Ändra sökning
Avgränsa sökresultatet
7891011 451 - 500 av 527
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 451.
    sajiduet84@gmail.com, Sajid Mahmood /
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    mujeeb.abdullah@gmail.com, Mujeeb Abdullah /
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Priority Queuing Based Spectrum sensing Methodology in Cognitive Radio Network2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Radio spectrum is becoming scarce resource due to increase in the usage of wireless communication devices. However studies have revealed that most of the allotted spectrum is not used effectively. Given the demand for more bandwidth and the amount of underutilized spectrum, DSA (Dynamic Spectrum Access) networks employing cognitive radios are a solution that can revolutionize the telecommunications industry, significantly changing the way we use spectrum resources, and design wireless systems and services. Cognitive radio has improve the spectral efficiency of licensed radio frequency bands by accessing unused part of the band opportunistically without interfering with a license primary user PU. In this thesis we investigate the effects on the quality of service (QoS) performance of spectrum management techniques for the connection-based channel usage behavior for Secondary user (SU). This study also consider other factors such as spectrum sensing time, spectrum handoff and generally distributed service time and channel contention for different SUs. The preemptive resume priority M/G/1 queuing theory is used to characterize the above mentioned effects. The proposed structure of the model can integrate various system parameters such spectrum sensing, spectrum decision, spectrum sharing and spectrum handoff.

  • 452.
    Sandgren, Rickard
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknokultur, humaniora och samhällsbyggnad.
    Lundström, Harry
    Blekinge Tekniska Högskola, Sektionen för teknokultur, humaniora och samhällsbyggnad.
    Spelproduktion för 2d miljö2008Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Vi började vårt projekt med grunderna till verktyg för att utveckla spel i 2d. Dessa ämnade vi färdigställa under projektet och med dem utveckla en speldemo. Eftersom vi hade gemensamma visioner om spelutveckling så bestämde vi oss för att samarbeta, och fokusera på våra respektive områden. Med att utveckla egna verktyg ville vi få en större förståelse för de grundläggande mekanismerna av en spelmotor och möjligheten att påverka dessa efter våra specifika behov. Det var också för att hålla koden fri från licensierade komponenter för att i framtiden kunna underlätta distribution.

  • 453. Schenkman, Bo
    Notes on Attitudes to Statistics among Swedish Psychology and Education Science Students: The Effects of Self-perception and Anxiety2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A number of studies have pointed out the resistance to statistics courses and the anxiety it induces among social science students. The attitudes to statistics among psychology and education science students in a new university in Sweden were studied. Seven students were from a higher level course eight were from a course at a second year level. The students were asked voluntarily to respond to a questionnaire. The higher level students were given the questionnaire both before and after the course and they were also interviewed for about one hour each. Although all students experienced anxiety about statistics, some of them had become more positive to statistics after the course. This shows that feelings of interest and anxiety can exist at the same time. The anxiety might often be a result of low self perception of one’s own mathematical abilities. This self-perception must be made more positive. Teaching statistics at the same time to both distance and campus students is not to be recommended. The students expressed a wish for a more continuous teaching of statistics, repetitions, more practical examples and practice in using statistical packages.

  • 454.
    Schwieger, Kay
    et al.
    Iteratec GmbH, GER.
    Wagner, Stefan
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Part III, Free Actions of Compact Quantum Groups on C*-Algebras2017Ingår i: SIGMA. Symmetry, Integrability and Geometry, ISSN 1815-0659, E-ISSN 1815-0659, Vol. 13, artikel-id 62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study and classify free actions of compact quantum groups on unital C*-algebras in terms of generalized factor systems. Moreover, we use these factor systems to show that all finite coverings of irrational rotation C*-algebras are cleft.

  • 455.
    SEKHAR, MADHU KIRAN . EDURU RAJA CHANDRA
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    THOTA, PARTHA SARADHI .
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    CONTROL OF BUCK CONVERTER BY POLYNOMIAL, PID AND PD CONTROLLERS.2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    As per the results point of view, the polynomial performed well than PID and PD controllers. The simulations show that the polynomial controller reaches the reference voltage very well, were the PID and PD result does not differ very much while meeting with the required reference voltage. Thus we conclude that the Polynomial controller design and results were better than the PID and PD Controllers. If we compare both the second order [4] and third order controller methods, The second order controllers are easy in design and gives better responses than third order polynomial PID and PD controllers.

  • 456.
    Seyrafi, Aylar
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Developing Real Time Automatic Step Detection in the three dimensional Accelerometer Signal implemented on a Microcontroller System2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Parkinson’s disease is associated with reduced coordination between respiration and locomotion. For the neurological rehabilitation research, it requires a long-time monitoring system, which enables the online analysis of the patient’s vegetative locomotor coordination. In this work a real time step detector using three-dimensional accelerometer signal for the patients with Parkinson‘s disease is developed. This step detector is a complement for a recently developed system included of intelligent, wirelessly communicating sensors. The system helps to focus on the scientific questions whether this coordination may serve as a measure for the rehabilitation progress of PD patients.

