Digital video transmission is widely used nowadays in multimedia. Frame dropping, freeze and reduced number of frames in the transmitted video are common symptoms of bad transmission quality. In order to assess the quality of transmission, a criterion is introduced in a model for a no reference video jerkiness measure [3]. This model is dierent from the former models presented as it depends on viewing conditions and video resolutions, so it is applicable for any frame size from QCIF to HD. The model uses simple mathematical equations of jerkiness and can be used for any video sequence [3]. A model of reduced reference method (Qtransmission) which depends on a pre-measured Jerkiness is introduced as a suggestion of future work.
Transporting solid particles in oil and gas flow cause erosion damage to the pipeline and fittings. The aim of this thesis is to study the effect of impact velocity on the erosion damage in 90 degree long elbow by using two different erosion models namely, Oka model and E/CRC model. Those correlation applied at air-borne sand eroding, methane-borne sand eroding, mixed gas-borne sand eroding, and multiphase (gas- oil) borne sand eroding Inconel 625. The commercial computational fluid dynamics (CFD) code STAR-CCM+ is used to obtain the average and maximum erosion rate by using the above mentioned models and compared them with the previous results.
Abstract: The complexity of environmental, social, economical, and technological objectives creates a challenge for decision makers when prioritizing the right measures that will move a project or organization toward sustainability at least cost. Currently there are methods or tools available to assist in this decision making and through a strategic approach potentially enhance the process. The focus of this thesis is to evaluate how the quantitative nature of economic detail as a tool which has been informed by a strategic sustainable framework can contribute to the complex decision making process for sustainable development when prioritizing measures. A two- step matrix format is used to represent the proposed approach. The complexity of sustainable development issues for decision makers within Sweden’s energy sector provides a suitable case study to explain this approach. Karlskrona, Sweden district heat was chosen. The results revealed an enhanced decision making process utilizing the proposed approach in district heat thus ensuring organizational and social profitability as defined by, static and dynamic efficiency and equitable allocation. The thesis concludes that the suggested approach has the potential to enhance the decision making process for strategic sustainable development when prioritizing measures in district heat and may be universal in its application in many other sectors. However, further validation of the approach through testing in real life situations is recommended.
This thesis examines community energy planning in Sweden and Canada with the aim of revealing strategies that move communities towards energy sustainability. Unsustainable energy activities are identified as major threats on both local and global levels. The challenges for energy systems are discussed and a possible scenario of a future community with sustainable energy production and consumption is presented. The literature review examines community energy planning guidebooks and key theoretical and methodological concepts including ingenuity, soft energy paths and backcasting from socio-ecological principles of sustainability. Following an analysis of energy supply and demand in a broad systems context, and a review of policies and programs supporting or hindering community energy planning, energy plans from eleven Swedish and eleven Canadian communities are evaluated. Characteristics of progressive energy planning as uncovered in the literature review form a framework for evaluating the visions, strategies and actions described in the plans. Sweden is recognized as an early player in community energy planning. Although Swedish energy plans do not contain all of the identified progressive strategies, national leadership and funding have played a role in Sweden’s successes. More recent Canadian plans are found to be highly progressive, suggesting that Canadian communities who follow their plans can too be successful in transforming their energy systems towards sustainability.
Since the dawn of humanity design has influenced human life. Today, facing the depletion of the socio-ecological system, increasing complex problems threaten humanity’s existence. Design has been a contributor to creating such problems, yet with appropriate tools can become a source for solutions. Design Thinking (DT) was identified as a possible approach that could contribute to Strategic Sustainable Development (SSD). The purpose of this thesis is to examine potential contributors and hindrances of the DT process with regards to SSD, and create a prototype for an integrated process that could help achieve more strategic and sustainable outcomes. With the use of the Framework for Strategic Sustainable Development (FSSD) as a lens to examine the above, along with interviews, Action Research and expert feedback, an integrated process was created. Results of the interviews and FSSD analysis helped shape two prototypes that were examined through the mentioned methods. It was indicated by participants of the Action Research and by experts that the prototype could help reach a strategic and sustainable outcome, and further refinement should be pursued. The final prototype is presented as part of the discussion, suggesting additional tools and actions that if included could create a possible Sustainable DT (SDT) process.
Engineering education in Sweden as in the rest of the world is experiencing a decline in student interest. There are concerns about the ways in which students think about engineering education, why they join an academic programme in engineering, and why they persist in their studies. In this context the aims of the Nationellt ämnesdidaktiskt Centrum för Teknikutbildning i Studenternas Sammanhang project (CeTUSS) is to investigate the student experience and to identify and support a continuing network of interested researchers, as well as in building capacity for disciplinary pedagogic investigation. The Stepping Stones project brings together these interests in a multi-researcher, multi-institutional study that investigates how students and academic staff perceive engineering in Sweden and in Swedish education. The first results of that project are reported here. As this study is situated uniquely in Swedish education, it allows for exploration of a Swedish perspective on conceptions of engineering. The Stepping Stones project was based on a model of research capacity-building previously instantiated in the USA and Australia (Fincher & Tenenberg, 2006).
