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  • 1.
    Adesina, Owolabi Abiona
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Statistical Modelling and the Fokker-Planck Equation2008Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    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.

  • 2.
    Ahmed, Uzair
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Saqib, Muhammad
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Optimal Solutions Of Fuzzy Relation Equations2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    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.

  • 3.
    Ajayi, Taiwo Seun
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Mobile Satellite Communications: Channel Characterization and Simulation2007Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Abstract: The channel characterization of a mobile satellite communication which is an important and fast growing arm of wireless communication plays an important role in the transmission of information through a propagation medium from the transmitter to the receiver with minimum barest error rate putting into consideration the channel impairments of different geographical locations like urban, suburban, rural and hilly. The information transmitted from satellite to mobile terminals suffers amplitude attenuation and phase variation which is caused by multipath fading and signal shadowing effects of the environment. These channel impairments are commonly described by three fading phenomena which are Rayleigh fading, Racian fading and Log-normal fading which characterizes signal propagation in different environments. They are mixed in different proportions by different researchers to form a model to describe a particular channel. In the thesis, the general overview of mobile satellite is conducted including the classification of satellite by orbits, the channel impairments, the advantages of mobile satellite communication over terrestrial. Some of the major existing statistical models used in describing different type of channels are looked into and the best out of them which is Lutz model [6] is implemented. By simulating the Lutz model which described all possible type of environments into two states which represent non-shadowed or LOS and shadowed or NLOS conditions, shows that the BER is predominantly affected by shadowing factor.

  • 4.
    Akbar, Zeeshan
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ali, Asar
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Evaluation of AODV and DSR Routing Protocols of Wireless Sensor Networks for Monitoring Applications2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    In all the three scenarios of small, large and very large networks AODV gives considerably less delay as compared to DSR. AODV outperforms DSR with prominent difference in delay. In terms of delay the network size has an impact on both AODV and DSR performance.  The throughput rate of AODV in small and large networks exceeds with a little margin than the throughput rate of DSR but in case of large networks the difference is prominent and AODV by far performs better than DSR.

  • 5. Alaves, Dimas
    et al.
    Machado, Renato
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    da Costa, Daniel Benevides
    Legg, Andrei Piccinini
    Uchoa-Filho, Bartolomeu F.
    A dynamic hybrid antenna/relay selection scheme for the multiple-access relay channel2014Ingår i: 2014 11TH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATIONS SYSTEMS (ISWCS), IEEE , 2014, s. 594-599Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose a dynamic hybrid antenna/relay selection scheme for multiple-access relay systems. The proposed scheme aims to boost the system throughput while keeping a good error performance. By using the channel state information, the destination node performs a dynamic selection between the signals provided by the multi-antenna relay, located in the inter-cell region, and the relay nodes geographically distributed over the cells. The multi-antenna relay and the single-antenna relay nodes employ the decode-remodulate-and-forward and amplify-and-forward protocols, respectively. Results reveal that the proposed scheme offers a good tradeoff between spectral efficiency and diversity gain, which is one of the main requirements for the next generation of wireless communications systems.

  • 6.
    Alipour, Philip Baback
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ali, Muhammad
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    An Introduction and Evaluation of a Lossless Fuzzy Binary AND/OR Compressor2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Vi rapporterar en ny förlustfri komprimering algoritm (MUL) för att genomföra förutsägbart-fast komprimering värden. Den luddiga binär och-eller algoritm (FBAR), syftar bland annat att införa en ny modell för regelbunden och superdense kodning i klassiska och kvantmekaniska information teori. Klassiska kodning på x86-maskiner inte skulle räcka teknik för maximal LDC att skapa fasta värden av Cr >= 2:1. Men den nuvarande modellen utvärderas för att tjäna flerdimensionella LDC med fast värde generationer, där de populära metoder som används i probabilistiska LDC, såsom Shannon entropi. De närvarande in entropi är av "fuzzy binära" i en 4D blixtkub lite flagga modell, med en produkt värde av minst 50% komprimering. Vi har genomfört komprimering och simulerade den tryckfall fasen för förlustfri versioner av FBAR logik. Jämförde vi ytterligare vår algoritm med de resultat som andra kompressorer. Vår statistiska testet visar att den presenterade algoritmen mutably och betydligt konkurrerar med andra LDC algoritmer på båda, tidsmässiga och geografiska faktorer av kompression. Den nuvarande algoritmen är en steppingstone att kvantinformationsteknik modeller lösa komplexa negativa entropies, vilket ger dubbel-effektiva LDC> 87,5 besparingar utrymme.

  • 7. Alves, Dimas I.
    et al.
    Machado, Renato
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Legg, Andrei P.
    Uchoa-Filho, Bartolomeu F.
    Cooperative multiple-access scheme with antenna selection and incremental relaying2014Ingår i: 2014 INTERNATIONAL TELECOMMUNICATIONS SYMPOSIUM (ITS), São Paulo: IEEE , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    A cooperative multiple-access scheme for wireless communications systems with antenna selection and incremental relaying is proposed. The scheme aims to improve the system throughput while preserving good performance in terms of bit error rate. The system consists of N nodes which send their information to both the destination node and the multiple-antenna relay station. Based on the channel state information, the destination node decides whether or not relaying will be performed. When the relaying is performed, the decode-remodulate-and-forward protocol is used with the best antenna. Results reveal that the proposed scheme achieves a good tradeoff between throughput and bit error rate, which makes suitable to be considered for multi-user networks.

  • 8.
    Andersson, Björn
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för programvarusystem.
    Persson, Marie
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för programvarusystem.
    Software Reliability Prediction – An Evaluation of a Novel Technique2004Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Along with continuously increasing computerization, our expectations on software and hardware reliability increase considerably. Therefore, software reliability has become one of the most important software quality attributes. Software reliability modeling based on test data is done to estimate whether the current reliability level meets the requirements for the product. Software reliability modeling also provides possibilities to predict reliability. Costs of software developing and tests together with profit issues in relation to software reliability are one of the main objectives to software reliability prediction. Software reliability prediction currently uses different models for this purpose. Parameters have to be set in order to tune the model to fit the test data. A slightly different prediction model, Time Invariance Estimation, TIE is developed to challenge the models used today. An experiment is set up to investigate whether TIE could be found useful in a software reliability prediction context. The experiment is based on a comparison between the ordinary reliability prediction models and TIE.

  • 9.
    AWOMEWE, Alaba-Femi
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för matematik och naturvetenskap.
    Monitoring the volatility in a process which reflects trading in the financial market2007Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Recently, the financial market has become an area of increased research interest for mathematician and statisticians. The Black and Scholes breakthrough in this area triggered a lot of new research activity. Commonly the research concerns the log returns of assets (shares, bond, foreign exchange, option). The variation in the log returns is called volatility and it is widely studied and because of its relevance for applications in the financial world. The volatility is mostly used for measuring the risk and also for forecasting future prices. In this research work a process of trading activities is considered. It is assumed that at a random time-point a parameter change in the laws of the trading occurs, indicating changed trading behaviour. For inferential matters about the process it is of vital importance to be able to state that such change has occurred quickly and accurately. The methods used to this end are called stopping rules which signal alarm as soon as some statistics based on-line observations goes beyond some boundary. The model considered for this process of log returns is the family of Autoregressive Conditional Heteroskedastic (ARCH) model. It is widely accepted that this well describes a lot of phenomena in the financial market. In this work statements about this process will be derived, the stopping rule will be defined, evaluated and their properties discussed.