  • 457.
    Shahzad, Hamid
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Botchu, Jaishankar
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Applying OSTBC in Cooperative Cognitive Radio Networks2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this report, we introduce cooperative spectrum sensing using orthogonal space time block coding (OSTBC) in order to achieve cooperative diversity in the cognitive radios (CRs) network. Transmit diversity or gain is achieved by introducing more than one antenna on the transmitter and receiver side, but in small electronic mobile devices it looks impractical. The signals received from the primary users (PUs) are amplified by the cognitive relays and further forwarded to the cognitive controller where decisions are made on the basis of the information collected from each cognitive relay. The cooperative relaying protocol used here in cognitive relays is based on an amplifying-forward (AF) scheme. Alamouti scheme in OSTBC has been proposed to achieve better detection performance in CR network. The energy detector performance is analyzed over an independent Rayleigh fading channel. In CR network the secondary user (SU) shares PU's frequency band if it fi nds PU is not in its vicinity. The SU starts using the licensed band and leaves the band as soon as it finds the PU is present or going to use the same band. The detection of the spectrum holes by CRs has to be more agile and intelligent. The main objective of the CRs network is to use the free holes without causing any interference to the PUs. The energy detection technique is simple and outperforms other sensing techniques in cooperative cognitive radio networks. The energy detector collects information from different users, compares it with a certain prede fined threshold () value and then makes a fi nal decision. Detection and false alarm probabilities are derived and manipulated using OSTBC on PU and SU through AF protocol in cooperative communication. The performance of the system is analyzed with single and multiple relays and with and without direct path between the PUs and SUs. Maximum ratio (MRC) and selection combining (SC) schemes are used in energy detector and the results are compared with and without direct link between PU and SU. The analysis is performed by placing the relay close to the PUs. Our results are processed and validated by computer simulation.

  • 458.
    Shinwary, Ashfaq Ahmad
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Mapping of User Quality-of-Experience to Application Perceived Performance for Web Application.2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Web browsing posses a major share among the activities on the Internet. Heavy usage of web browsing makes the Web Quality of Experience (QoE) one of the critical factor in deciding the overall success of network services. Amongst others, Web QoE can be effected by the delays in network that can result in higher application download times. In this thesis work, an effort has been made to map applications level download times to Quality of Experience. A subjective analysis on how the user takes into account the domain of web browsing has been carried out. For this purpose a testbed was developed at Blekinge Institute of Technology on which different users were tested. Specific sequences of delays were introduced on the network which resulted in desired application download times. Regression analysis was performed and a mapping between user QoE and application download times was carried out. Based on the results conclusions were made which are presented in this thesis report.

  • 459. Shoham, Aviv
    et al.
    Pesämaa, Ossi
    Blekinge Tekniska Högskola, Sektionen för management.
    Gadget Loving: A Test of an Integrative Model2013Ingår i: Psychology & Marketing, ISSN 0742-6046, E-ISSN 1520-6793, Vol. 30, nr 3, s. 29-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Following the seminal work of Bruner and Kumar (2007) on gadget loving, this paper views gadget loving as the attachment individuals have toward advanced electronic items and how such an attachment relates to actual use (i.e., actual gadgets ownership). It extends existing research in two important ways. First, it provides a retest of the reliability and validity of the gadget-loving scale in two new countries (Israel and Sweden), thus adding to the generalizability of the scale across cultures. Second, it develops and tests an integrative model that includes gadget loving as a central construct as well as several antecedents and consequences proposed as important topics for future research in the extant literature. The results show that inherent novelty seeking, technological innovativeness, and technical curiosity predict the gadget-loving trait, which in turn affects technological opinion leadership and gadget ownership. These findings have theoretical and practical implications.

  • 460.
    Siddique, Muhammad
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Fuzzy decision making using max-min and MMR methods2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Fuzzy logic is based on the theory of fuzzy sets, where an object’s membership of a set is gradual rather than just member or not a member. Fuzzy logic uses the whole interval of real numbers between zero (False) and one (True) to develop a logic as a basis for rules of inference. Particularly the fuzzified version of the modus ponens rule of inference enables computers to make decisions using fuzzy reasoning rather than exact. We study decision making problem under uncertainty. we analyze Max-Min method and Minimization of regret method originally developed by Savage and further developed by Yager. We generalize The MMR method by creating the parameterized family of minimum regret methods by using the ordered weighted averaging OWA operators.

  • 461.
    Silase, Geletu Biruk
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Modeling the Behavior of an Electronically Switchable Directional Antenna for Wireless Sensor Networks2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Reducing power consumption is among the top concerns in Wireless Sensor Networks, as the lifetime of a Wireless Sensor Network depends on its power consumption. Directional antennas help achieve this goal contrary to the commonly used omnidirectional antennas that radiate electromagnetic power equally in all directions, by concentrating the radiated electromagnetic power only in particular directions. This enables increased communication range at no additional energy cost and reduces contention on the wireless medium. The SPIDA (SICS Parasitic Interference Directional Antenna) prototype is one of the few real-world prototypes of electronically switchable directional antennas for Wireless Sensor Networks. However, building several prototypes of SPIDA and conducting real-world experiments using them may be expensive and impractical. Modeling SPIDA based on real-world experiments avoids the expenses incurred by enabling simulation of large networks equipped with SPIDA. Such a model would then allow researchers to develop new algorithms and protocols that take advantage of the provided directional communication on existing Wireless Sensor Network simulators. In this thesis, a model of SPIDA for Wireless Sensor Networks is built based on thoroughly designed real-world experiments. The thesis builds a probabilistic model that accounts for variations in measurements, imperfections in the prototype construction, and fluctuations in experimental settings that affect the values of the measured metrics. The model can be integrated into existing Wireless Sensor Network simulators to foster the research of new algorithms and protocols that take advantage of directional communication. The model returns the values of signal strength and packet reception rate from a node equipped with SPIDA at a certain point in space given the two-dimensional distance coordinates of the point and the configuration of SPIDA as inputs.