In modern telecommunication systems like hands-free and teleconferencing systems, the problem arise during conversation is the creation of an acoustic echo. This problem degrades the quality of the information signal. All speech processing equipments like noise cancelling headphones and hearing aids should be able to filter different kinds of interfering signals and produce a clear sound to the listener. Currently, echo cancellation is a most interesting and challenging task in any communication system. Echo is the delayed and degraded version of original signal which travels back to its source after several reflections. Eliminating this effect without affecting the original quality of the speech is a challenge of research in present days. Echo cancellation in voice communication is a process of removing the echo to improve the clarity and quality of the voice signals. In our thesis we mainly focused on the acoustic echo cancellation in a closed room using adaptive filters. The Acoustic echo cancellation with adaptive filtering technique will more accurately enhance the speech quality in hands free communication systems. The main aim of using adaptive algorithms for echo cancellation is to achieve higher ERLE at higher rate of convergence with low complexity. The adaptive algorithms NLMS, APA and RLS are implemented using MATLAB. These algorithms are tested with the simulation of echo occurring environment by using constant room dimensions , microphone and source positions. The performance of the NLMS, APA and RLS are evaluated in terms ERLE and misalignment. The results show that RLS algorithm achieve good performance with more computational complexity comparing with the NLMS and APA algorithms. The NLMS algorithm has very low computational complexity comparing to RLS and APA algorithms. The results are taken for both input signal as speech signal and noise separately and plotted in the results section.
The aim of this work is to investigate analytical and experimental vibration of composite beam. The composite beam is used as composite footbridge model prototype which is assumed. For the dynamic test, hammer excitation is used to excite the beam at fixed locations. The modal parameters are extracted from the time response using a time domain analysis, i.e. the stochastic subspace identification technique. Finite element models for different boundary conditions are constructed using the commercial finite element software package ANSYS for natural frequencies of the beam to support and verify the dynamic measurements. The result obtained from analytical solution, dynamic tests and the FEM are presented and analysed.
Human society faces serious environmental and social threats as a result of systemic unsustainable actions and values. This is a time of cultural self-evaluation and profound change. This study examines how 13 social and environmental change-based organizations, through network partnerships and a robust organizational knowledge-base, are responding to these challenges. A systems perspective was used as a guide to promote a holistic understanding of the actors within the system, their perceptions of success, strategies, actions and tools used to guide them toward sustainability. The results indicate that organizations seeking to scale-up their impact toward sustainability might benefit from the following success factors: 1. Collaboration with diverse partners to contribute to more effective interventions in complex systems, 2. Integrating comprehensive definitions of sustainability with organizational vision to facilitate success, 3. The application of leverage points and transparent prioritization processes to asure congruence between organizational purpose and actions, 4. Practices of dialogue and deep listening build rewarding partnerships and, 5. Metrics that support partnerships and gauge progress toward sustainability. In conclusion network partnerships have the potential to generate widespread sustained change and can be supported by complex systems science and a Framework for Strategic Sustainable Development.
A stochastic process or sometimes called random process is the counterpart to a deterministic process in theory. A stochastic process is a random field, whose domain is a region of space, in other words, a random function whose arguments are drawn from a range of continuously changing values. In this case, Instead of dealing only with one possible 'reality' of how the process might evolve under time (as is the case, for example, for solutions of an ordinary differential equation), in a stochastic or random process there is some indeterminacy in its future evolution described by probability distributions. This means that even if the initial condition (or starting point) is known, there are many possibilities the process might go to, but some paths are more probable and others less. However, in discrete time, a stochastic process amounts to a sequence of random variables known as a time series. Over the past decades, the problems of synergetic are concerned with the study of macroscopic quantitative changes of systems belonging to various disciplines such as natural science, physical science and electrical engineering. When such transition from one state to another take place, fluctuations i.e. (random process) may play an important role. Fluctuations in its sense are very common in a large number of fields and nearly every system is subjected to complicated external or internal influences that are often termed noise or fluctuations. Fokker-Planck equation has turned out to provide a powerful tool with which the effects of fluctuation or noise close to transition points can be adequately be treated. For this reason, in this thesis work analytical and numerical methods of solving Fokker-Planck equation, its derivation and some of its applications will be carefully treated. Emphasis will be on both for one variable and N- dimensional cases.
The main aim of this thesis work is to find/implement various methods that convert Conventional Stereoscopic 3D Video (CSV) to Multiview video (MVV). The work investigates different methods that can produce multiple views given a stereoscopic pair from a frame of a particular video sequence and continues with the process of selecting the best among investigated methods that has optimum quality and speed. In contrast to the existing algorithms, this work disregards the physical depth but instead focus on pixel value correspondence. The intermediate view generation in this work is not considered as a geometrical problem, but a morphing problem. Different morphing algorithms (mesh, field and thin plate spline morphing techniques) are considered for conversion. Performance of each morphing algorithm is in turn compared using different correspondence matching techniqes. The investigated methods aim to produce arbitrary number of novel synthesized camera views from a sparse view set. Mesh morphing algorithm is found to be a better candidate in terms of signal to noise ratio, but requires accurate correspondences at edges of an object in a particular scene and also needs more execution time to generate more number of views. A new approach to field morphing has been introduced in this thesis work, which performs better in terms of execution time and also found to produce intermediate views with reasonable signal to noise ratio. This approach is observed to bring good trade off between speed and accuracy. This conversion has an advantage it can be used as a decompression mechanism that can produce multiple views required for an Autostereoscopic 3D display from a stereoscopic left and right pair. This approach also brings the benefit of backward compatibility as present standards for CSV may be used to provide multiview 3D video to high fidelity Autostereoscopic 3D displays of the future. This work has applications in free view point television, video conferencing systems etc.,
Innehållet i denna rapport är ett resultat av ett moment i utbildningen till Utvecklingsingenjör i Maskinteknik. Arbetet har skett genom ett samarbete mellan Linus Adolfsen, Kockums AB och Blekinge Tekniska Högskola. Rapporten behandlar i stort två moment, ett praktiskt och ett teoretiskt. Den första delen, den praktiska, gick ut på att finna en metod för att överbrygga steget från modell till verklighet på ett effektivt sätt. Detta resulterade i en egenutvecklad programvara som kan läsa in utdatafilen från Tribon (CAD programvara) och översätta detta till en programfil för Herber CNC 90 bockningsmaskin. Den andra delen är teoretisk och är en analys av verksamheten utifrån perspektivet att medge förtillverkning. Resultatet blev en analys av den berörda verksamheten med förslag på hur man ska åtgärda de problem och hinder som finns idag. Det gav även stort upphov till förslag på vidare studier.