  • 10.
    Banadaki, Davood Dehgan
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Durmush, Sunay Sami
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Zahiri, Sharif
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Statistical Assessment of Uncertainties Pertaining to Uniaxial Vibration Testing and Required Test Margin for Fatigue Life Verification2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In the automotive industry uniaxial vibration testing is a common method used to predict the lifetime of components. In reality truck components work under multiaxial loads meaning that the excitation is multiaxial. A common method to account for the multiaxial effect is to apply a safety margin to the uniaxial test results. The aim of this work is to find a safety margin between the uniaxial and multiaxial testing by means of virtual vibration testing and statistical methods. Additionally to the safety margin the effect of the fixture’s stiffness on the resulting stress in components has been also investigated.

  • 11.
    Butt, Rehan
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Numerical Aspects of Extended Curve of Growth2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In curve of growth, traditionally equivalent width is found for absorption lines of Gaussian, Lorentz and Voigt profile against flat continuum. Here, absorption against non-flat distributions is examined. These non-flat distributions are Gaussian and Lorentz distribution. Analytically equivalent widths for absorption against non-flat continuum are complicated integrals. It is impossible to solve these integrals analytically so I have solved them numerically. At low μ the absorption is independent on profile while the growth of absorption depends on profile at high μ, where μ is width.

  • 12.
    Chittajallu, Sai Kiran
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    MOBILE PHONE ACOUSTICS: PERFORMANCE EVALUATION OF SPECTRAL SUBTRACTION AND ELKO’S ALGORITHM USING SPEECH QUALITY METRICS2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In recent years a great deal of effort has been expended to develop methods that determine the quality of speech through the use of comparative algorithms. These methods are designed to calculate an index value of quality that correlates to a mean opinion score given by human subjects in evaluation sessions. In this work PESQ (ITU-T Recommendation P.862) which is the new ITU-T benchmarking for objective measurement of speech quality. In mobile phone acoustics, the presence of noise and room reverberation play a vital role in degrading the speech signal and therefore, spectral subtraction and Elko’s beamformer has been used for noise reduction. Weighted Overlap and Add method (WOLA) filter bank is used for frequency domain analysis of the speech signal. Elko’s algorithm is used for designing a differential microphone array, implemented by connecting two omni directional elements to form back-to-back cardioid directional microphones. The output from the Elko’s beamformer is then used as an input to spectral subtraction based on minimum statistics reducing further noise and to enhance the quality of the speech signal. The performance of this system is analysed by calculating the value of PESQ as a speech quality measure. The better the value the PESQ, the better is the output speech quality. Signal to Noise Ratio (SNR) is used to measure the amount of noise in the restored speech signal. Reverberation Index is also used to measure the amount of reverberation effect present in the restored speech signal.

  • 13.
    Dimkovski, Zlate
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Characterization of a Cylinder Liner Surface by Roughness Parameters Analysis2006Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Cylinder liner surface topology greatly affects oil consumption and wear of engines. Surface optimization would be greatly facilitated by automatic quality control. Surface roughness definitions, parameters, and measurement techniques were reviewed and samples of different Volvo truck engine cylinder liner types were measured. Routines for extracting and computing groove parameters, useful in the automation of quality control in production, were developed, implemented in MATLAB and applied on the samples. The principles of the last two steps procedures needed to fully automate the surface grading by roughness parameters analysis were described.

  • 14. Eriksson, Per-Erik
    et al.
    Pesämaa, Ossi
    Blekinge Tekniska Högskola, Sektionen för management.
    Buyer-supplier integration in project-based industries2013Ingår i: The journal of business & industrial marketing, ISSN 0885-8624, E-ISSN 2052-1189, Vol. 28, nr 1, s. 29-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose – The purpose of the study is to propose and test a buyer-supplier integration model, based on clients' collaborative purchasing practices, in a project-based industry. Design/methodology/approach – Hypotheses regarding the relationships among the three variables – i.e. incentive-based payment (IBP), partner selection (PS) based on multiple criteria, and joint action (JA) – are tested using structural equation modeling. Empirical data was collected through two survey rounds of 87 and 106 Swedish construction clients. Findings – The test of the proposed theoretical model receives strong empirical support, indicating that IBP should be coupled with PS based on multiple criteria in order to facilitate JA. Furthermore, it is seen that the occurrence of JA is higher in 2009 than in 2006 and that this is achieved through increased use of IBP. Research limitations/implications – The hypothesized and tested model provides a theoretical contribution, indicating how to facilitate buyer-supplier integration in project-based industries. In future studies it would be useful to adopt a multiple-informant approach, also including suppliers as respondents in order to capture their views on integration. Practical implications – An important managerial implication is that public clients need to improve their understanding of how to design bid proposals and evaluate bids based on multiple criteria instead of lowest price, without infringing public procurement acts. Originality/value – This paper offers unique contributions by addressing a gap in the relationship marketing literature and a lack of quantitative studies of buyer-supplier relationships in project-based industries.

  • 15. Erman, David
    et al.
    Ilie, Dragos
    Popescu, Adrian
    BitTorrent Traffic Characteristics2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports on a measurement and modeling study of session and message characteristics of BitTorrent traffic. BitTorrent is a Peer-to-peer (P2P) replication and distribution system developed as an alternative to the classical client-server model to reduce the load on content servers and networks. Results are reported on measurement, modeling and analysis of application and link layer traces collected at the Blekinge Institute of Technology (BTH) and a local ISP in Sweden. Link layer traces and application logs were collected, modeled and analyzed using a dedicated measurement infrastructure developed at BTH to collect P2P traffic. New results are reported on important session and message characteristics of BitTorrent, i.e., session interarrivals, sizes and durations, request rates and response times. Our results show that session interarrivals can be accurately modeled by a second-order hyper-exponential distribution while session durations and sizes can be reasonably well modeled by various mixtures of the Log-normal and Weibull distributions. Response times have been observed to be modeled by a dual Log-normal mixture, while request rates are modeled as dual Gaussian distributions.

  • 16.
    Ewö, Christian
    Blekinge Tekniska Högskola, Institutionen för programvaruteknik och datavetenskap.
    A machine learning approach in financial markets2003Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this work we compare the prediction performance of three optimized technical indicators with a Support Vector Machine Neural Network. For the indicator part we picked the common used indicators: Relative Strength Index, Moving Average Convergence Divergence and Stochastic Oscillator. For the Support Vector Machine we used a radial-basis kernel function and regression mode. The techniques were applied on financial time series brought from the Swedish stock market. The comparison and the promising results should be of interest for both finance people using the techniques in practice, as well as software companies and similar considering to implement the techniques in their products.

  • 17.
    FADAHUNSI, Adetokunbo Ibukun
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Change point detection in an Ornstein-Uhlenbeck process (a reflection of trading in financial markets)2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The financial market has become an area of increasing research interest for mathematicians and statisticians in recent years. Mathematical models and methods are increasingly being applied to study various parameters of the market. One of the parameters that have attracted lots of interest is `volatility'. It is the measure of variability of prices of instruments (e.g. stock, options etc.) traded in the market. It is used mainly to measure risk and to predict future prices of assets. In this paper, the volatility of financial price processes is studied using the Ornstein-Uhlenbeck process. The process is a mean reverting model which has good and well documented properties to serve as a model for financial price processes. At some random time point, a parameter change in the distribution of the price process occurs. In order to control the development of prices, it is important to detect this change as quickly as possible. The methods for detecting such changes are called `stopping rules'. In this work, stopping rules will be derived and analysed. Using simulations and analytical methods, the properties of these stopping rules will be evaluated.