  • 462.
    Sinaian, Pouya
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Application of Ibragimov's method and Noether's theorem for constructing conservation laws of the linear elasticity model2014Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this thesis, conservation laws of the Lame equation describing linear elasticity have been constructed. This has been done by the implementation of two theorems for constructing conservation laws: the new theorem suggested by N H.Ibragimov, and the classical theorem presented by E.Noether. As a result one can see that the Ibragimov method provides more conservation laws than the Noether theorem, which may suggest the better efficiency of the Ibragimov method.

  • 463.
    Sobolewska, Katarzyna-Ewa
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för programvarusystem.
    Web links utility assessment using data mining techniques2006Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This paper is focusing on the data mining solutions for the WWW, specifically how it can be used for the hyperlinks evaluation. We are focusing on the hyperlinks used in the web sites systems and on the problem which consider evaluation of its utility. Since hyperlinks reflect relation to other webpage one can expect that there exist way to verify if users follow desired navigation paths. The Challenge is to use available techniques to discover usage behavior patterns and interpret them. We have evaluated hyperlinks of the selected pages from www.bth.se web site. By using web expert’s help the usefulness of the data mining as the assessment basis was validated. The outcome of the research shows that data mining gives decision support for the changes in the web site navigational structure.

  • 464. Sochor, Jana
    et al.
    Mbiydzenyuy, Gideon
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Larsson, Pia
    Assessing the Benefits of Intelligent Truck Parking2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    The aim of this paper is to identify and provide a discussion about aspects related to benefits of Intelligent Truck Parking (ITP) for Heavy Goods Vehicles (HGVs) and their effects on different stakeholders. Most existing work has narrowly focused on benefits for private cars and does not include the user perspective. In this paper, a review of previous work helps identify benefit areas and stakeholder groups relevant for HGV transport. These benefit areas are then theoretically assessed and compared for different stakeholders. Additionally, interview results of Swedish drivers’ and companies’ perceptions of the ITP service are presented. Comparing results of the interviews with the theoretical assessment indicates that the end users may not perceive ITP as highly beneficial although they theoretically benefit the most. Companies, particularly national haulage companies, expressed a low willingness to pay for the service. The general conclusion is that the ITP service has a better chance of success as part of a package of services rather than as a stand-alone service.

  • 465. Suksern, Supaporn
    et al.
    Meleshko, Sergey
    Ibragimov, Nail H.
    Criteria for fourth-order ordinary differential equations to be linearizable by contact transformations2009Ingår i: Communications in nonlinear science & numerical simulation, ISSN 1007-5704, E-ISSN 1878-7274, Vol. 14, nr 6, s. 2619-2628Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solution of linearization problem of fourth-order ordinary differential equations Via contact transformations is presented in the paper. We show that all fourth-order ordinary differential equations that are linearizable by contact transformations are contained in the class of equations which is at most quadratic in the third-order derivative. We provide the linearization test and describe the procedure for obtaining the linearizing transformations as well as the linearized equation. Moreover, we obtain the general form of ordinary differential equations of order greater than four linearizable via contact transformations. (C) 2008 Elsevier B.V. All rights reserved.

  • 466.
    Svanberg, Niklas
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Gertsovich, Irina
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Analysis of MIG Welding with Aim on Quality2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Since 1987 Uddcomb Engineering has repaired pulps by their own developed overlay welding method even called Uddcomb method. Currently each welding machine is operated by two persons. To increase Uddcomb Engineering competitiveness the reduced number of operators is desired. An installation of a monitoring system which can aid humans in the welding quality control also helps to improve company’s position. A future goal would be to make this monitoring system automatic without a human operator in the loop. In this thesis, arc voltage, weld current and audio signals were collected and analyzed with aim on finding algorithms to monitor the quality of the welding process. The use of statistics tools is the basis for detecting variations in the voltage and current data, associated with welding process. It has been shown that voltage signal can be used as a part of the welding quality control. The audio signal from welding at low frequencies varies with the speed of the process. The signal can also be incorporated in the monitoring of the process. The use of filters, growing sums and statistics are key elements in the algorithms presented in this report.

  • 467.
    Sörensson, Uno
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Verifiering av forskningsresultat gällande antal lösningar för linjära kongruenssystem2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Verifiering med hjälp av dator av två oberoende formler för beräkning av antalet lösningar för linjära kongruenssystem med två eller tre obekanta.