Recently, cooperative communication has gained significant interest due to the fact that it exploits spatial diversity and provides capacity/performance gain over conventional single- input single-output (SISO) systems. A mobile node with single antenna can cooperate with a nearby mobile node having single antenna in multi-user environment to create the effect of virtual multiple antenna system. Hence, reducing the complexity associated with actual multiple antenna systems. Despite the small size and power constraints, a mobile node can still benefit from spatial diversity by employing cooperation, thus saving transmission power and increasing the coverage range of the network. In this thesis, we have selected some of relaying protocols, namely, amplify-and-forward, decode-and-forward, detect-and-forward, and selective detect-and-forward that are studied and implemented for two different relaying geometries, i.e. equidistant and collinear. Results are studied and compared with each other to show the performance of each protocol in terms of average symbol error probabilities. The considered system model has three nodes, i.e. source, relay, destination. Communicating nodes are considered to be half-duplex with single antenna for transmission and reception. The source, when communicating with the destination, broadcasts the information, which is heard by the nearby relay. The relay then uses one of the cooperation protocols. Finally, the relayed signal reaches the destination, where it is detected by maximal ratio combiner (MRC) and combined with the direct transmission for possible diversity gains. The transmission path or the channel is modeled as a frequency non-selective Rayleigh fading in the presence additive white Gaussian noise (AWGN). The effect of path loss has been observed on cooperation for collinear arrangement with exponential decay up to four. Considering equidistant arrangement, decode-and-forward shows good performance at high signal-to-noise ratio (SNR) while amplify-and-forward is very promising for very low SNR. A selective relaying scheme called selective detect-and- forward is also presented which outperforms its fixed counterparts for a wide range of SNR.
Identification of modal parameters from output-only data is studied in this work. The proposed methodology uses transmissibility functions obtained under different loading conditions to identify resonances and mode shapes. The technique is demonstrated with numerical simulations on a 2-DOF system and a cantilever beam. To underpin the simulations, a real test was done on a beam to show the efficiency of the method. A practical application of the method can be to identify structures subjected to moving loads. This is demonstrated by using FEM-model of a cantilever beam with a moving load.
This thesis contains the product development work towards a, for Alfa Laval Lund AB, alternative product to eradicate Legionella bacteria from domestic hot water systems. The existing product at Alfa Laval Lund AB, the AquaProtect, is having problems to reach costumers with small and medium size systems. The product developed in this thesis should be in a much more attractive price range for small and medium size systems. It should also work in any domestic heating system with circulation. Making it possible for, for example, the vulnerable people at elderly care housings to have Legionella bacteria free water.
It is not always obvious how to compare a given test specification with measured field data. This article presents a systematic method based on the shock response spectrum and the fatigue damage spectrum. A random-on-random test specification for tracked vehicles, AECTP 400, is used as an example.
Accurate road profiles are useful in vehicle design, such as for simulation of durability and ride quality. Laser/inertial profilometers typically record I mm wide profiles. The question is how well such a profile matches perceived vehicle wheel roughness. The objective here was to create a more representative wheel track longitudinal profile. Simulated and measured wheel vibration was compared on a 6km long road. Simulations were made for several definitions of the profile. Results for single laser sensor profiles showed reasonable likeness to truck perceived roughness. By far the best likeness (14.5% better) was achieved when the profile was based on triangular 25%-50%-25% weighted data from three sensors in the wheel track. Clearly, vehicle engineers can benefit from using multiple laser profile sensors, instead of a single sensor. This will improve test accuracy, thus reducing vehicle design project lead times and costs.
Nättraby Verktygs AB i Ronneby konstruerar och producerar balpressar vars funktion är att pressa samman kartong, plast eller liknande material till kompakta balar. Dessa balar medför underlättad hantering av material som kan återvinnas för företag. Balpressarna används främst inom verksamhetsområden med stor åtgång av återvinningsbart material, exempelvis livsmedelsaffärer. Problemställningen vid detta examensarbete är att i en äldre version av en balpress har sprickbildning på pressplattan upptäckts efter en viss tids användning. Huvuduppgiften för detta examensarbete har därför varit att utföra hållfasthetsanalyser på pressplattorna för tre olika balpressar i deras sortiment. Denna rapport beskriver momenten samt arbetsgången för att genomföra dessa analyser och beskriver utförligt metoderna som använts. Hållfasthetsanalyserna är uppdelade i två delar, en statisk FEM-analys och en utmattningsanalys av konstruktionen. I den första delen av rapporten genomförs en FEM-analys på den gamla varianten av pressplattan för att se om analysen påvisar samma kritiska områden som företaget upptäckt. Resultatet visade att spänningen var högre i dessa områden än i övriga konstruktionen men under sträckgränsen för materialet. Därför beskriver nästa del av rapporten utförandet av en utmattningsanalys av pressplattan. Denna analys består av en svetsanalys för de svetsförband som finns i de kritiska områdena. Som metod vid svetsanalysen har “hot spot-metoden” använts vilken ger en uppskattning av hur många lastcykler dessa svetsförband kan belastas innan sprickbildning sker. Därefter har samma analyser genomförts på den nuvarande pressplattan och en pressplatta för en kommande modell. I sista delen av rapporten tas ett koncept av en möjlig framtida pressplatta fram där fokus ligger på minskad vikt, minskat antalet detaljer samt ökad hållfasthet. Det framtagna konceptet analyseras på samma sätt som de tidigare tre pressplattorna för att verifiera om detta koncept har ökad hållfasthet och livslängd.
