Bayesian network—for estimating human error probabilities and then to check the consistency of the results obtained. The case study results demonstrated that the main causes of human error during maintenance activities are time pressure, lack of experience, and poor procedure. Moreover, the probabilities of human error, obtained by employing the three techniques, are similar and consistent

  • 32.
    Aalipour, Mojgan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Barabadi, Abbas
    Tromsø University, University of Tromsø - The Arctic University of Norway.
    Maintainability management of production facilities in complex and challenging operating conditions2015In: 2015 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM): Singapore, 6-9 Dec. 2015, Piscataway, NJ: IEEE Communications Society, 2015, p. 817-820, article id 7385761Conference paper (Refereed)
    Abstract [en]

    As equipment becomes more complex, repair process becomes more complicated, costly and time-consuming. Maintainability principles are developed to facilitate the repair process. Maintainability principles are applied in design phase and they are characteristic that affects time, accuracy, ease and safety requirements of the repair process. Considering Maintainability principles in the design phase are critical in challenging operational conditions such as Arctic offshore. To have an effective design for maintainability a systematic management approach is required during the design phase. This paper is developed a systematic guideline for maintainability management as an engineering discipline for challenges operational condition

  • 33.
    Aalipour, Mojgan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Barabadi, Abbas
    Tromsø University, University of Tromsø - The Arctic University of Norway.
    Work place factors effect on maintainability in challenging operating conditions2015In: 2015 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM): Singapore, 6-9 Dec. 2015, Piscataway, NJ: IEEE Communications Society, 2015, p. 767-771, article id 7385751Conference paper (Refereed)
    Abstract [en]

    Some industries such as mining industry create complex and challenging work place for maintenance crews. For example in an underground mine, for some machines, heavy maintenance tasks must be performed on site in a limited workspace in a harsh environment, including dust and improper illumination. Such operating conditions can increase the health, safety, and environment (HSE) risk, reduce the availability of the machines and increase the life cycle cost of equipment. A review of current mining equipment design and maintenance procedure confirms that considerable reduction in HSE risk, as well as substantial cost savings, can be achieved by considering human factors. This study discusses the effect of workplace factors on the maintainability of mining equipment. It presents the results from questionnaires on the effect of work place factors on maintainability performance given to maintenance staff at two mines, one in northern Sweden and the other in Iran.

  • 34.
    Aalipour, Mojgan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Singh, Sarbjeet
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Identification of Factors affecting Human performance in Mining Maintenance tasks2014In: Proceedings of the 3rd international workshop and congress on eMaintenance: June 17-18 Luleå, Sweden : eMaintenance, Trends in technologies & methodologies, challenges, possibilites and applications / [ed] Uday Kumar; Ramin Karim; Aditya Parida; Philip Tretten, Luleå: Luleå tekniska universitet, 2014, p. 71-76Conference paper (Refereed)
    Abstract [en]

    This paper investigates the factors affecting humanperformance in maintenance task in mining sector. Theobjective is identify various factors and to classify them asdriving (strong driving power and weak dependence) anddependent factors (weak driving power and strongdependence). The factors were identified through literaturesurvey and are ranked using mean score of data questionnaire.The reliability of measures is pretested by applyingCronbach’s alpha coefficient to responses to a questionnairegiven to maintenance personnel. The interrelationshipsbetween human factors have been recognized by interpretivestructural modeling (ISM). Further, these factors have beenclassified using matrice d'impacts croises-multiplicationappliqué à un classement (MICMAC) analysing. This casestudy will figure out the factors affecting human performancefor deriving maintenance management insights to improveproductivity in the mining sector. Further, this understandingmay be helpful in framing the policies and strategies formining industry. Temperature, lighting, documentation,communication and fitness are driving factors. Moreover,Work layout, tools availability, complex tasks, time pressure,safety, boss decisions, training, fatigue and motivation havestrong driving power as well as high dependencies and itcomes under the category of linkage factors.