  • 468.
    Taghavianfar, Mohsen
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    An Investigation on Network Entropy-Gossiping Protocol and Anti-entropy Evaluation2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Gossiping Protocols, are inherently random in behavior.Nonetheless, they are not structure-less. Their asymptotic behavior when implemented in large scales is the matter of focus in this thesis.

  • 469.
    Tahseen, Muhammad Mustafa
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Khan, MatiUllah
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Ullah, Farhan
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Analysis of OSTBC in Cooperative Cognitive Radio Networks using 2-hop DF Relaying Protocol2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    To achieve cooperative diversity in cognitive radio network, Decode and Forward (DF) protocol is implemented at Cognitive Radios (CRs) using Orthogonal Space Time Block Coding (OSTBC). The 2-hop communication between source and destination is completed with the help of Cognitive Relays (CRs) using Multiple Input Multiple Output (MIMO) technology within the network. To achieve spatial diversity and good code rate Alamouti 2×2 STBC is used for transmission. CR is using the decoding (Decode and Forward (DF)) strategy and without amplifying ability before forwarding data towards destination provide better performance. The main objective of this thesis is to detect Primary User (PU) spectrum availability or non-availability for the use of Secondary Users (SU). The Alamouti STBC encoded data is broadcasted to wireless Rayleigh faded channel through transmitter having two transmitting antennas. The CRs are preferred to place close with PU to detect transmitted signal and because of having decoding capability CRs decode the collected data using Maximum Likelihood (ML) decoding technique then re-encode the decoded data for further transmission towards receiver. The energy of PU signal received at relays is calculated using energy detector used at cognitive controller having authority to make final decision about presence or absence of PU signal within the spectrum by comparing calculated energy of PU received signal with a predefined value. If the calculated signal energy is less than threshold value it is pretended as the absence of PU and in the other case spectrum is assumed as occupied by PU. Decoding PU signal at relays before forwarding towards destination provide better performance in terms of detection probability and decreasing probability of false alarming as the Signal to Noise (SNR) increases. The proposed cooperative spectrum sensing using DF protocol at cognitive relays with Alamouti STBC is implemented and results are validated by MATLAB simulation.

  • 470.
    Talib, Ahmed Abedelhussain
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Optimal system of subalgebras and invariant solutions for a nonlinear wave equation2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This thesis is devoted to use Lie group analysis to obtain all invariant solutions by constructing optimal system of one-dimensional subalgebras of the Lie algebra L5 for a nonlinear wave equation. I will show how the given symmetries ( Eq.2) are admitted by using partial differential equation (Eq.1), In addition to obtain the commutator table by using the same given symmetries. Subsequently, I calculate the transformations of the generators with the Lie algebra L5, which provide the 5-parameter group of linear transformations for the operators. Finally, I construct the invariant solutions for each member of the optimal system.

  • 471.
    Talukder, Satyobroto
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Mathematicle Modelling and Applications of Particle Swarm Optimization2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Optimization is a mathematical technique that concerns the finding of maxima or minima of functions in some feasible region. There is no business or industry which is not involved in solving optimization problems. A variety of optimization techniques compete for the best solution. Particle Swarm Optimization (PSO) is a relatively new, modern, and powerful method of optimization that has been empirically shown to perform well on many of these optimization problems. It is widely used to find the global optimum solution in a complex search space. This thesis aims at providing a review and discussion of the most established results on PSO algorithm as well as exposing the most active research topics that can give initiative for future work and help the practitioner improve better result with little effort. This paper introduces a theoretical idea and detailed explanation of the PSO algorithm, the advantages and disadvantages, the effects and judicious selection of the various parameters. Moreover, this thesis discusses a study of boundary conditions with the invisible wall technique, controlling the convergence behaviors of PSO, discrete-valued problems, multi-objective PSO, and applications of PSO. Finally, this paper presents some kinds of improved versions as well as recent progress in the development of the PSO, and the future research issues are also given.

  • 472.
    Tan, Lujiao
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Takagi-Sugeno and Mamdani Fuzzy Control of a Resort Management System2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    By means of fuzzy set theory as well as Takagi-Sugeno and Mamdani fuzzy controller, this paper presents the investigation of a Resort Management System implemented by a combination of a T-S model and a Mamdani model. It demonstrates the procedure of the specific premise parameters identification and consequence parameters identification performed by regression knowledge in the T-S model, and the process of the fuzzification, the rule base creation and the defuzzification with COG technique in the Mamdani model. Therefore, an aggregation between T-S controller and Mamdani controller applied in the field of management by a novel angle is illustrated, which, as a result, devotes an improved management system that shares great convenience in the control process when combined with mathematics. Moreover, a modification of the conventional Takagi-Sugeno and Mamdani controller is demonstrated in conjunction with fuzzy operations t-norms and OWA by adjusting the -value, which is used in the calculation of final outputs in the T-S model and the computation of rule consequences in the Mamdani model. The algebraic intersection, bounded intersection as well as the -parameter t-norm are the t-norms which are going to be introduced. Besides, we have tested that t-norms generate the same alpha values when the membership degrees meet the boundary with the value of 1 or 0 while OWA can still yield a well-balanced result different from the one computing by minimum operation. Nevertheless both t-norms and OWA are able to shift the alpha-value in a well-adjusted way when the membership degrees lie in the interval [0,1]. A tendency has been shown that alpha-value tends to decrease by means of t-norms and OWA operations and consequently, the final outputs appear to be reduced.