The use of internet has increased over the past years. Many users may not have good intentions. Some people use the internet to gain access to the unauthorized information. Although absolute security of information is not possible for any network connected to the Internet however, firewalls make an important contribution to the network security. A firewall is a barrier placed between the network and the outside world to prevent the unwanted and potentially damaging intrusion of the network. This thesis compares the performance of Linux packet filtering firewalls, i.e. iptables and shorewall. The firewall performance testing helps in selecting the right firewall as needed. In addition, it highlights the strength and weakness of each firewall. Both firewalls were tested by using the identical parameters. During the experiments, recommended benchmarking methodology for firewall performance testing is taken into account as described in RFC 3511. The comparison process includes experiments which are performed by using different tools. To validate the effectiveness of firewalls, several performance metrics such as throughput, latency, connection establishment and teardown rate, HTTP transfer rate and system resource consumption are used. The experimental results indicate that the performance of Iptables firewall decreases as compared to shorewall in all the aspects taken into account. All the selected metrics show that large numbers of filtering rules have a negative impact on the performance of both firewalls. However, UDP throughput is not affected by the number of filtering rules. The experimental results also indicate that traffic sent with different packet sizes do not affect the performance of firewalls.
Wireless Mesh Networks (WMNs) are bringing revolutionary change in the field of wireless networking. It is a trustworthy technology in applications like broadband home networking, network management and latest transportation systems. WMNs consist of mesh routers, mesh clients and gateways. It is a special kind of wireless Ad-hoc networks. One of the issues in WMNs is resource management which includes routing and for routing there are particular routing protocols that gives better performance when checked with certain parameters. Parameters in WMNs include delay, throughput, network load etc. There are two types of routing protocols i.e. reactive protocols and proactive protocols. Three routing protocols AODV, DSR and OLSR have been tested in WMNs under certain parameters which are delay, throughput and network load. The testing of these protocols will be performed in the Optimized Network Evaluation Tool (OPNET) Modeler 14.5. The obtained results from OPNET will be displayed in this thesis in the form of graphs. This thesis will help in validating which routing protocol will give the best performance under the assumed conditions. Moreover this thesis report will help in doing more research in future in this area and help in generating new ideas in this research area that will enhance and bring new features in WMNs.
Designing antenna arrays based on travelling wave structures has been studied extensively during the past couple of decades and literature on several array topologies is present. It has been an active area of research as constant improvement of antenna arrays is desired for different communication systems developed. Slotted waveguide antennas are one form of travelling wave structures which is adapted in this study due to several advantages offered over other planar array structures. Waveguide slots have been used for a couple of decades as radiating elements. Several design studies have been carried out regarding use of slots with different orientations and geometry and cascading them together to be used as array antennas. Waveguide antennas are preferred as they provide low losses in the feed structure and also offer good radiation characteristics. This study provides a design procedure for implementing a circular polarized planar antenna array based on slotted waveguide structures. The antenna is designed to work in the 19.7 - 20.2 GHz range which is the operating frequency for the downlink of satellites.
The User Equipments (UE) nowadays are able to provide various internet applications and services that raise the demand for high speed data transfer and Quality of Service (QoS). Accordingly, next generation mobile communication systems driven by these demands are expected to provide higher data rates and better link quality compared to the existing systems. Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SC-FDMA) are strong multiple access candidates for the uplink of the International Mobile Telecommunications-Advanced (IMT-Advanced). These multiple access techniques in combination with other promising technologies such as multi-hops transmission and Multiple-Input-Multiple-Output (MIMO) will be utilized to reach the targeted IMT-Advanced system performance. In this thesis, OFDMA and SC-FDMA are adopted and studied in the uplink of Long Term Evolution (LTE). Two transmission scenarios are considered, namely the single hop transmission and the relay assisted transmission (two hops). In addition, a hybrid multiple access technique that combines the advantages of OFDMA and SC-FDMA in term of low Peak-to-Average Power Ratio (PAPR) and better link performance (in terms of Symbol Error Rate (SER)) has been proposed in relay assisted transmission scenario. Simulation results show that the proposed hybrid technique achieves better end-to-end link performance in comparison to the pure SC-FDMA technique and maintains the same PAPR value in access link. In addition, a lower PAPR is achieved compared to OFDMA case, which is an important merit in the uplink transmission due to the UE’s power resources constraint (limited battery power).
This project presents the description, design and the implementation of a 4-channel microphone array that is an adaptive sub-band generalized side lobe canceller (GSC) beam former uses for video conferencing, hands-free telephony etc, in a noisy environment for speech enhancement as well as noise suppression. The side lobe canceller evaluated with both Least Mean Square (LMS) and Normalized Least Mean Square (NLMS) adaptation. A testing structure is presented; which involves a linear 4-microphone array connected to collect the data. Tests were done using one target signal source and one noise source. In each microphone’s, data were collected via fractional time delay filtering then it is divided into sub-bands and applied GSC to each of the subsequent sub-bands. The overall Signal to Noise Ratio (SNR) improvement is determined from the main signal and noise input and output powers, with signal-only and noise-only as the input to the GSC. The NLMS algorithm significantly improves the speech quality with noise suppression levels up to 13 dB while LMS algorithm is giving up to 10 dB. All of the processing for this thesis is implemented on a computer using MATLAB and validated by considering different SNR measure under various types of blocking matrix, different step sizes, different noise locations and variable SNR with noise.