  • 18.
    farooq, Muhammad
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Raja, Abdullah Aslam
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Genetic Algorithm for Selecting Optimal Secondary Users to Collaborate in Spectrum sensing2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Cognitive Radio is an innovative technology that allows the secondary unlicensed users to share the spectrum with licensed primary users to utilize the spectrum. For maximum utilization of spectrum, in cognitive radio network spectrum sensing is an important issue. Cognitive user under extreme shadowing and channel fading can‟t sense the primary licensed user signal correctly and thus to improve the performance of spectrum sensing, collaboration between secondary unlicensed users is required. In collaborative spectrum sensing the observation of each secondary user is received by a base station acting as a central entity, where a final conclusion about the presence or absence of the primary user signal is made using a particular decision and fusion rule. Due to spatially correlated shadowing the collaborative spectrum sensing performance decreases, and thus optimum secondary users must be selected to, not only improve spectrum sensing performance but also lessen the processing overhead of the central entity. A particular situation is depicted in the project where according to some performance parameters, first those optimum secondary users that have enough spatial separation and high average received SNR are selected using Genetic Algorithm, and then collaboration among these optimum secondary users is done to evaluate the performance. The collaboration of optimal secondary user providing high probability of detection and low probability of false alarm, for sensing the spectrum is compared with the collaboration of all the available secondary users in that radio environment. At the end a conclusion has been made that collaboration of selected optimum secondary users provides better performance, then the collaboration of all the secondary users available.

  • 19.
    Ghadami, Soheil
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    The Evaluation of the Gaussian Mixture Probability Hypothesis Density Filter Applied in a Stereo Vision System2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this thesis, the performance of the Gaussian Mixture Probability Hypothesis Density (GM-PHD) filter using a pair of stereo vision system to overcome label discontinuity and robust tracking in an Intelligent Vision Agent System (IVAS) is evaluated. This filter is widely used in multiple-target tracking applications such as surveillance, human tracking, radar, and etc. A pair of cameras is used to get the left and right image sequences in order to extract 3-D coordinates of targets’ positions in the real world scene. The 3-D trajectories of targets are tracked by GM-PHD filter. Many tracking algorithms fail to simultaneously maintain stability of tracking and label continuity of targets, when one or more targets are hidden for a while to camera’s view. The GM-PHD filter performs well in tracking multiple targets; however, the label continuity is not maintained satisfactorily in some situations such as full occlusion and crossing targets. In this project, the label continuity of targets is guaranteed by a new method of labeling, and the simulation results show satisfactory results. A random walk motion is used to validate the ability of the algorithm in tracking and maintaining targets’ labels. In order to evaluate the performance of the GM-PHD filter, a 3-D spatial test motion model is introduced. Here, the two target trajectories are generated in a way that either occlusion or crossing occurs in some time intervals. Then, the two key parameters, angular velocity and motion speed, are used to evaluate the performance of algorithm. The simulation results for two moving targets in occlusion and crossing show that the proposed system not only robustly tracks them, but also maintains the label continuity of two targets.

  • 20.
    Ghassemi, Nooshin Haji
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Analytic Long Term Forecasting with Periodic Gaussian Processes2014Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In many application domains such as weather forecasting, robotics and machine learning we need to model, predict and analyze the evolution of periodic systems. For instance, time series applications that follow periodic patterns appear in climatology where the CO2 emissions and temperature changes follow periodic or quasi-periodic patterns. Another example can be in robotics where the joint angle of a rotating robotic arm follows a periodic pattern. It is often very important to make long term prediction of the evolution of such systems. For modeling and prediction purposes, Gaussian processes are powerful methods, which can be adjusted based on the properties of the problem at hand. Gaussian processes belong to the class of probabilistic kernel methods, where the kernels encode the characteristics of the problems into the models. In case of the systems with periodic evolution, taking the periodicity into account can simplifies the problem considerably. The Gaussian process models can account for the periodicity by using a periodic kernel. Long term predictions need to deal with uncertain points, which can be expressed by a distribution rather than a deterministic point. Unlike the deterministic points, prediction at uncertain points is analytically intractable for the Gaussian processes. However, there are approximation methods that allow for dealing with uncertainty in an analytic closed form, such as moment matching. However, only some particular kernels allow for analytic moment matching. The standard periodic kernel does not allow for analytic moment matching when performing long term predictions. This work presents an analytic approximation method for long term forecasting in periodic systems. We present a different parametrization of the standard periodic kernel, which allows us to approximate moment matching in an analytic closed form. We evaluate our approximate method on different periodic systems. The results indicate that the proposed method is valuable for the long term forecasting of periodic processes.

  • 21.
    Gillani, Syed Fakhar Uz Zaman
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Investigation of End User IPTV Quality for Content Delivered in MPEG-2 Transport Stream2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    IPTV or Internet Protocol Television is a system where digital television is delivered to the end user using the Internet Protocol. It relies on the same technologies that are used for computer networks and adds new possibilities, such as video on demand, on top of the traditionally broadcasted TV. Video content for IPTV is typically compressed using a MPEG-2 or H.264 (MPEG-4 part 10) compression and sent in an MPEG-2 transport stream over IP. Since TV is a "real time service" packets are delivered using a simple unreliable transmission model and packets may arrive out of order or be lost. Lost packets are normally not re-transmitted since they anyhow would arrive too late to be useful and packet loss will thus decrease perceived quality for the end user. The Master thesis is an investigation of the parameters that affect the perceived quality in MPEG-2 Transport Stream (TS). The aim of the thesis is to develop an objective parametric model1 that can estimate the perceived quality at transport layer. The thesis work includes experimentation performed on High Definition (HD) video sequences with various bit rates and packet loss ratios (PLR).

  • 22.
    Gomez, Aldo Fabricio Gutierrez
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för matematik och naturvetenskap.
    Mathematical Analysis of Financial Markets2006Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Basic mathematic analysis of how financial markets work and different valuation models such as the Stochastic Market Price Estimator, valuation model created by the author.

  • 23. Gosson, Maurice de
    Phase Space Quantization and the Uncertainty Principle,2003Ingår i: Physics Letters : Section A, ISSN 0375-9601 , Vol. 317, nr 5-6, s. 365-369Artikel i tidskrift (Refereegranskat)
    Abstract [sv]

    symplektisk topologi

  • 24.
    Grunditz, David
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Implementation av CUSUM/SPRT-algoritm för kvalitetsövervakning i realtid av robotsvetsning2005Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Under början av 1990-talet inledde Volvo Personvagnar i Olofström en process där övervakning av robotiserad MIG/MAG-svetsning var i fokus. Det ledde fram till ett forskningsprojekt som resulterade i att Stefan Adolfsson, Lunds tekniska högskola/Blekinge tekniska högskola, 1998 presenterade avhandlingen Automatic Quality Monitoring in GMA Welding using Signal Processing Methods [5]. I den presenterades ett SPRT-baserat övervakningskoncept för övervakning av MIG/MAG-svetsning med kort- och spraybåge. För att få fram ett kostnadseffektivt övervakningssystem uppkom tanken att använda vanliga PC-datorer som plattform. De erbjuder hög beräkningskapacitet till förhållandevis låg kostnad. Examensarbetets mål är att implementera det SPRT-baserade övervakningskonceptet i LabVIEW på en PC och utvärdera realtidsegenskaperna. Till detta tillkom även uppgiften att kartlägga motsvarande övervakningssystem på marknaden. Den färdiga implementationen övervakar svetsspänningens och svetsströmmens medelvärde respektive varians. Totalt har fyra olika SPRT-algoritmkoncept implementerats där alla är modifierade i förhållande till den som presenteras i ovan nämnda avhandling. Två av algoritmkoncepten är framtagna under detta arbetes gång och är avsedda för att minimera antalet falsklarm orsakade av naturliga systematiska variationer. Eftersom fyra olika SPRT-algoritmkoncept har använts för att övervaka svetsspänningens och svetsströmmens medelvärde respektive varians medför det att totalt 16 SPRT-algoritmer har implementerats vilka arbetar parallellt. Utvärderingen av implementationen visar att en vanlig PC-dator är tillräcklig för realtidsövervakning. Vidare visar utvärderingen också att endast två av SPRT-algoritmkoncepten är lämpliga att använda för svetsövervakning. Marknadskartläggningen av övervakningssystem för MIG/MAG-svetsning fann ett mindre antal system som kan konkurrera.