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  • 35.
    Aaltio, Iiris
    et al.
    School of Economics and Business University of Jyväskylä, Finland.
    Kyrö, PaulaHelsinki School of Economics, Finland.Sundin, ElisabethLinköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Women, Entrepreneurship and Social Capital: A Dialogue and Construction2008Collection (editor) (Other academic)
    Abstract [en]

    This book explores social capital as the multiple relationships between gender, management and entrepreneurship. Human resources are the social capital of a firm and business life, based on trust as well as on expertise, values and cultural diversity. This calls for cross-cultural knowledge and an understanding of gender issues and individual differences in the social capital of the firm and society. The dialogue between women entrepreneurship and social capital theory and research has its special place among other women entrepreneurship books, the number of which has lately increased. It strengthens still in some respect the fragmented voice of women entrepreneurship research by providing a landscape of women entrepreneurs as creators of, and created by, social capital. It indicates how women entrepreneurs appear to have a special position in forming, developing and reorganizing the social capital in the business world. In its eleven chapters, twenty-six researchers representing a variety of disciplines from different parts of the world are presenting findings on diverse aspects of the dialogue between women entrepreneurship and social capital. As a consequence the central concepts, social capital, entrepreneurship and gender, are given a variety of meanings. Women entrepreneurs and business owners regardless of their cultural context, branch and education provide interesting ideas to the global debate on equality and social capital.

  • 36.
    Aalto, Jonatan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Neuman, Elisabeth
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Comparison of Punching Shear Design Provisions for Flat Slabs2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

    A new generation of EN 1992-1-1 (2004) also known as Eurocode 2 is under development

    and currently there is a set of proposed provisions regarding section 6.4

    about punching shear, PT1prEN 1992-1-1(2017). It was of interest to compare the

    proposal with the current punching shear design provisions.

    The aim of this master thesis was to compare the punching shear resistance obtained

    in accordance with both design codes. Furthermore the eect of some parameters

    on the resistance was to be compared. It was also of interest to evaluate the userfriendliness

    of the proposal.

    In order to meet the aim, a case study of a real  at slab with drop panels was performed

    together with a parametric study of a pure ctive  at slab. The parametric

    study was performed for inner, edge and corner columns in the cases prestressed,

    without and with shear reinforcement.

    It was concluded that the distance

    av from the column axis to the contra  exural

    location has a big in uence on the punching shear resistance. The factor

    ddg

    considering concrete type and aggregate properties also has a big impact on the resistance.

    The simplied estimation of

    av according to 6.4.3(2) in PT1prEN 1992-1-1

    (2017) may be inaccurate in some cases.

    The length

    b0 of the control perimeter has a larger eect on the resistance in EN

    1992-1-1 (2004) than in PT1prEN 1992-1-1 (2017).

    In PT1prEN 1992-1-1 (2017), studs located outside the second row has no impact

    on the resistance.

    The tensioning force in a prestressed  at slab has a larger in uence on the resistance

    in PT1prEN 1992-1-1 (2017) than in EN 1992-1-1 (2004). Furthermore,

    the reinforcement ratio is increased by the tendons, and thus aect the resistance in

    PT1prEN 1992-1-1 (2017).

    Clearer provisions for the denition of the support strip

    bs for corners and ends

    of walls are needed in PT1prEN 1992-1-1 (2017).

    It may be questionable if the reduction of the perimeter for a large supported area in

    accordance with 6.4.2(4) in PT1prEN 1992-1-1 (2017) underestimates the resistance

    v

    in some cases.

    Considering the work-load with PT1prEN 1992-1-1 (2017), more parameters are

    included. However, they may not require that much eort to obtain.

    Keywords: Punching shear, resistance, concrete,  at slab, design provisions, Eurocode

    2, case study, parametric study, shear reinforcement, prestressed

    vi

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  • 37.
    Aaman, Sophia
    et al.
    KTH, School of Industrial Engineering and Management (ITM).
    Hessel Lundberg, Johan Henrik
    KTH, School of Industrial Engineering and Management (ITM).
    Setting the seeds for a green growth -A Study of biofuel development in Indonesia’s transport sector2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Climate change poses as one of the major environmental issues on a global scale today, with one of the largest contributor to the climate change being the greenhouse gas (GHG) emissions. GHG emissions in turn is known to a large extent originate in anthropogenic energy use, especially fossil fuel usage. This leads to almost a quarter of the global emissions today being emitted from the transport sector as the sector is primary fueled by fossil fuels.