  • 473.
    THUPALLI, NAVEEN KUMAR
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    MICROPHONE ARRAY SYSTEM FOR SPEECH ENHANCEMENT IN LAPTOPS2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Recognition of speech at the receiver end generally gets degraded in distant talking atmospheres of laptops, teleconfereing, video conferences and in hands free telephony, where the quality of speech gets contaminated and severely disturbed because of the additive noises. To make useful and effective, the exact speech signals has to be extracted from the noise signals and the user has to be given the clean speech. In such conditions the convenience of microphone array has been preferred as a means of civilizing the quality of arrested signals. A consequential growth in laptop technology and microphone array processing have made possible to improve intelligibility of speech while communication. So this contention target on reducing the additive noises from the original speech, beside design and use of different algorithms. In this thesis a multi-channel microphone array with its speech enhancement of signals to Wiener Beamformar and Generalized side lobe canceller (GSC) are used for Laptops in a noisy environment. Systems prescribed above were implemented, processed and evaluated on a computer using Mat lab considering SNR, SNRI as the main objective of quality measures. Systems were tested with two speech signals, among which one is Main speech signal and other is considered as Noise along with another random noise, sampling them at 16 KHz .Three Different source originations were taken into consideration with different input SNR’s of 0dB, 5dB, 10dB, 15dB, 20dB, 25dB. Simulation Results showed that Noise is been attenuated to a great extent. But Variations in SNR and SNRI has been observed, because of the different point origination of signals in the respective feilds.Variation in SNR and SNRI is been observed when the distance between the main speech originating point and microphone is too long compared to the noise signals. This states that origination of signals plays a huge role in maintaining the speech quality at the receiver end.

  • 474. Toft, Joachim
    An Embedding Result for some General Symbol Classes in the Weyl Calculus1999Konferensbidrag (Refereegranskat)
    Abstract [en]

    The paper deals with inclusion relations between s(p) and H-s(p). Here s(p) is the set of all a is an element ofJ such that the Weyl operator a(w) (x, D) is a Schatten-von Neumann operator on L-2 to the order p is an element of [1, infinity], and H-s(p) is the Sobolev space of distributions with s derivatives in L-p. At the same time we compute the trace norm for a(w) (x, D), when a is an arbitrary Gauss function.

  • 475. Toft, Joachim
    Continuity Properties for Modulation Spaces, with Applications to Pseudo-differential Calculus-I2004Ingår i: Journal of the Functional Analysis, ISSN 0022-1236 , Vol. 207, nr 2, s. 399-429Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Let M-p,M- q denote the modulation space with parameters p, q is an element of [1, infinity]. If 1/p(1) + 1/p(2) = 1 + 1/p(0) and 1/q(1) + 1/q(2) = 1/q(0), then it is proved that M-p1,M- q1 * M-p2,M- q2 subset of M-p0,M- q0. The result is used to get inclusions between modulation spaces, Besov spaces and Schatten classes in calculus of psido (pseudo-differential operators), and to extend the definition of Toeplitz operators. We also discuss continuity of ambiguity functions and psido in the framework of modulation spaces.

  • 476. Toft, Joachim
    Continuity properties in non-commutative convolution algebras, with applications in pseudo-differential calculus2002Ingår i: Bulletin des Sciences Mathématiques, ISSN 0007-4497, E-ISSN 1952-4773, Vol. 126, nr 2, s. 115-142Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study continuity properties for a family {s(p)} p greater than or equal to 1 of increasing Banach algebras under the twisted convolution, which also satisfies that a is an element of s(p), if and only if the Weyl operator a(w) (x, D) is a Schatten-von Neumann operator of order p on L-2. We discuss inclusion relations between the s(p)-spaces, Besov spaces and Sobolev spaces. We prove also a Young type result on sp for dilated convolution. As an application we prove that f (a) is an element of s(1), when a is an element of s(1) and f is an entire odd function. We finally apply the results on Toeplitz operators and prove that we may extend the definition for such operators. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.

  • 477. Toft, Joachim
    Embeddings for modulation spaces and Besov spaces2001Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Den första delen av uppsatsen berör faltningsegenskaper mellan moduleringsrum och Lebesguerum. Detta tillämpas sedan för att få fram inbäddningsrelationer mellan moduleringsrum och Besovrum.

  • 478. Toft, Joachim
    Modulation spaces and pseudo-differential operators2002Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Modulationsrummen infördes av H. Feichtinger som lämpliga att arbeta inom för att lösa vissa typer av problem som förekommer inom tid/frekvensanalysen. Sedan en tid tillbaka har det även visat sig att dessa är intressanta inom pseudodifferentialkalkylen och försett detta område med nya typer av operatorer som även har mening under mera ruffiga förhållanden. Det som behandlas här är framförallt vissa kontinuitetsaspekter för modulationsrum. Speciellt filtreringar (eller, med matematiska termer, faltningar) för sådana funktioner och vissa inrymningssatser mellan några kända rum och modulationsrum. Vidare behandlas kontinuitet för tvetydighetsfunktionen och Wignerdistributionen, där den sistnämnda medger gemensam tid/frekvens-representation inom signalanalysen. Dessa resultat kan i sin tur tillämpas inom pseudodifferentialkalkylen och på Toeplitzoperatorer.