  • 25.
    Haider, Iqbal Hasan
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Rabby, MD. Fazla
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Performance Analysis of Cognitive Radio Network over SIMO System2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    As resources are limited, radio spectrum becomes congested due to the growth of wireless applications. However, measurements address the fact that most of the licensed spectrums experience low utilization even in intensively teeming areas. In the exertion to improve the utilization of the limited spectrum resources, cognitive radio networks have emerged as a powerful technique to resolve this problem. There are two types of user in cognitive radio networks (CRNs) named as primary user (PU) and secondary user (SU). Therein, the CRN enables the SU to utilize the unused licensed frequency of the PU if it possibly finds the vacant spectrum or white space (known as opportunistic spectrum access). Alternatively, SU can transmit simultaneously with the PU provided that transmission power of SU does not cause any harmful interference to the PU (known as spectrum sharing systems). In this thesis work, we study fundamental knowledge of the CRNs and focus on the performance analysis of the single input multiple output (SIMO) system for spectrum sharing approach. We assume that a secondary transmitter (SU-Tx) has full channel state information (CSI). The SU-Tx can adjust its transmit power not to cause harmful interference to the PU and obtain an optimal transmit rate. In particular, we derive the closed-form expressions for the cumulative distribution function (CDF), outage probability and an analytical expression for symbol error probability (SEP).

  • 26.
    Haider, Syed Imran
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Shahzad, Raja M. Khurram
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Detection of Spyware by Mining Executable Files2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Malicious programs have been a serious threat for the confidentiality, integrity and availability of a system. Different researches have been done to detect them. Two approaches have been derived for it i.e. Signature Based Detection and Heuristic Based Detection. These approaches performed well against known malicious programs but cannot catch the new malicious programs. Different researchers tried to find new ways of detecting malicious programs. The application of data mining and machine learning is one of them and has shown good results compared to other approaches. A new category of malicious programs has gained momentum and it is called Spyware. Spyware are more dangerous for confidentiality of private data of the user of system. They may collect the data and send it to third party. Traditional techniques have not performed well in detecting Spyware. So there is a need to find new ways for the detection of Spyware. Data mining and machine learning have shown promising results in the detection of other malicious programs but it has not been used for detection of Spyware yet. We decided to employ data mining for the detection of spyware. We used a data set of 137 files which contains 119 benign files and 18 Spyware files. A theoretical taxonomy of Spyware is created but for the experiment only two classes, Benign and Spyware, are used. An application Binary Feature Extractor have been developed which extract features, called n-grams, of different sizes on the basis of common feature-based and frequency-based approaches. The number of features were reduced and used to create an ARFF file. The ARFF file is used as input to WEKA for applying machine learning algorithms. The algorithms used in the experiment are: J48, Random Forest, JRip, SMO, and Naive Bayes. 10-fold cross-validation and the area under ROC curve is used for the evaluation of classifier performance. We performed experiments on three different n-gram sizes, i.e.: 4, 5, 6. Results have shown that extraction of common feature approach has produced better results than others. We achieved an overall accuracy of 90.5 % with an n-gram size of 6 from the J48 classifier. The maximum area under ROC achieved was 83.3 % with Random Forest.

  • 27.
    Hameed, Faysal
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för för interaktion och systemdesign.
    Ejaz, Mohammad
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för för interaktion och systemdesign.
    Model for conflict resolution in aspects within Aspect Oriented Requirement engineering2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Krav engineering är den viktigaste fasen inom mjukvaruutveckling faser eftersom det är användas för utvinning av krav från kunder som används av de följande faserna för utformning och genomförandet av systemet. På grund av dess betydelse, denna avhandling fokuserar på sikt aspekt orienterade krav på teknik, som är den första fasen i aspekt Orienten mjukvaran utveckling används för identifiering och representation krav som samlats in i form av oro. Förutom det övergripande förklaring av aspekt oriented Kravet tekniska fasen, detalj uppmärksamhet ges till en specifik verksamhet inom AORE fasen kallas konfliktlösning. Flera metoder som föreslås för konfliktlösning mellan aspekter diskuteras tillsammans med ett försök att ge en ny idé i form av en utvidgning av redan föreslagna modellen för konflikt resolution. Behovet av förlängning av redan föreslagna modellen är motiverad av att använda en fallstudie som appliceras på båda modellerna dvs i den ursprungliga modellen och om den utvidgade modell för att jämföra resultat.

  • 28.
    Haque, Md. Emdadul
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Design of a Self-sufficient Micro-Grid with Renewable Energy Production.2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In power development technology there are pioneering various μ-grid concepts, that integrating multiple distributed power generation sources into a small network serving some or all of the energy needs of participating users can provide benefits including reduced energy costs, increased overall energy efficiency and improved environmental performance and local electric system reliability. In the fast progression of technology the electric vehicles, electric construction equipment and machinery such as- road building or quarries would greatly benefited from electrification and the by this revolutions, they able defending the environment from detrimental effect and potential energy (and local emission) reduction is sufficient. These types of sites are often remotely located and it is much costly to meet the high voltage utility grid or distribution grid, which are normally far-off from the sites. Hence, it would be advantageous to be able to set up such sites without having to build long and expensive connections to high voltage transmission and distribution grids. In this project we have design and proposed a self-sufficient smart DC micro-grid providing renewable energy resources to supply electric machinery is designed. This grid is capable of meeting energy as well as peak power demands of machine site while offering the possibility to fully rely on locally produced renewable energy. In this project we have included price and performance forecasting for solar and wind energy, charger, grid energy storage system and micro-grid power electronics. Therefore, with this design it is capable to provide efficient power supply to the site and can meet the demand at peak loads. Grid modeling and simulating results (including loads, storage and energy production) are done by MATLAB.

  • 29.
    Hoang, Le Nam
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    On The Performance Of Two-Way Amplify-And-Forward Relay Networks2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The new paradigm of cooperative communications is a promising resolution to carry out MIMO technique. In this thesis work, we study the performance of cooperative relay networks in which the transmission from a source to a destination is assisted by one or several relaying nodes employing amplify-and-forward (AF) and decode- and-forward (DF) protocols. The performance of two-way (or bi-directional) AF relay networks, which are proposed to avoid the pre-log factor 1 2 of spectral efficiency, is latter investigated. Specifically, the exact closed-form expressions for symbol error rate (SER), outage probability, and average sum-rate of bi-directional AF relay systems in independent but not identically distributed (i.n.i.d.) Rayleigh fading channels are derived. Our analyses are verified by comparing with the results from Monte-Carlo simulations.