    Biofuels have been promoted as a strong candidate for fossil fuel substitution as it has similar properties while being renewable. However, even as biofuels have been increasing annually since 2008 globally, there are still concerns associated with the usages that have hindered its replacement of fossil fuels.

    Indonesia, one of the most populated countries in Southeast Asia, is projected to be one of the world’s leading economies in 2050. In 2030, Indonesia in projected to have doubled its energy consumption since 2014, indicating that the decisions and actions taken today in Indonesia will have a significant impact on the future fuel consumption. This, in combination with being the largest producer of palm oil in the world, gives it a great potential to be in a leading position in the future production of biofuels, especially biodiesel from palm oil. Additionally, Indonesia has set mandatory targets for biofuel share in the transport sector which indicates that the country also seeks to promote the usages of biofuels.

    This thesis intends to investigate Indonesia’s potential for biofuel development in the transport sector and which factors that could hinder it. More specifically, this study answers the two questions: (i) Which factors are hampering the development of biofuels in the Indonesian transportation sector from a multi-level perspective? and (ii) What is the projection of the Indonesian transport sector by 2030 in terms of fuel consumption and global warming potential (GWP) and what role could biofuels play in reducing those?

    The data used were collected by interviews with stakeholders in Indonesia and a literature study, which afterwards was processed with the tools Multi-Level Perspective (MLP) and Long-range Energy Alternatives Planning (LEAP). MLP is a concept aiming to describe how system transitions happens with the help of an examination of the linkages in between technology and society, whereas LEAP is an energy modeling tool used in order to create energy projections in different policy scenario options. In this research, MLP were used to capture and analyze the factors that influence the future implementation of biofuels in Indonesia from a socio-technical perspective, putting forward key barriers for biofuel implementation in Indonesia. LEAP was used to construct a model of the Indonesian transport sector to project the future fuel consumption and GWP emissions. This was used to examine biofuels importance as a fuel through scenarios where different Indonesian policy actions were appraised. Together, these two methods will provide an enlightening and concluding remark on the future possibilities for biofuels in Indonesia's transport sector in this thesis.

    The major finding of the first research question were that biofuels in Indonesia were being introduced in Indonesia as the government saw economic benefits and a solution to the increased energy demand in Indonesia and an increased energy security in going towards a domestic produced energy source. The need for biofuels were also increased due to an increased global sustainability awareness, which also reached Indonesia.

    Today, biofuels in Indonesia is in a socio-technical transition pathway to go from a niche innovation to a technology in the regime level, but in order for a breakthrough, a number of barriers needs to be addressed. The most mentioned barriers were the institutional and regulatory barriers, which mainly lays in a lack of cooperation amongst the regulatory institutions and a low rate of success of biofuel laws and regulations. Other barriers were the market barriers, closely connected in a subsidization of fossil fuels in Indonesia and a need for further subsidization of biofuels for the market for biofuels to exist in Indonesia. Furthermore, a technical barrier with the vehicle engine were seen as the engine needs improvements in order for a higher blending of biofuels in the fuel. There was also a concern of the perceived sustainability of biofuels in general (e.g. water scarcity and pollution) which was identified as a hindrance. It was also clear a social change is needed in order to push the biofuel breakthrough and enable it to reach its full potential. Today, the interviewees mainly see a development for the biofuel biodiesel and not for the biofuel bioethanol in Indonesia, which they mainly concluded as there is currently none or very little production and demand for bioethanol in Indonesia, and as well a lack of governmental support for bioethanol development.