Transport sector is an essential driver of economic development and growth, and at the same time, one of the biggest contributors to climate change, responsible for almost a quarter of the global carbon dioxide emissions. The sector is 95 percent dependent on fossil fuels. International Energy Agency (IEA) scenarios present different mixes of fuels to decrease both dependence on fossil fuels and emissions, leading to a more sustainable future. The main alternative fuels proposed in the Blue map scenario, presented in the Energy Technologies Perspective 2008, were hydrogen and second-generation ethanol. An assessment of these fuels was made using the tools SLCA (Sustainability Life Cycle Assessment) and SWOT Analysis. A Framework for Strategic Sustainable Development (FSSD) is the background used to guide the assessment and to help structure the results and conclusions. The results aim to alert the transport sector stakeholders about the sustainability gaps of the scenario, so decisions can be made to lead society towards a sustainable future.
Fuzzy relation equations are becoming extremely important in order to investigate the optimal solution of the inverse problem even though there is a restrictive condition for the availability of the solution of such inverse problems. We discussed the methods for finding the optimal (maximum and minimum) solution of inverse problem of fuzzy relation equation of the form $R \circ Q = T$ where for both cases R and Q are kept unknown interchangeably using different operators (e.g. alpha, sigma etc.). The aim of this study is to make an in-depth finding of best project among the host of projects, depending upon different factors (e.g. capital cost, risk management etc.) in the field of civil engineering. On the way to accomplish this aim, two linguistic variables are introduced to deal with the uncertainty factor which appears in civil engineering problems. Alpha-composition is used to compute the solution of fuzzy relation equation. Then the evaluation of the projects is orchestrated by defuzzifying the obtained results. The importance of adhering to such synopsis, in the field of civil engineering, is demonstrated by an example.
To protect our health and environment from pollution, among others regulatory agencies in the European Union (EU) and legislation from the U.S. Environmental Protection Agency (EPA) has required that pollutants produced by diesel engines - such as nitrogen oxides (NOx), hydrocarbons (HC) and particulate matter (PM) - be reduced. The key emission reduction and control technologies available for NOx control on Diesel engines are combination of Exhaust Gas Recirculation (EGR) and Selective Catalytic Reduction (SCR). SCR addresses emission reduction through the use of Diesel Exhuast Fluid (DEF), which has a trade-name AdBlue. Which is 32.5% high purity urea and 67.5% deionized water, Adblue in the hot exhaust gas decomposes into ammonia (NH3) which then reacts with surface of the catalyst to produce harmless nitrogen(N2) and water (H20). Highest NOx conversion ratios while avoiding ammonia slip is achieved by Efficient SCR and accurate Urea Dosing System it’s therefore critical we model and simulate the UDS in order to analyze and gain holistic understanding of the UDS dynamic behavior. The process of Modeling and Simulating of Urea Dosing System is a result of a compromise between two opposing trends. Firstly, one needs to use as much mathematical models as it takes to correctly describe the fundamental principles of fluid dynamics such as, (1) mass is conserved (2), Newton’s second law and (3) energy is conserved, secondly the model needs to be as simple as possible, in order to express a simple and useful picture of real systems. Numerical model for the simulation of Urea Dosing System is implemented in GT Suite® environment, it is complete UDS Model (Hydraulic circuit and Dosing Unit) and it stands out for its ease of use and simulation fastness, The UDS model has been developed and validated using as reference Hilite Airless Dosing System at the ATC Lab, results provided by the model allow to analyze the UDS pump operation, as well the complete system, showing the trend of some important parameters which are difficult to measure such as viscosity, density, Reynolds number and giving plenty of useful information to understand the influence of the main design parameters of the pump, such as volumetric efficiency, speed and flow relations.
The use of vascular intersection aberration as one of the signs when monitoring and diagnosing diabetic retinopathy from retina fundus images (FIs) has been widely reported in the literature. In this paper, a new hybrid approach called the combined cross-point number (CCN) method able to detect the vascular bifurcation and intersection points in FIs is proposed. The CCN method makes use of two vascular intersection detection techniques, namely the modified cross-point number (MCN) method and the simple cross-point number (SCN) method. Our proposed approach was tested on images obtained from two different and publicly available fundus image databases. The results show a very high precision, accuracy, sensitivity and low false rate in detecting both bifurcation and crossover points compared with both the MCN and the SCN methods.
Synthetic Aperture Radar (SAR) image processing involves a two dimensional (2-D) Fourier Transform (FT) and the spectrum shape introduces high intensity sidelobes. These sidelobes may severely distort the image. Apodization technique can decrease the sidelobes level while preserving the image resolution. However, in Ultra wideband (UWB) SAR imaging, we have to reduce both orthogonal and non-orthogonal sidelobes. In this paper, a new linear window function has been presented based on analysis of different linear and non-linear apodization techniques. This new linear method controls both orthogonal and non-orthogonal sidelobes better than other conventional window functions. This method has been applied and verified with a real SAR image.