  • 30.
    Hua, Xiaoben
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Yang, Yuxia
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    A Fusion Model For Enhancement of Range Images2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this thesis, we would like to present a new way to enhance the “depth map” image which is called as the fusion of depth images. The goal of our thesis is to try to enhance the “depth images” through a fusion of different classification methods. For that, we will use three similar but different methodologies, the Graph-Cut, Super-Pixel and Principal Component Analysis algorithms to solve the enhancement and output of our result. After that, we will compare the effect of the enhancement of our result with the original depth images. This result indicates the effectiveness of our methodology.

  • 31.
    Husain, Syed Farzad
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Evaluation of Methods for 3D Environment Reconstruction with Respect to Navigation and Manipulation Tasks for Mobile Robots2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Fältet av 3-D-miljö återuppbyggnaden har varit föremål för olika forskningsinsatser under senare år. De ansökningar om mobila robotar är många. Först för navigering uppgifter (särskilt Slam), uppfattningen av 3-D-hinder har många fördelar jämfört navigering i 2-D-kartor, som det vanligtvis görs. Objekt som finns hänger över marken kan erkännas och dessutom robotarna vinna mycket mer information om dess verksamhet området vad som gör lokalisering lättare. För det andra, när det gäller tele-drift av robotar, hjälper en visualisering av miljön i tre dimensioner tele-aktör som utför uppgifter. Därför är en konsekvent, dynamiskt uppdaterade miljö modell avgörande. Tredje kan för mobila manipulation i en dynamisk miljö, en on-line hinder upptäcka och undvika kollisioner förverkligas, om miljön är känd. Under senare forskning, till 3-D-miljö återuppbyggnaden olika strategier har utvecklats. Två av de mest lovande metoderna är FastSLAM och 6-D-Slam. Båda kan bygga täta 3D-miljö kartor on-line. Det första man använder ett partikelfilter som tillämpas på extraherade funktioner i kombination med ett robotsystem modell och en mätning modell för att rekonstruera en karta. Den andra verk på 3-D data punktmoln och rekonstruerar en miljö med hjälp av ICP algoritm. Båda dessa metoder implementeras i GNU C. För det första är FastSLAM genomföras. Det objektorienterade programmering Tekniken används för att bygga upp Partikel-och Extended Kalman filter. För det andra är 6-D SLAM genomförs. Begreppet arv i C används för att göra genomförandet av ICP algoritm så mycket generisk som möjligt. För att testa vårt genomförande en mobil robot som heter Care-O-bot 3 används. Den mobila roboten är utrustad med en färg och en time-of-kamp kamera. Dataset tas som roboten rör sig i olika miljöer och vårt genomförande av FastSLAM och 6-D SLAM används för att rekonstruera kartorna.

  • 32.
    Hussain, Zahid
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Sulaiman, Muhammad
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Sackey, Edward K. E.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Optimal System of Subalgebras and Invariant Solutions for the Black-Scholes Equation2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The main purpose of this thesis is to use modern goal-oriented adaptive methods of Lie group analysis to construct the optimal sys- tem of Black-Scholes equation. We will show in this thesis how to obtain all invariant solutions by constructing what has now become so popular, optimal system of sub-algebras, the main Lie algebra admit- ted by the Black-Scholes equation. First, we obtain the commutator table of already calculated symmetries of the Black-Scholes equation. We then followed with the calculations of transformation of the gen- erators with the Lie algebra L6 which provides one-parameter group of linear transformations for the operators. Here we make use of the method of Lie equations to solve the partial di®erential equations. Next, we consider the construction of optimal systems of the Black- Scholes equation where the method requires a simpli¯cation of a vector to a general form to each of the transformations of the generators. Further, we construct the invariant solutions for each of the op- timal system. This study is motivated by the analysis of Lie groups which is being taken to another level by ALGA here in Blekinge In- stitute Technology, Sweden. We give a practical and in-depth steps and explanation of how to construct the commutator table, the calcu- lation of the transformation of the generators and the construction of the optimal system as well as their invariant solutions. Keywords: Black-Scholes Equation, commutators, commutator table, Lie equa- tions, invariant solution, optimal system, generators, Airy equation, structure constant,

  • 33. Ibragimov, Nail H.
    A practical course in differential equations and mathematical modeling2009Bok (Övrigt vetenskapligt)
    Abstract [en]

    A practical course in differential equations and mathematical modelling is a unique blend of the traditional methods with Lie group analysis enriched by author’s own theoretical developments. The main objective of the book is to develop new mathematical curricula based on symmetry and invariance principles. This approach helps to make courses in differential equations, mathematical modelling, distributions and fundamental solution, etc. easy to follow and interesting for students. The book is based on author’s long-term experience of teaching at Novosibirsk and Moscow Universities in Russia, Collège de France, Georgia Tech and Stanford University in USA, Universities in South Africa, Cyprus, Turkey, and Blekinge Institute of Technology (BTH) in Sweden. The new curriculum prepares the students for solving modern nonlinear problems and attracts essentially more students than the traditional way of teaching mathematics. The book can be used as a main textbook by undergraduate and graduate students and their teachers in applied mathematics, physics and engineering sciences.

  • 34. Ilie, Dragos
    Gnutella Network Traffic: Measurements and Characteristics2006Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Wide availability of computing resources at the edge of the network has lead to the appearance of new services based on peer-to-peer architectures. In a peer-to-peer network nodes have the capability to act both as client and server. They self-organize and cooperate with each other to perform more efficiently operations related to peer discovery, content search and content distribution. The main goal of this thesis is to obtain a better understanding of the network traffic generated by Gnutella peers. Gnutella is a well-known, heavily decentralized file-sharing peer-to-peer network. It is based on open protocol specifications for peer signaling, which enable detailed measurements and analysis down to individual messages. File transfers are performed using HTTP. An 11-days long Gnutella link-layer packet trace collected at BTH is systematically decoded and analyzed. Analysis results include various traffic characteristics and statistical models. The emphasis for the characteristics has been on accuracy and detail, while for the traffic models the emphasis has been on analytical tractability and ease of simulation. To the author's best knowledge this is the first work on Gnutella that presents statistics down to message level. The results show that incoming requests to open a session follow a Poisson distribution. Incoming messages of mixed types can be described by a compound Poisson distribution. Mixture distribution models for message transfer rates include a heavy-tailed component.

  • 35.
    Ishaq, Rizwan
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Adaptive Gain Equalizer and Modulation Frequency Domain for Noise Reduction2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Speech quality during the communication is generally e ected by the surrounding noise and interference. To improve the quality of speech signals and to reduce the amount of disturbing noise, speech enhancement is one of the emerging and most used branches of signal processing. For the reduction of noise from speech signals, methods are continuously developed, one method is the Adaptive Gain Equalizer (AGE) which is a single-channel speech enhancement, method that has the particular focus on enhancement of speech instead suppression of noise. Modulation decomposition of the speech signals brought the idea of a modulation system which is useful for modeling of speech and other signals. The purpose of this thesis is to implement the AGE within modulation system, for the purpose of enhancing speech signal, by reducing noise. The successful implementation of the system has been validated with di erent performance measurements, i.e., Signal to Noise Ratio Improvement(SNRI), Mean Opinion Score(MOS), Spectral Distortion(SD). The system has been checked with male and female speaker and with the noise signals Engine Noise(EN), Factory Noise(FN), Gaussian Noise(GN), Tonal Noise(TN) and Impulse Noise(IN) at 0dB, 5dB, 10dB and -5dB Signal to Noise Ratio(SNR). The system has provided the 10dB SNRI for the TN, and around 6dB SNRI for EN and FN. The system has some compromises on the GN and IN in a sense it gives good sound but low SNRI. MOS has been shown between 4 and 3 for all the test cases.