    For the second research question four scenarios were used; Business as Usual (a continuation of current trends), Improved Standards (an investigation of higher emissions standards and an increasing fuel efficiency), Biofuel Mandate (a mandatory biofuel share in fuels) and the Low Carbon scenario (a combination of the previous two as well as introduction of electric vehicles, changed car preferences and higher biofuel blending targets). Cars represents a tenth of the vehicle fleet and the share of diesel car amongst the cars are 5% while gasoline stands for 95%, the rest of the vehicles are gasoline driven motorcycles. The main findings were: the total vehicle fleet will have doubled by 2030. This rapid increase could cause stress on the domestic fuel supply, as the yearly fuel consumption is expected to grow from 770 million GJ in 2014 to 1850 million GJ in 2030, an increase by 140%. In the projection the fossil fuels are blended with biofuels, diesel is mixed with biodiesel while gasoline is blended with bioethanol. The annual diesel fuel consumption is projected to increase from 350 million liters to 1100 million in the Business as Usual scenario where the current trend was expected to continue. The implementation of biodiesel and bioethanol in the Biofuel Mandate scenario. Additionally, the Biofuel Mandate scenario resulted in a 12.6% reduction of GHG emissions during the projected period. The cumulative GHG emissions in the projection is estimated to be 1630 million tonnes of carbon dioxide equivalents in 2030 for the Business as Usual scenario. In the transport sector, gasoline is projected to increase from 23 billion liters to 54 billion liters over the period. In the Improved Standards scenario, where the emission standards are increased from Euro2 to Euro6 in 2030 for cars and Euro4 for motorcycles in 2025 as well as an annual fuel economy improvement of 2%, the total fuel consumption is reduced with 20% and GWP by 18%. It was found that the annual GWP could be reduced by almost 31% below the 2014 level, at 47 million metric tonnes of CO2Eq, if the actions of the Low Carbon scenario were achieved.

    The barriers associated with the Improved Standards scenario were technical, institutional and regulatory while the Biofuel Mandate scenario also had financial, market and distribution barriers. The Low Carbon scenario had barriers from all of the identified barrier categories. The institutional and regulatory barrier was the most prevailing barrier for all of the scenarios.

    The recommended actions based on the content of this thesis is to firstly promote collaboration between governmental institutes, stakeholders and authorities and include all stakeholders in the decision progress, this way, frameworks and regulations will have a chance to improve and increase the knowledge about biofuels in all levels. It is also important to implement a stronger biofuel R&D culture, promote a more sustainable biofuel development and increase the public awareness of biofuels. The implementation of biofuels will have a reducing effect on the total GWP and fossil fuel consumption. Gasoline is projected to remain the predominant fuel in the transport sector. Therefore will actions targeting the reduction or substitution of gasoline be more impactful than those towards diesel. However due to the availability and current production capacity of biodiesel there is still potential for higher share of biodiesel in fuels.

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  • 38.
    Aamir Latif, Muhammad
    University of Borås, School of Engineering.
    Radar scattering from bodies of revolution using an efficient partial differential equation algorithm2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    A technique is presented for solving the problem of scattering by a three-dimensional body of revolution using a partial differential equation (PDE) technique, employed in conjunction with radiation boundary condition applied in the Fresnel region of the scatterer. The radiation boundary condition, which is used to truncate the PDE mesh, is based upon an asymptotic expansion derived by Wilcox. Numerical results illustrating the procedure and verifying the accuracy of the results are included. These results are compared with other theoretical calculations for perfectly conducting bodies of revolution of arbitrary shape.

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  • 39.
    Aamir, Syed Ahmed
    Linköping University. Linköping University, Department of Electrical Engineering.
    A 65nm, Low Voltage, Fully Differential, SC Programmable Gain Amplifier for Video AFE2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to rapid growth of home entertainment consumer market, video technology has been continuously pushed to deliver sharper pictures with higher resolution. This has brought about stringent requirements on the video analog front end, which often coupled with the low power and low voltage regulations had to deal with short channel effects of the deep submicron CMOS processes.

    This thesis presents the design of a fully differential programmable gain amplifier, as a subcircuit of a larger video digitizing IC designed at division of Electronic Systems. The switched capacitor architecture of the PGA does not only buffer the signal, but performs compensation for the sync-tip of analog video signal.