  • 479. Toft, Joachim
    Modulation spaces of non-standard type and pseudo-differential operators2003Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    I skriften behandlas allmänna kontinuitetsfrågor för viktade modulationsrum. Många av resultaten följer av en karakteriseringsegenskap, vilken möjliggör att man kan överföra problem så att man har att göra med oviktade modulationsrum. I sista delen av arbetet används det hela för att visa vissa kontinuitetsegenskaper inom pseudodifferentialkalkylen.

  • 480. Toft, Joachim
    Positivity Properties for Non-commutative Convolution Algebras with Application in Pseudo-differential Calculus2001Rapport (Övrigt vetenskapligt)
  • 481. Toft, Joachim
    Positivity properties in noncommutative convolution algebras with applications in pseudo-differential calculus2003Ingår i: Bulletin des Sciences Mathématiques, ISSN 0007-4497, E-ISSN 1952-4773, s. 101-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study Y'(+), of all a is an element of D' such that (a *sigma, phi, phi) greater than or equal to 0 for every phi is an element of C-0(infinity), where *phi denotes the twisted convolution. We prove that certain boundedness for a E Y' are completely determined of the behaviour for a at origin, for example that a is an element of Y'(+), and that if a(0) < &INFIN;, then a &ISIN; L-2 &AND; L-&INFIN;. We use the results in order to determine wether positive pseudo-differential operators belong to certain Schatten-casses or not. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.

  • 482. Toft, Joachim
    Regularizations, decompositions and lower bound problems in the Weyl calculus2000Ingår i: Communications in Partial Differential Equations, ISSN 0360-5302, E-ISSN 1532-4133, s. 1201-1234Artikel i tidskrift (Refereegranskat)
  • 483.
    Toft, Joachim
    Blekinge Tekniska Högskola, Institutionen för hälso- och naturvetenskap.
    Some Positivity Properties in the Weyl Calculus1999Rapport (Refereegranskat)
    Abstract [en]

    In this paper we shall deal with some positivity questions arises in the Weyl calculus.

  • 484.
    Toft, Joachim
    Blekinge Tekniska Högskola, Institutionen för hälso- och naturvetenskap.
    Subalgebras to a Wiener type algebra of Pseudo-differential operators2000Rapport (Refereegranskat)
    Abstract [en]

    We study general continuous properties for an increasing family of Banach spaces of classes for pseudo-differential symbols, where the largest symbol space was introduced by J. Sjöstrand 1993. We prove that corresponding pseudo-differential operators are contained in the some certain sets of Schatten-von Neumann operators. We prove also that one obtains Hölder relations from the operator product and the usual multiplication, and that the convolution multiplication give rise to some Young type relations. Some further extensions are also discussed

  • 485. Toft, Joachim
    Subalgebras to a Wiener type algebra of pseudo-differential operators2001Ingår i: Annales de l'Institut Fourier, ISSN 0373-0956, E-ISSN 1777-5310, Vol. 5, nr 5, s. 1347-1383Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study general continuity properties for an increasing family of Banach spaces S-W(P) of classes for pseudo-differential symbols, where S-W(infinity) = S-w was introduced by J. Sjostrand in 1993. We prove that the operators in Op(S-W(P)) are Schattenvon Neumann operators of order p on L-2. We prove also that Op(S-w(p))Op(S-w(r)) subset of Op(S-w(r)) and S-w(p) . S-w(q) subset of S-w(r) provided 1/p+1q = 1/r. If instead 1/p + 1/q = 1+1/r, then S-w(p) w* S-w(q) subset of S-w(r). By modifying the definition of the S-w(p) -spaces, one also obtains symbol classes related to the S(m, g) spaces.

  • 486. Toft, Joachim
    Weighted Modulation Spaces and Pseudo-Differential Operators2003Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    I uppsatsen analyseras viktade modulationsrum. Det visas bl a att många av dessa, däribland de viktigaste, kan erhållas på ett naturligt sätt från standardmodulationsrummen. Dessa egenskaper gör att många problem kan omformuleras så att enbart standardmodulationsrum förekommer. I uppsatsen demonstreras detta på inbäddningsrelationer mellan modulationsrum och Sobolevrum/Besovrum, samt nya kontinuitetsresultat inom pseudodifferentialkalkylen och teorin för Toeplitz operatorer. En del uppmärksamhet riktas även till den tvistade faltningsalgebran, som har nära relationer med Weylkalkylen inom teorin för pseudodifferentialoperatorer. Nyckelord: Modulationsrum, pseudodifferentialoperatorer, Toeplitzoperatorer, inbäddningar, faltningar, spåroperatorer