  • 36.
    ISLAM, MD. JAHERUL
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Performance Analysis of Diversity Techniques for Wireless Communication System2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Different diversity techniques such as Maximal-Ratio Combining (MRC), Equal-Gain Combining (EGC) and Selection Combining (SC) are described and analyzed. Two branches (N=2) diversity systems that are used for pre-detection combining have been investigated and computed. The statistics of carrier to noise ratio (CNR) and carrier to interference ratio (CIR) without diversity assuming Rayleigh fading model have been examined and then measured for diversity systems. The probability of error (p_e) vs CNR and (p_e) versus CIR have also been obtained. The fading dynamic range of the instantaneous CNR and CIR is reduced remarkably when diversity systems are used [1]. For a certain average probability of error, a higher valued average CNR and CIR is in need for non-diversity systems [1]. But a smaller valued of CNR and CIR are compared to diversity systems. The overall conclusion is that maximal-ratio combining (MRC) achieves the best performance improvement compared to other combining methods. Diversity techniques are very useful to improve the performance of high speed wireless channel to transmit data and information. The problems which considered in this thesis are not new but I have tried to organize, prove and analyze in new ways.

  • 37.
    Islam, Md. Samsul
    et al.
    Blekinge Tekniska Högskola, Sektionen för management.
    Zhou, Lin
    Blekinge Tekniska Högskola, Sektionen för management.
    Li, Fei
    Blekinge Tekniska Högskola, Sektionen för management.
    Application of Artificial Intelligence (Artificial Neural Network) to Assess Credit Risk: A Predictive Model For Credit Card Scoring2009Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Credit Decisions are extremely vital for any type of financial institution because it can stimulate huge financial losses generated from defaulters. A number of banks use judgmental decisions, means credit analysts go through every application separately and other banks use credit scoring system or combination of both. Credit scoring system uses many types of statistical models. But recently, professionals started looking for alternative algorithms that can provide better accuracy regarding classification. Neural network can be a suitable alternative. It is apparent from the classification outcomes of this study that neural network gives slightly better results than discriminant analysis and logistic regression. It should be noted that it is not possible to draw a general conclusion that neural network holds better predictive ability than logistic regression and discriminant analysis, because this study covers only one dataset. Moreover, it is comprehensible that a “Bad Accepted” generates much higher costs than a “Good Rejected” and neural network acquires less amount of “Bad Accepted” than discriminant analysis and logistic regression. So, neural network achieves less cost of misclassification for the dataset used in this study. Furthermore, in the final section of this study, an optimization algorithm (Genetic Algorithm) is proposed in order to obtain better classification accuracy through the configurations of the neural network architecture. On the contrary, it is vital to note that the success of any predictive model largely depends on the predictor variables that are selected to use as the model inputs. But it is important to consider some points regarding predictor variables selection, for example, some specific variables are prohibited in some countries, variables all together should provide the highest predictive strength and variables may be judged through statistical analysis etc. This study also covers those concepts about input variables selection standards.

  • 38.
    Islam, Md. Zameari
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Sajjad, G.M. Sabil
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Single Channel Speech Enhancement Using Spectral Subtraction Based on Minimum Statistics2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Speech is an elementary source of human interaction. The quality and intelligibility of speech signals during communication are generally degraded by the surrounding noise. Corrupted speech signals need therefore to be enhanced to improve quality and intelligibility. In the field of speech processing, much effort has been devoted to develop speech enhancement techniques in order to restore the speech signal by reducing the amount of disturbing noise. This thesis focuses on a single channel speech enhancement technique that performs noise reduction by spectral subtraction based on minimum statistics. Minimum statistics means that the power spectrum of the non-stationary noise signal is estimated by finding the minimum values of a smoothed power spectrum of the noisy speech signal and, thus, circumvents the speech activity detection problem. The performance of the spectral subtraction method is evaluated using single channel speech data and for a wide range of noise types with various noise levels. This evaluation is used in order to find optimum method parameter values, thereby improving this algorithm to make it more appropriate for speech communication purposes. The system is implemented in MATLAB and validated by considering different performance measure and for different Signal to Noise Ratio Improvement (SNRI) and Spectral Distortion (SD). The SNRI and SD were calculated for different filter bank settings such as different number of subbands and for different decimation and interpolation ratios. The method provides efficient speech enhancement in terms of SNRI and SD performance measures.

  • 39.
    Islam, Muhammad Adeel
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Shah, Khan Ahmad
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Performance analysis of dual hop cellular networks2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Explosive growth in wireless technology caused by development in digital and RF circuit fabrications put some serious challenges on wireless system designers and link budget planning. Low transmit power, system coverage and capacity, high data rates, spatial diversity and quality of services (QOS) are the key factors in future wireless communication system that made it attractive. Dual-hop relaying is the promising underlying technique for future wireless communication to address such dilemmas. Based on dual-hop relaying this thesis addresses two scenarios. In the first case the system model employs dual-hop amplify and forward (AF) multiple input multiple output (MIMO) relay channels with transmit and receive antenna selection over independent Rayleigh fading channels where source and destination contain multiple antennas and communicate with each other with help of single antenna relay. It is assumed that the source and destination has perfect knowledge of channel state information (CSI). Our analysis shows that full spatial diversity order can be achieved with minimum number of antennas at source and destination i.e. min{N_s N_d }. In the second case the performance analysis of dual-hop amplify and forward (AF) multiple relay cooperative diversity network with best relay selection schemes over Rayleigh fading channels is investigated where the source and destination communicate with each other through direct and indirect links. Only the performance of best relay is investigated which participates in the transmission alone. The relay node that achieves highest SNR at the destination is selected as a best relay. Once again our analysis shows that full diversity order can be achieved with single relay with fewer resources compare to the regular cooperative diversity system.

  • 40.
    Jacobsson, Mattias
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Bitwise relations between n and φ(n): A novel approach at prime number factorization2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Cryptography plays a crucial role in today’s society. Given the influence, cryptographic algorithms need to be trustworthy. Cryptographic algorithms such as RSA relies on the problem of prime number factorization to provide its confidentiality. Hence finding a way to make it computationally feasible to find the prime factors of any integer would break RSA’s confidentiality.

    The approach presented in this thesis explores the possibility of trying to construct φ(n) from n. This enables factorization of n into its two prime numbers p and q through the method presented in the original RSA paper. The construction of φ(n) from n is achieved by analyzing bitwise relations between the two.

    While there are some limitations on p and q this thesis can in favorable circumstances construct about half of the bits in φ(n) from n. Moreover, based on the research a conjecture has been proposed which outlines further characteristics between n and φ(n).

  • 41. Jena, Ajit K.
    et al.
    Popescu, Adrian
    Nilsson, Arne A.
    Modeling and Evaluation of Internet Applications2002Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Det handlar om trafik mättningar, analys samt modellering av några av Internets applikationer (SMTP, HTTP, FTP).