    The pseudo differential OTA eliminates tail current source and maintains high signal swing and has efficient common mode feedforward mechanism. When coupled with a similar stage provides inherent common moode feedback without using an additional SC-CMFB block.

    The PGA has been implemented using a 65 nm digital CMOS process. Expected difficulties in a 1.2 V OTA design make themselves evident in 65 nm, which is why cascaded OTA structures were inevitable for attaining gain specification of 60 dB. Nested Miller compensation with a pole shifting source follower, stabilizes the multipole system. The final circuit attains up to 200 MHz bandwidth and maintains high output swing of 0.85 V. High slew rate and good common mode and power supply rejection are observed. Noise requirements require careful design of input differential stage. Although output source follower stabilized the system, it reduces significant bandwidth and adds to second order non-linearity.

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  • 40.
    Aamir, Syed Ahmed
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Wikner, J Jacob
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A 1.2-V pseudo-differential OTA with common-mode feedforward in 65-nm CMOS2010In: Proceedings of the 17th IEEE International Conference on Electronics, Circuits, and Systems, Institute of Electrical and Electronics Engineers (IEEE), 2010, p. 29-32Conference paper (Refereed)
    Abstract [en]

    In this work, we describe the implementation of a 1. 2-V pseudo-differential operational transconductance amplifier (OTA) with common-mode feedforward (CMFF) and inher­ent common-mode feedback (CMFB) in a 65-nm, digital CMOS process. The OTA architecture provides an inher­ent CMFB when cascaded OTA structures are utilized andthis work has studied a cascaded amplifier consisting of fourstages. Due to the low-gain using core 65-nm circuit de­vices, the overall gain must be distributed on all four stages to acquire a gain of more than 60 dB, while maintaining a-3-dB bandwidth of 200 MHz. To achieve high gain, we propose using a modified, positive-feedback, cross-coupled input differential stage. The modified OTA achieves a high output swing of ± 0.85 V due to only two stacked transistors, 88 dB DC gain and a third-order harmonic of -60 dB for 800 mVpp at 30 MHz. Further on, in a capacitive buffer configuration, we achieve a high slew rate of 1240 V/µS, -3-dB bandwidth of 509 MHz, signal-to-noise ratio of 63 dB while consuming 10.4 mW power.

  • 41.
    Aamir, Syed Ahmed
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Wikner, J Jacob
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A 500-MHz low-voltage programmable gain amplifier for HD video in 65-nm CMOS2010In: Proceedings of 28th IEEE Norchip Conference., NORCHIP'10, Tampere: www.ieee.org , 2010, p. 1-4Conference paper (Refereed)
    Abstract [en]

    This work describes the implementation of a 1.2-V programmable gain amplifier (PGA) for high-definition (HD) video digitizers in a 65-nm digital CMOS process. The “pseudo” switched-capacitor (SC) PGA architecture buffers the video signal, without switching, during the active video. The SC circuitry is used for setup of DC operating point during horizontal and vertical blanking periods. Additionally, it compensates for the `sync-tip' of analog video signals to an equal blanking level for increased dynamic range to the digitizer following the PGA. The operational transconductance amplifier (OTA) employed as main amplifier in the PGA is a pseudo-differential, positive-feedback input stage architecture with a common-mode feedforward (CMFF) technique. The common-mode feedback (CMFB) is provided once two OTAs are cascaded. Schematic-level simulation results show that the OTA maintains a -3-dB bandwidth of 550 MHz, while keeping the distortion HD3 at -60 dB for a 30-MHz, 850 mVpp high definition video signal. The 88 dB DC gain is distributed among four OTA stages and the overall, combined PGA achieves a signal-to-noise ratio of 63 dB. Due to only two stacked transistors, it achieves high output swing of ±0.85 V, 1240 V/μs slew rate while consuming 10.4 mW power.