  • 487.
    Tomalik, Edyta
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Image-based Microscale Particle Velocimetry in Live Cell Microscopy2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Background: Nowadays, one of the medical problem is rolling cell adhesion. Rolling cell adhesion is a complex process that requires the analysis of the challenging environment such as body fluid and is the process responsible for recruiting the cell to specific organs. In order to explore the rolling cell adhesion, mathematical model is proposed. Different image processing methods are created, such as optical flow - Lucas Kanade algorithm, and other type of methods related to mechanical fluid, namely PIV (Particle Image Velocimetry). Aim: The aim of this master thesis is the identification of challenges while using PIV in live cell images and propose the algorithm, which may analyze the rolling cell adhesion problem. Methods: In order to understand properly the rolling cell adhesion problem from biological site, literature review combined with the expert consultation is performed. According to gather information, mathematical model is proposed. Particle Image Velocimetry is explained according to literature review, where at the beginning the expert recommends some books as a primary research. As a result of this research, PIV challenges are identified and generally PIV idea is explained. Then two experiments are performed. The first experiment evaluates detection algorithms and the second one, analyses track algorithm vs. PIV. In order to evaluate the mentioned algorithms, some evaluation method are selected and some criteria are defined. Unfortunately the found methods are not perfect, therefore a new method related to performance evaluation using time series is proposed. Thesis result: The result of this thesis is a proposition of the algorithm, which can be used in the rolling cell adhesion. The algorithm is formed according to the detailed exploration of the rolling cell adhesion and analysis of the selected algorithms related to the image analysis during the theoretical research and experiments.

  • 488. Torkar, Richard
    et al.
    Awan, Nasir Majeed
    Alvi, Adnan Khadem
    Afzal, Wasif
    Predicting Software Test Effort in Iterative Development Using a Dynamic Bayesian Network2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Projects following iterative software development methodologies must still be managed in a way as to maximize quality and minimize costs. However, there are indications that predicting test effort in iterative development is challenging and currently there seem to be no models for test effort prediction. This paper introduces and validates a dynamic Bayesian network for predicting test effort in iterative software devel- opment. The proposed model is validated by the use of data from two industrial projects. The accuracy of the results has been verified through different prediction accuracy measurements and statistical tests. The results from the validation confirm that the model has the ability to predict test effort in iterative projects accurately.

  • 489. Torsti, T
    et al.
    Lindberg, Vanja
    Real-space electronbic-property calculations for nano-scale structure2006Ingår i: Handbook of Theoretical and Computational Nanotechnology, edited by Michael Rieth and Wolfram Schommers, American Scientific Publishers , 2006, s. 771-795Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 490. Törnquist, Johanna
    Dynamic railway traffic management during disturbances: focus on the complexity imposed by deregulation2008Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Att järnvägstransporterna ökar är mycket glädjande, men har aktualiserat kapacitetsproblem och medfört att trafiken har blivit allt känsligare för störningar. En mindre försening av ett enskilt tåg kan få stora följdeffekter på andra tåg. En utmaning är därför att operativt minimera effekterna av störningarna och denna artikel presenterar en experimentell studie där fem olika principer för trafikstyrning utvärderas.

  • 491. Törnquist, Johanna
    Railway traffic disturbance management2006Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    I takt med att järnvägsmarknaden avregleras, användningen av järnvägstransporter ökar och kapacitetsbrister uppstår som medför brister i punktlighet och tillförlitlighet, blir behovet av att kunna hantera störningar och förseningar allt mer aktuellt. Denna doktorsavhandling fokuserar på lösningsmetoder som syftar till att minimera konsekvenserna av de störningar som uppstår i järnvägstrafiken genom effektiv omplanering av tidtabellen. Störningshanteringen och omplaneringen hanteras idag ofta manuellt av tågtrafikledare som har en mycket begränsad tillgång till beslutsstöd. Denna begränsning medför svårigheter för trafikledarna att fatta optimala, hållbara beslut och analysera samt kommunicera konsekvenserna till operatörerna och andra berörda. Inledningsvis gjordes en studie om hur användarna av det svenska järnvägsnätet upplever och påverkas av störningar i trafiken och hur störningarna och dess effekter kommuniceras och hanteras av trafikledningen. Studien visade att användarna anser att informationen om aktuella störningar och dessas effekter som förmedlas av trafikledningen är otillräcklig. Användarna, och då främst operatörerna, behöver tillförlitliga prognoser om hur deras tåg påverkas för att de internt ska kunna hantera avvikelser i syfte att minimera konsekvenserna. I gengäld behöver dock operatörerna informera trafikledningen om sina interna preferenser och planer för att trafikledarna ska kunna fatta goda beslut i linje med operatörernas behov. Förutom användarstudien har även en kartläggning av vilka faktorer som styr trafikflödet gjorts. Kartläggningen visade att det finns en mängd fundamentala restriktioner, såsom att vissa säkerhetsavstånd mellan tågen ska bibehållas, men även ett antal mer mindre restriktiva hänsynstaganden såsom prioritering av vissa tåg vars inverkan är situationsberoende och vars signifikans varierar. I vilken utsträckning dessa hänsynstaganden påverkar trafikflödet och besluten som tas är dock svårt att definiera och mäta. Även strategiska såväl som operativa syften och mål med omplaneringen är svårdefinierade, vilket försvårar en utvärdering av effekten av och kvaliteten på operativa beslut och en jämförelse av olika strategier och riktlinjer. Som ett steg i att råda bot på bristen på beslutstöd för tågtrafikledarna har vi även utvecklat och utvärderat ett antal lösningsmetoder för omplanering av tågtrafiken under störningar. Metoderna baseras på optimeringstekniker och syftar till att ge tågtrafikledarna förslag på lämpliga åtgärder vid omplaneringen. Metodernas tillämpbarhet och prestanda har utvärderats experimentellt för olika typer av störningar baserat på verkliga data för vissa delar av det svenska järnvägsnätet där kapacitetsbrist råder. Resultaten visade att det finns beroenden mellan typ av störningar, deras egenskaper och hur de sprider sig och påverkar möjligheterna att tillräckligt snabbt kunna skapa en tillräckligt bra omplanering. Vi utvärderade även hur val av målfunktion för och syfte med omplaneringen påverkar vilka lösningar som genereras samt hur målstyrningen påverkar de nyckeltal som mäter en lösnings kvalitet. Utvärderingen visade bland annat att en minimering av ackumulerad störning kan leda till att fler tåg blir fördröjda än om omplaneringen istället fokuserar på att minimera den totala förseningen av tåg vid sin slutdestination eller en minimering av den totala kostnaden som kan relateras till störningen och dess spridning. Genom experimentella studier analyserade vi slutligen även effekten av en omplanering som tillämpar endast ett begränsat tidsperspektiv, dvs. vilka effekter som fås på längre sikt om man gör en mer kortsiktig omplanering med endast t ex en timmes framförhållning. Analysen visade att man kan uppnå lösningar som är lämpliga även på längre sikt trots att planeringen görs med avseende på en begränsad tidsperiod. Som komplement till de optimeringsbaserade modellerna och metoderna för omplanering har vi även modellerat omplaneringsprocessen och -problematiken med hjälp av agentteknologi. Fokus var på interaktionen mellan de olika aktörerna i processen och hur deras enskilda mål och beteenden påverkar trafikflödet. Nyckelord: Järnvägstrafik, Transportsystem, Transportation, Operativ planering, Störningshantering, Beslutstödsystem.