Ultra wideband (UWB) Synthetic Aperture Radar (SAR) holds huge possibilities for both terrestrial and celestial object sensing with excellent details which assists in science and technology. SAR systems associated with large antenna beamwidth, large signal bandwidth and low frequency operating in the VHF/UHF region is becoming gradually more popular because of their rising number of application in the areas of ground-penetrating radar (GPR) and foliage penetration radar (FOPEN). Apodization techniques in UWB SAR imaging have attracted significant interest in recent years for sidelobe suppression in SAR images. This technique is split into two groups: linear apodization and non-linear apodization. Linear apodization technique means to apply amplitude weighting functions in frequency domain prior to the final inverse Fourier transform requisite to appropriately focus on the SAR images. Both linear and non linear techniques can be used to suppress sidelobes level. Frequently used linear weighting functions are Hanning, Hamming and Blackman. Linear techniques can control the sidelobes level but image resolution reduces simultaneously. But non-linear techniques like Spatially Variant Apodization (SVA), Complex Duel Apodization and Dual-Apodization can suppress sidelobes and preserve the spatial resolution concurrently. However for these methods, it can be hard to understand how the output signal relates to input signal and also the phase information of image is lost. In this thesis paper, the main focus is, on apodization techniques to propose a new weighting function for sidelobe apodization and investigate it on real SAR images. In this thesis, we also study Impulse response (IPR) function for UWB SAR image processing. A two dimensional sinc function is used as an impulse response function for narrow band (NB) SAR system. This function can be obtained from a two dimensional Fourier Transform of a SAR image. This rectangular estimation is reasonable for narrow band and narrowbeam SAR. But for large bandwidth and wide integration angles, this approximation for the UWB SAR spectrum is not valid. It can provide erroneous SAR image quality measurements. To obtain precise image quality measurement, SAR image need to be generated for a range of different integration angle as UWB SAR systems are related with large integration angle to maintain azimuth focusing. So, in this work the choices of optimum windows have been investigated at different integration angles in order to see if there are large differences between NB SAR Apodization and UWB SAR Apodization.
Microfinance offers one way to combat poverty by providing access to credit and financial services to low-income borrowers. We argue that the interconnectedness of the socioeconomic and ecological system as well as the reliance on ecosystem services make it important to provide microcredit from a full sustainability perspective. We used the Framework for Strategic Sustainable Development, a scientific based systematic and strategic approach, to create a principle-based model of a microfinance institution operating in a socioeconomic and ecologically sustainable manner. This model was then compared with the circumstances in which these institutions currently operate. We then explored how taking a full sustainability perspective could meet current challenges and maximise opportunities. After a prioritisation process, we made recommendations on how these organisations could strategically move towards sustainability.
Focus on municipal level planning has increased in the recent years. Municipal governments are primarily responsible for such planning and they do have the biggest responsibility of driving the entire municipality towards sustainability. In this research project we provide a study on some of the gaps and challenges in the current procedures faced by a few municipalities within Southeast Sweden with respect to Energy and climate change planning and implementation. It was observed that the current engagement practices, communication, and alignment of goals could potentially hinder the municipality from achieving the overall goals of sustainability. Furthermore, a complementing facilitating platform was suggested that would give municipal governments an opportunity to intervene and address some of these gaps and challenges to establish structure and control on activities, towards a sustainable municipality.
By radiating bifrequency primary waves from two ultrasonic emitters with changing the phases of the primary waves, we can obtain the sound fields that are different from the usual in‐phase excitation. Especially, for the excitation of out‐phase by 180 degrees the difference frequency wave has the directivity of almost uniformity near the acoustic axis. Additionally, the sound pressure levels of the harmonic components of the difference frequency and the primary waves as well are suppressed by 10 dB and more
In this paper we investigate the block-type pilot channel estimation for orthogonal frequency-division multiplexing (OFDM) systems. The estimation is based on the minimum mean square error (MMSE) estimator and the least square (LS) estimator. We derive the MMSE and LS estimators’ architecture and investigate their performances. We prove that the MMSE estimator performance is better but computational complexity is high, contrary the LS estimator has low complexity but poor performance. For reducing complexity we proposed two different solutions which are the Simplified Least Square (SLS) estimator and the modified MMSE estimator. We evaluate estimator’s performance on basis of mean square error and symbol error rate for 16 QAM systems. We also evaluate estimator’s computational complexity.
The mobile wireless communication systems has been growing fast and continuously over the past two decades. Therefore, in order to fulfill the demand for this rapid growth, the standardization bodies along with wireless researchers and mobile operators around the world have been constantly working on new technical specifications.An important problem in modern communication is known as NP complete problem in the Maximum Likelihood (ML) detection of signals transmitting over Multiple Input Multiple Output channel of the OFDM transceiver system. Development of the Sphere Decoder (SD) as a result of the rapid advancement in signal processing techniques provides ML detection for MIMO channels at polynomial time complexity average case. There are weaknesses in the existing SDs. The sphere decoder performance is very sensitive for the most current proposals in order to choose the search radius parameter. At high spectral efficiencies SNR is low or as the problem dimension is high and the complexity coefficient can become very large too. Digital communications of detecting a vector of symbols has importance as, is encountered in several different applications. These symbols are as the finite alphabet and transmitted over a multiple-input multiple-output (MIMO) channel with Gaussian noise. There are no limitation to the detection of symbols spatially multiplexed over a multiple-antenna channel and the multi user detection problem. Efficient algorithms are considered for the detection problems and have recognized well. The algorithm of sphere decoder, orders has optimal performance considering the error probability and this has proved extremely efficient in terms of computational complexity for moderately sized problems in case of signal to noise ratio. At high SNR the algorithm has a polynomial average complexity and it is understood the algorithm has an exponential worst case complexity. The efficiency of the algorithm is ordered the exponential rate derivation of growth. Complexity is positive for the finite SNR and small in the high SNR. To achieve the sphere decoding solution applying Schnorr-Euchner by Maximum likelihood method , Depth-first Stack-based Sequential decoding is used. This thesis focuses on the receiver part of the transceiver system and takes a good look at the near optimal algorithm for sphere detection of a vector of symbols transmitted over MIMO channel. The analysis and algorithms are general in nature.