  • 42.
    Aandahl, Hanna
    Blekinge Institute of Technology, School of Planning and Media Design.
    Tryggare Park: Åtgärdsförslag för Kroksbäcksparken ur ett trygghetsperspektiv2011Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [sv]

    Kan trygghet skapas? Trygghetsfrågorna har fått ett allt större utrymme i debatten om staden. Forskningen och debatten är långt ifrån entydig och recepten på trygghet varierar kraftigt mellan olika länder. Grovt kan de förespråkade åtgärderna delas in i två läger: säkerhet och trygghet. ”Säkerhet” med framför allt situationell brottsprevention med den filosofin att skadegörelse, våld och stölder leder till otrygghet, vilket i sin tur leder till att människor inte vågar ta plats i det offentliga rummet. Konsekvensen blir att de offentliga platserna mister sin sociala kontroll, och kriminalitet och otryggheten får ytterligare spelrum. ”Trygghet” förespråkar istället skapandet av en levande stad där folk vågar ta plats och på så sätt utöva en social och informell övervakning. I detta arbete undersöker jag hur tryggheten fungerar och hur den kan ökas i en otrygg park i södra Malmö -Kroksbäcksparken,

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  • 43.
    Aarao, J
    et al.
    University of South Australia.
    Bradshaw-Hajek, B H
    University of South Australia.
    Miklavcic, Stan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ward, D A
    University of South Australia.
    Numerical implementation of the EDEM for modified Helmholtz BVPs on annular domains2011In: JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS, ISSN 0377-0427, Vol. 235, no 5, p. 1342-1353Article in journal (Refereed)
    Abstract [en]

    In a recent paper by the current authors a new methodology called the Extended-Domain-Eigenfunction-Method (EDEM) was proposed for solving elliptic boundary value problems on annular-like domains. In this paper we present and investigate one possible numerical algorithm to implement the EDEM. This algorithm is used to solve modified Helmholtz BVPs on annular-like domains. Two examples of annular-like domains are studied. The results and performance are compared with those of the well-known boundary element method (BEM). The high accuracy of the EDEM solutions and the superior efficiency of the EDEM over the BEM, make EDEM an excellent alternate candidate to use in the animation industry, where speed is a predominant requirement, and by the scientific community where accuracy is the paramount objective.

  • 44.
    Aarao, J
    et al.
    University of South Australia.
    Bradshaw-Hajek, B H
    University of South Australia.
    Miklavcic, Stan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ward, D A
    University of South Australia.
    The extended-domain-eigenfunction method for solving elliptic boundary value problems with annular domains2010In: JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, ISSN 1751-8113, Vol. 43, no 18, p. 185202-Article in journal (Refereed)
    Abstract [en]

    Standard analytical solutions to elliptic boundary value problems on asymmetric domains are rarely, if ever, obtainable. In this paper, we propose a solution technique wherein we embed the original domain into one with simple boundaries where the classical eigenfunction solution approach can be used. The solution in the larger domain, when restricted to the original domain, is then the solution of the original boundary value problem. We call this the extended-domain-eigenfunction method. To illustrate the methods strength and scope, we apply it to Laplaces equation on an annular-like domain.

  • 45.
    Aardal, Karen
    et al.
    Department of Mathematics, Linköping Institute of Technology.
    Ari, Aysen
    Luleå tekniska universitet.
    Decomposition principles applied to the dynamic production and work-force scheduling problem1987In: Engineering Costs and Production Economics, ISSN 0167-188X, E-ISSN 1878-4011, Vol. 12, no 1-4, p. 39-49Article in journal (Refereed)
    Abstract [en]

    One of the most important problems in the production and inventory planning field, is the scheduling of production and work force in a dynamic environment. Although this problem can be formulated as a linear program, it is often quite difficult to solve directly, due to its large scale. Instead, it might be fruitful to use a decomposition approach. Decomposition, in general, means decomposing a difficult problem into several easier, or a sequence of easier problems which are later coordinated to reconstruct the original problem.In this report we discuss several possibilities of applying the most common decomposition principles, namely Benders (primal) and Datnzig-Wolfe (dual), as well as a relatively new decomposition method, called cross decomposition, to the dynamic, multiproduct production and employment planning problem. A number of special cases are also presented.