  • 42.
    Kaowichakorn, Peerachai
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Probabilistic Analysis of Quality of Service2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Current complex service systems are usually comprised of many other components which are often external services performing particular tasks. The quality of service (QoS) attributes such as availability, cost, response time are essential to determine usability and eciency of such system. Obviously, the QoS of such compound system is dependent on the QoS of its components. However, the QoS of each component is naturally unstable and di erent each time it is called due to many factors like network bandwidth, workload, hardware resource, etc. This will consequently make the QoS of the whole system be unstable. This uncertainty can be described and represented with probability distributions. This thesis presents an approach to calculate the QoS of the system when the probability distributions of QoS of each component are provided by service provider or derived from historical data, along with the structure of their compositions. In addition, an analyzer tool is implemented in order to predict the QoS of the given compositions and probability distributions following the proposed approach. The output of the analyzer can be used to predict the behavior of the system to be implemented and to make decisions based on the expected performance. The experimental evaluation shows that the estimation is reliable with a minimal and acceptable error measurement.

  • 43.
    Karim, Ehsanul
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Madani, Sri Phani Venkata Siva Krishna
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Yun, Feng
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Fuzzy Clustering Analysis2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The Objective of this thesis is to talk about the usage of Fuzzy Logic in pattern recognition. There are different fuzzy approaches to recognize the pattern and the structure in data. The fuzzy approach that we choose to process the data is completely depends on the type of data. Pattern reorganization as we know involves various mathematical transforms so as to render the pattern or structure with the desired properties such as the identification of a probabilistic model which provides the explaination of the process generating the data clarity seen and so on and so forth. With this basic school of thought we plunge into the world of Fuzzy Logic for the process of pattern recognition. Fuzzy Logic like any other mathematical field has its own set of principles, types, representations, usage so on and so forth. Hence our job primarily would focus to venture the ways in which Fuzzy Logic is applied to pattern recognition and knowledge of the results. That is what will be said in topics to follow. Pattern recognition is the collection of all approaches that understand, represent and process the data as segments and features by using fuzzy sets. The representation and processing depend on the selected fuzzy technique and on the problem to be solved. In the broadest sense, pattern recognition is any form of information processing for which both the input and output are different kind of data, medical records, aerial photos, market trends, library catalogs, galactic positions, fingerprints, psychological profiles, cash flows, chemical constituents, demographic features, stock options, military decisions.. Most pattern recognition techniques involve treating the data as a variable and applying standard processing techniques to it.

  • 44.
    Khan, Fahim
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Mazarati, Pierre Celestin
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Khan, Nasir
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Effect of Primary Network on Performance of Spectrum Sharing System over Nakagami-m Fading Channel2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    During the last few years, we have witnessed that radio spectrum is becoming a valuable and scarce resource due to the increasing demand of multimedia services. However, recent research has shown that most of the available radio spectrum is not used effectively and is wasted. So, to utilize the radio spectrum effectively, a new technology has been introduced known as “Cognitive Radio”. In cognitive radio, a secondary user (SU) uses the vacant holes in licensed spectrum when it is not occupied by a primary user (PU) without causing interference to the PU transmission. Accessing vacant holes in the licensed user spectrum without causing interference to the PU is a complicated task. Therefore, alternative spectrum sharing techniques have gained popularity. Using these techniques, an SU can share the licensed spectrum with a PU at the same time without causing interference to the PU transmission. As a result, a secondary user should have an optimal power allocation policy in order to get a high transmission rate while still keeping the interference caused to the primary user below a threshold value. Under limited spectrum conditions, spectrum sharing relay networks have gained much popularity by providing reliability over direct transmission. In this thesis, we investigate an amplify-and-forward (AF) relay network performance in a spectrum sharing environment. Here, we consider the impact of the primary transmitter on the spectrum sharing system in the presence of a Nakagami-m fading channel, where the fading parameter m (m is an integer) can be used to deal with a variety of channel scenarios.

  • 45.
    Khan, Khalid
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    The Evaluation of Well-known Effort Estimation Models based on Predictive Accuracy Indicators2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Accurate and reliable effort estimation is still one of the most challenging processes in software engineering. There have been numbers of attempts to develop cost estimation models. However, the evaluation of model accuracy and reliability of those models have gained interest in the last decade. A model can be finely tuned according to specific data, but the issue remains there is the selection of the most appropriate model. A model predictive accuracy is determined by the difference of the various accuracy measures. The one with minimum relative error is considered to be the best fit. The model predictive accuracy is needed to be statistically significant in order to be the best fit. This practice evolved into model evaluation. Models predictive accuracy indicators need to be statistically tested before taking a decision to use a model for estimation. The aim of this thesis is to statistically evaluate well known effort estimation models according to their predictive accuracy indicators using two new approaches; bootstrap confidence intervals and permutation tests. In this thesis, the significance of the difference between various accuracy indicators were empirically tested on the projects obtained from the International Software Benchmarking Standard Group (ISBSG) data set. We selected projects of Un-Adjusted Function Points (UFP) of quality A. Then, the techniques; Analysis Of Variance ANOVA and regression to form Least Square (LS) set and Estimation by Analogy (EbA) set were used. Step wise ANOVA was used to form parametric model. K-NN algorithm was employed in order to obtain analogue projects for effort estimation use in EbA. It was found that the estimation reliability increased with the pre-processing of the data statistically, moreover the significance of the accuracy indicators were not only tested statistically but also with the help of more complex inferential statistical methods. The decision of selecting non-parametric methodology (EbA) for generating project estimates in not by chance but statistically proved.

  • 46.
    khan, Maqsood Muhammad
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    khan, Muhammad Saad
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    INVESTIGATION OF HANDOVERS IN 3G UMTS TRAFFIC CLASSES2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The Universal Mobile Telecommunication systems are one of the emerging cellular phone technologies which are known as the 3G systems. It support the high speed data transfer, speech, web browsing, email, video telephony, multimedia and the audio streaming. These services are divided in to the classes depending upon the QoS requirements. With the development of these cellular networks, a major problem came up; it was the call handover from one cell to the other cell during an ongoing session without dropping the connection with the base station. A lot of techniques were developed and used to cope with this major issue. The user’s movement is a dynamic process considering its location. This means that the mobile users can change its way any time with any speed, so there should be a mechanism and a way that the network should be aware of this process. For this purpose different types of handovers techniques are used which include soft, hard and softer handovers. The thesis work is about the investigation of different handovers in the 3G UMTS network which is the vital issue to the network to maintain the user’s connection during in the ongoing session with the user’s movement. The investigation is based on the UMTS QoS traffic classes. For this purpose the soft and the hard handovers techniques are analyzed in different scenarios implemented in the OPNET Modeler. To know and understand about the handover process between the Node B and the user equipment different statistics are calculated.