This thesis report is a research effort with Ericsson’s devices and internal documents. In essence this thesis report contributes with a perspective to understand the power system of Radio Base Station and its features. The overall research aim is to understand the existing power system and its features and to propose new software and hardware features. A lot of investigations have been done with the Functional Specification and Requirement Specification documents for analysis of the present features. The main goal is to identify software features and their benefits to customer. After analysing the present features new features were proposed. For the proposal many steps were taken into consideration including cost and system information. Also some hardware changes have been required. With the new proposed features, the power system will perform better with different environments and also some of the proposals were improvements of the existing features. The proposed features are mostly focused on power saving and cost to benefit the customer.
In this Master thesis work two types of ventilation system, mixed system and displacement system at the factory premises of Volvo Cars Body Components (VCBC) are investigated. A computer simulation technique was implemented to study the behavior of air movement and temperature distribution inside the factory for the two systems. The commercial CFD program Flovent is used for simulation purpose. Model verification was carried out with the measurements made. Results showed quite good agreement between these two values. The current model has then been used to predict the temperature distributions and air flow movement for different climate scenarios. Energy calculations were also made in order to find out the energy used by two systems annually. The results from the simulations showed that the displacement system gave better performance in every case in thermal comfort aspect, whereas in the energy aspect it was found that the displacement system used more energy annually compared to mixed system.
There is an overall consensus that the poor governance and corruption plaguing many developing nations are main inhibitors to progress. These inhibitors also lead to the overwhelming feelings of desperation, apathy, and determinism. International development assistance programs utilizing capacity building have been created to deal with sustainable development issues in the developing world. Often these programs are fragmented and address results, not the causes, of problems. This study assesses how existing community development approaches could be aided through a strategic sustainable development perspective. A majority of the research involved creation of a holistic innovative community development approach, which encourages transformational change and effective leadership, and comparison of that to an existing community development approach. Strengths and limitations were observed through this comparison and generic recommendations were created to support current approaches. The study found that existing development assistance strategies are effective at building capacity and helping communities, but encompassing a more holistic perspective could align planning and decision-making with socio-ecological sustainability and thereby support mid- and long-term progress.
Seamless communication is becoming the main aspect for the next generation of the mobile and wireless networks. Roaming among multiple wireless access networks connected together through one IP core makes the mobility support for the internet is very critical and more important research topics nowadays. Mobile IP is one of the most successful solutions for the mobility support in the IP based networks, but it has poor performance in term of handover delay. Many improvements have been done to reduce the handover delay, which result in two new standards: the Hierarchical MIP (HMIP) and the Fast MIP (FMIP), but the delay still does not match the seamless handover requirements. Finally Seamless MIP (S-MIP) has been suggested by many work groups, which combine between an intelligent handover algorithm and a movement tracking scheme. In This thesis, we show the handover delay reduction approaches, specifically the Seamless Mobile IP. The thesis studies the effects of the S-MIP in the handover delay and the network performance as well. A simulation study takes place to compare between the standard MIP and the new suggested S-MIP protocol in term of handover delay, packet loss and bandwidth requirement. The thesis concludes with the analyzing of the simulation results, evaluating the S-MIP performance and finally gives some suggestions for the future work.
Group classification of the perturbed nonlinear filtration equation is performed assuming that the perturbation is an arbitrary function of the dependent variable. The nonlinear self-adjointness of the equation under consideration is investigated. Using these results, the approximate conservation laws are constructed.
In the field of signal processing adaptive filtering is a major subject which has vast applications in speech processing e.g. speech coding, speech enhancement, echo cancellation and interference. Echo is the major problem in the communication systems. There are two major types of echoes hybrid and acoustic echoes. In order to remove these echoes the most important method for removing these echoes is through cancellation. Adaptive filters are used to estimate the replication of echoes and then subtracted from the infected signal. . We introduced subband filters to improve the performance of adaptive filter (time domain). Due to small adaptive filters in the subband filter banks, we can improve the reduction of complexity, computational and convergence level as compared with others. The major goal of this thesis is to present the echo cancellation using the multiband subband adaptive filtering and also compare the performance with NLMS and Improved PNLMS using different impulse responses. PMSAF algorithm behaves continuously better convergense rate with excitation signal (colored noise and speech signal) for both impulse responses (sparse and dispersive) as compared with IPNLMS and NLMS algorithms.
Human-influenced climate change is rapidly accelerating and continues to threaten to human existence. Global migration is leading to increasingly multicultural urban populations. This paper ties these two issues together through the lense of engagement. The thesis argues that a Framework for Strategic Sustainable Development (FSSD) can be used to plan strategies to engage multicultural communities towards second commitment Kyoto targets and be an opportunity for meeting community needs for social sustainability. The research took place in Sweden through interviews and focus groups. Key findings address systematic exclusion and the potential of inquiry to discover barriers and leverage points. The resulting set of guidelines for municipalities utilizes the full spectrum of engagement (inform, consult, involve, collaborate, empower) and the FSSD to enhance existing climate change action plans towards maximum participation for fulfilling Kyoto Protocol mandates.