  • 46.
    Aardal, Karen
    et al.
    CORE, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
    Ari, Aysen
    Luleå tekniska universitet.
    On the resemblance between the Kornai-Liptak and cross decomposition techniques for block-angular linear programs1990In: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 46, no 3, p. 393-398Article in journal (Refereed)
    Abstract [en]

    In this paper the resemblance is demonstrated between the master- and subproblems generated by the Kornai-Liptak algorithm and the subproblems obtained by using the cross decomposition method on linear optimization problems with block-angular structure. The significance of the similarity between these two algorithms becomes apparent considering the main disadvantage attributed to cross decomposition. In cross decomposition a master problem has to be solved from time to time since the subproblems alone do not always give a converging sequence of primal and dual solutions. But if the cross decomposition algorithm is modified in such a way that the successive primal and dual subproblem solutions are taken into consideration with equal weights, this results in the Kornai-Liptak algorithm for which convergence is guaranteed

  • 47.
    Aare, Kätlin
    et al.
    Stockholm University, Faculty of Humanities, Department of Linguistics, Phonetics.
    Włodarczak, Marcin
    Stockholm University, Faculty of Humanities, Department of Linguistics, Phonetics.
    Heldner, Mattias
    Stockholm University, Faculty of Humanities, Department of Linguistics, Phonetics.
    Backchannels and breathing2014In: Proceedings from FONETIK 2014: Stockholm, June 9-11, 2014 / [ed] Mattias Heldner, Stockholm: Department of Linguistics, Stockholm University , 2014, p. 47-52Conference paper (Other academic)
    Abstract [en]

    The present study investigated the timing of backchannel onsets within speaker’s own and dialogue partner’s breathing cycle in two spontaneous conversations in Estonian. Results indicate that backchannels are mainly produced near the beginning, but also in the second half of the speaker’s exhalation phase. A similar tendency was observed in short non-backchannel utterances, indicating that timing of backchannels might be determined by their duration rather than their pragmatic function. By contrast, longer non-backchannel utterances were initiated almost exclusively right at the beginning of the exhalation. As expected, backchannels in the conversation partner’s breathing cycle occurred predominantly towards the end of the exhalation or at the beginning of the inhalation. 

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    Backchannels and breathing
  • 48.
    Aare, Magnus
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Evaluation of head response to ballistic helmet impacts, using FEM2003Conference paper (Refereed)
  • 49.
    Aare, Magnus
    et al.
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Kleiven, Svein
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Halldin, Peter
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Injury tolerances for oblique impact helmet testing2004In: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 9, no 1, p. 15-23Article in journal (Refereed)
    Abstract [en]

    The most frequently sustained severe injuries in motorcycle crashes are injuries to the head, and many of these are caused by rotational force. Rotational force is most commonly the result of oblique impacts to the head. Good testing methods for evaluating the effects of such impacts are currently lacking. There is also a need for improving our understanding of the effects of oblique impacts on the human head. Helmet standards currently in use today do not measure rotational effects in test dummy heads. However rotational force to the head results in large shear strains arising in the brain, which has been proposed as a cause of traumatic brain injuries like diffuse axonal injuries (DAI). This paper investigates a number of well-defined impacts, simulated using a detailed finite element (FE) model of the human head, an FE model of the Hybrid III dummy head and an FE model of a helmet. The same simulations were performed on both the FE human head model and the FE Hybrid III head model, both fitted with helmets. Simulations on both these heads were performed to describe the relationship between load levels in the FE Hybrid III head model and strains in the brain tissue in the FE human head model. In this study, the change in rotational velocity and the head injury criterion (HIC) value were chosen as appropriate measurements. It was concluded that both rotational and translational effects are important when predicting the strain levels in the human brain.

  • 50.
    Aare, Magnus
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Halldin, Peter
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Proposed global injury thresholds for oblique helmet impacts2003Conference paper (Refereed)
1234567 1 - 50 of 199304
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