  • 47.
    Khan, Yawar Saeed
    Blekinge Tekniska Högskola, Sektionen för management.
    STRATEGIES OF HIGHER EDUCATION IN PAKISTAN BASED ON ENDOGENOUS GROWTH2009Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This paper investigates the possible opportunities for Higher Education in Pakistan towards gaining a competitive advantage in the international community, the link between Human capital development and GDP growth in Pakistan and finally compares the HE policies in Pakistan and the EU. We look at empirical evidence and statistical data to investigate how endogenous growth affects the GDP per capita with the case study of Pakistan. The empirical studies show that employing human capital variable in the endogenous production function does not have favorable results on the economic growth output. This leads us to believe that the measuring criterion for Human Capital has to be re-evaluated as there are several factors that affect the educational systems in different parts of the world See Barro (2001), Qaisar (2007) and De la Fuente and Doménech (2002). Hence the definition of Human Capital can vary from region to region in order to get accurate results from the endogenous production function. We performed Pearsons Correlation function on 7 years data of GDP growth, GDP per capita GDP PPP compared with various variables including higher education enrollment rates and labor force in Pakistan. The results show little or no correlation is all experiments which further validate empirical research by Qaisar Abbas. These results are confirming the theory that the Higher Education growth cannot be simply measured in terms of enrollment rates and other variables must be included in the equation. These variables can vary from country to country and a multi ethnic country like Pakistan, measuring these variables is a complex task due to heterogeneous environments. Empirical evidence states that there is a link between human capital and spatial heterogeneity in Pakistan. Unequal opportunities are defeating the advantages of existing supplies of Human Capital. Minimization of educational inequalities enables the poor to receive more benefits of economic growth and that in turn allows the increase in growth rates for the country. A public survey was conducted to investigate general public’s awareness and attitude towards acceptance of Higher Education as a key towards quality of Life and opportunities in Higher Education for a common man in Pakistan. Overall 280 respondents from across Pakistan were engaged. Public survey results show that there is a strong sense of awareness in the general public about higher education being the Key for economic revival in Pakistan. Despite being motivated for educational growth there are various elements that are unattractive for public to pursue a higher degree in Pakistan. We take of look at the survey response towards acceptance of a Pakistani degree against a foreign degree and find that education institutions of Pakistan are majorly unattractive for our prospective future Human Capital supplies. In light of these findings and research studies, we identify a few areas in which the education institutes can impact their internal and external environments to meet the challenges posed in front of them. In the second leg of this dissertation, we perform an analytical review of the background and present status of EU Higher Education policies in contrast to Pakistani Higher Education policies. This dissertation reveals a sharp contrast between the history, plans and implementation of HE Policies in the EU and Pakistan. In the EU, dynamic policy making in the light of the intergovernmental Bologna Process and the Lisbon Strategy is evident how HE has evolved in the EU and provided a roadmap to Lisbon/Bologna declarations [2]. In Pakistan, we can only witness some enthusiastic plans, but lack of implementation force backed with unrealistic economic forecasts which ultimately played a major role in policy failure [3][4]. A detailed analysis and comparison is performed between EU and Pakistan in order to identify benchmarks for Pakistan. We find there are a need of exchange programs at all levels in Pakistan in order to establish a knowledge based community which in turn can be expanded in collaboration wi th other communities and possibly with EU in the form of Bologna process. In the end of the dissertation we conclude that the existing theory of human capital growth has strong relevance in the field of higher education as indicated by our experiments and empirical evidence from Qaisar, Jamal and Hasan. The survey results support the fact that there economic growth is deeply severed due to insufficient supplies of Human capital, the studies and survey results support that fact that un-equal opportunities and lack of financial aid for students is defeating our cause to utilize our demographic dividend or working age group of Human Capital before we enter 2050 and become one of biggest populated nations in the world. Empirical studies tell us that at least 40% of development in East Asian countries can be attributed towards their Human Capital (Demographic dividend)[1]. Pakistan has to capitalize on her Human Capital stock in order to translate this opportunity of a demographic dividend into global economic power. We briefly look into the spatial heterogeneity aspect of human capital growth and knowledge spillovers as possible solution to minimize the silos culture within regions. This dissertation is a non-technical review of Endogenous Growth theories, its application across the countries and in Pakistan. We conclude this dissertation by suggesting some changes in the internal and external environments of higher education institutes and higher education policy re-evaluation in Pakistan. We have identified certain areas of improvement which the Government of Pakistan should consider.

  • 48.
    Lymar, Henning
    Blekinge Tekniska Högskola, Sektionen för planering och mediedesign.
    "You can cut sync, you can´t cut feel" Ett djupdyk in i trampets värld2011Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    I dagens filmbransch blir arbetet med ljud i film allt mer viktigt då publiken inte bara förväntar sig en visuell effekt utan även en helhetsupplevelse. För att filmen skall kunna förmedla rätt känsla till publiken, gäller det att det visuella, musiken och ljudet fungerar så optimalt som möjligt. Det är viktigt att ljudet hjälper filmen att få fram den känslan som regissören vill förmedla. För att ljudet till en film skall kunna hjälpa regissören att förmedla ett budskap eller känsla är det viktigt att arbetet med ljudet också får ta plats i en filmproduktion. Det här arbetet är en skildring mellan arbetet med tramp på ljudföretaget Europa Foley och boken The foley grail. Arbetet beskriver hur processen med tramp till en filmproduktion på Europa Foley kan gå till och vad som skiljer sig med trampet som beskrivs i The foley grail. De största skillnaderna är hur studion är uppbyggd och hur teamet jobbar med trampet till en filmproduktion. Dessutom tar reflektionen upp ett liknande fenomen som jag har upplevt under mitt arbete på Europa Foley och som även författaren Ament beskriver i The foley grail.

  • 49.
    Malmquist, Daniel
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    A probabilistic pricing model for a company's projects2012Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Företagets prissättning påverkas ofta till stor del av estimeringen av konkurrenters projektkostnader, vilket också är huvudområdet i detta examensarbete. Syftet är att utveckla en prissättningsmodell som hanterar osäkerheter, då detta är ett stort problem i rådande prissättningsprocess. En förstudie har utförts, följt av en modellimplementation. En analys av modellen gjordes sedan, innan slutsatser drogs. Projektkostnadsestimering främst, men även sannolikhetsfunktioner och prissättning som ett allmänt koncept, undersöktes i den i huvudsak litterära förstudien. Två lämpliga metoder för projektkostnadsestimering identifierades; Monte Carlo-simulering och Hierarchy Probability Cost Analysis. Dessa ledde till en teoretisk modell för projektkostnadsestimering. En modell implementerades i Matlab. Den behandlar projektkostnadsestimering, men inga andra prissättningsaspekter. Modellen utvecklades baserat på den teoretiska i möjlig utsträckning. Projektkostnader bröts ner i delkostnader som estimerades för konkurrenterna. Dessa ingick i en Monte Carlo-simulering. Konkurrenters projektkostnader estimerades med hjälp av denna teknik. Att analysera modellens noggrannhet var svårt. Den skiljer sig från den teoretiska beträffande hur sannolikhetsfunktioner och korrelationer estimeras. Dessa problem beror på projekt med skiftande karaktärsdrag samt begränsad data och tid. Ett solitt ramverk har dock skapats. Förbättringsmöjligheter finns, t.ex. noggrannare estimat och en modell som behandlar andra prissättningsaspekter. Det huvudsakliga hotet är att ingen underhåller modellen. Hur som helst är estimat inte mer än estimat. Modellen ska därför ses som ett hjälpverktyg, inte ett facit.

  • 50.
    Manchu, Sreenivasarao
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Parameter Identification for Mechanical Joints2006Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    All but the simplest physical systems contains mechanical joints. The behavior of these joints is sometimes the dominant factor in over all system behavior. The potential for occurence of microslip and macroslip normally makes the behavior of joints non-linear. Accurate modeling of joints requires a non-linear ramework. As clamping pressures are typically random ad variable, the behavior of the joints becomes random. Joint geometries are random along with other unknowns of the joints. Two different methods for measuring the energy dissipation are explained. In the experimental method, the energy dissipation of a non-linear joint is calculated from the slope of the envelope of the time response of acceleration. The simulation work is carried out by considering a smooth hysteresis model with the help of Matlab programming. Finally, the parameters are extracted for a specific non-linear system by comparing analytical and experimental results.

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