Cognitive Radio (CR) has been proposed as a promising and effective technology to improve radio spectrum utilization. It can change its transmitter parameters depending on the environment in which it operate based on interaction. In CR, a number of different methods of spectrum sensing are used to identify the presence of signal transmission. Among them, the multitaper method (MTM), has been investigated in this thesis paper at the same time with other sensing methods, recently seems to be the best choice for spectrum sensing CR because of its accurate identification and estimation, quick computation, and regularization. This thesis paper is examining how CR can be utilized in short range systems based on Ultra-Wideband (UWB). UWB is a promising technology in wireless communication use for high speed data transmission with low power utilization or long distance localization in both military, radar, sensor, data collection, tracking or commercial application. UWB has the ability to move between very low data rate or very high data rate, short range distance or long range distance applications. Impulse radio UWB (IR-UWB) shows some impressive characteristics in short-range communication systems with varieties of throughput option including high data rates. The strong synergy between the aims of CR and features of IR-UWB has been shown in this thesis. Our key objective is to understand how CR can be applied to UWB systems.
In this paper, we investigate the average symbol error probability (SEP) of fixed decode-and-forward relay networks over independent but not identically distributed Nakagami-m fading channels. We have derived closed form expression of SEP for general rectangular quadrature amplitude modulation (QAM) under relay selection scheme where only the best relay forwards message from the source to the destination. The expressions are in terms of hypergeometric series which can be efficiently numerically evaluated. The numerical results are validated with Monte-Carlo simulations.
The sustainability challenge currently poses one of the biggest challenges society has ever faced. With declining natural resources, climate change and a rising human population the need to change humanity’s trajectory towards sustainability has never been more urgent. A greater degree of engagement in sustainability by people in positions of power and influence within society is necessary if this transition is to occur quickly. This thesis explores the dynamics of Outdoor Experiential Learning Processes (OELPs) as applied to individuals from a professional background. The purpose is to assess how the OELP can be designed within society to engage influential professionals in sustainability. The research combines the existing powerful approach of the OELP with the Framework for Strategic Sustainable Development (FSSD). Strategic recommendations are made for how to achieve greater engagement in sustainability amongst OELP participants for a more sustainable future.
Communication patterns in nature were studied in order to address the challenge of effectively communicating sustainability messages. Fourteen patterns were found in nature and translated into user-friendly guidelines called Guidelines for Effective Communication of Sustainability Messages. These Guidelines were given to sustainability experts and peers for overall feedback and insights. Their responses showed that these Guidelines could be used to improve communication of sustainability messages by using them as a checklist and a design tool when designing messages and methods for communicating sustainability. Using these Guidelines as a tool within the Framework for Strategic Sustainable Development (FSSD) could also help people better understand today’s sustainability challenges and the need for adopting a strategic approach used within the FSSD.
Behaviour change initiatives have largely failed in communicating the urgency of the sustainability challenge to the public and thus generate achange of behaviour. Religious communities have achieved remarkable behaviour change in situations where non-faith-based communication failed (Palmer and Finlay 2003). This paper explores what Christian belief contributes to moving society towards sustainability through the lens of the Framework for Strategic Sustainable Development (FSSD). We focus on three themes: (1) the definition of sustainability, (2) the religious motivation for and (3) actions towards sustainability. A number of religious leaders are interviewed and the religious community surveyed. Findings show that religious concepts such as stewardship and the Golden Rule are key motivations for can give guidance on sustainability. However, these concepts are not consciously exploited. Further more, both religious leaders and people lack a full understanding of sustainability and are not strategic about moving towards sustainability. We conclude that religious communities could greatly benefit from adopting a strategic sustainable development (SSD) approach.
Transportation is good for people, but it needs a social system shift in combination with sustainable technologies in order to move towards a sustainability vision. To explore how that can be done, the authors first found out about both national and municipal sustainability visions and identified a range of social and technological solutions for long and short term use. The exploration of how municipal planning of transportation can be improved lead to the conclusion that planning for transportation in Swedish municipalities can be made more sustainable when conducting the ABCD-method within the framework for strategic sustainable development. To enhance that, the authors merged the five subsystems developed for sustainable traffic solutions and the PESTEL-method. That resulted in the S-E-A-T model that informed the content of a prioritisation tool and also provides structure to the brainstorming sessions within the ABCD-method. The combination of the ABCD method, the S-E-A-T model and the expanded guiding questions form a robust approach for strategic planning of sustainable transportation rooted in a bird´s eye and systems perspective and ultimately based on backcasting from the principles of sustainability. Further testing is though recommended to assess and refine its usefulness and applicability.
The use of remote labs in undergraduate courses has been reported in literature several times since the mid 90's. Nevertheless, very few articles present results about the learning gains obtained by students using them, especially with a large number of students, thus suggesting a lack of data concerning their pedagogical effectiveness. This paper addresses such a gap by presenting some preliminary results concerning the use of a remote laboratory, known as VISIR, in a large undergraduate course on Applied Physics, with over 500 students enrolled.
The present work has been done after a question defined by the author about the approaches of the human’s heart simulation. In this way, the structure and function of the heart have been investigated to understand the anatomy and physiology of the heart. Then, a literature study about the heart simulation has been done to figure out which modeling approaches have been applied in this way and how they have been implemented to represent the heart function. We have realized that lamped parameter, two dimensional and three dimensional models have been applied for this purpose and the Immersed Boundary Method introduced by C.S.Peksin has been considered as a powerful numerical method for simulation of the nonlinear fluid-structure interactions which is the base of one of the advanced three dimensional modeling approaches of the heart function. Besides, some of the applicable tools for the simulation of heart function are addressed.