  • 492.
    Uddin, Sheikh Fakhar
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Khattak, Ismail Khan
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Spectrum Selection Technique to Satisfy the QoS Requirements in Cognitive Radio Network2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The demand of wireless spectrum is increasing very fast as the field of telecommunication is advancing rapidly. The spectrum was underutilized because of fixed spectrum assignment policy and this valuable spectrum can be utilized efficiently by cognitive radio technology. In this thesis we have studied spectrum selection problems in cognitive radio network. Channel sharing and channel contention problems arise when multiple secondary users tend to select same channel. The thesis work is focused on spectrum selection issue with the aim to minimize the overall system time and to solve the problem of channel contention and channel sharing. The overall system time of secondary connection is an important performance measure to provide quality of service for secondary users in cognitive radio network. We studied two spectrum selection schemes that considerably reduce the overall system time and resolve the problems of channel sharing and channel contention. An analytical model associated with Preemptive Resume Priority (PRP) M/G/1 queuing model has been provided to evaluate the studied spectrum selection scheme. This model also analyzes the effect of multiple handoffs due to arrival of primary users. According to this scheme, the traffic load is distributed among multiple channels to balance the traffic load. Secondary users select the operating channels based on the spectrum selection algorithm. They can intelligently adopt better channel selection scheme by considering traffic statistics and overall transmission time. All simulation scenarios are developed in MATLAB. Based on our result we can conclude that both channel selection schemes considerably reduce the overall transmission time of secondary users in cognitive radio network. The overall transmission time increase with the rise of arrival rate of secondary user. The probability based channel selection scheme perform better with lower arrival rate and sensing based channel selection scheme perform better with higher arrival rate of secondary users. These channel selection schemes help distribute the traffic load of secondary users evenly among multiple channels. Hence, increase the channel utilization and resolve the channel contention problem.

  • 493.
    Vasiljeva, O. A.
    et al.
    Moscow State Univ., RUS.
    Lapshin, E. A.
    Moscow MV Lomonosov State Univ., RUS.
    Rudenko, Oleg
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Projection of the Khokhlov-Zabolotskaya Equation on the Axis of Wave Beam As a Model of Nonlinear Diffraction2017Ingår i: Doklady. Mathematics, ISSN 1064-5624, E-ISSN 1531-8362, Vol. 96, nr 3, s. 646-649Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An equation is obtained that describes the nonlinear diffraction of a focused wave in a half-space starting from the wave source, then through the focus region up to the far zone, where the wave becomes spherically divergent. In contrast to the Khokhlov-Zabolotskaya equation (KZ), which contains two spatial variables, the calculation of the field on the beam axis is reduced to a simpler one-dimensional problem. Integral relations that are useful for numerical calculation are indicated. The profiles of a periodic wave harmonic at the input to the medium are constructed. A comparison with the results of a numerical solution of problems based on KZ is made, which revealed a good accuracy of the approximate model. The passage of a wave through the focus region, accompanied by the formation of shock fronts, diffraction phase shifts and asymmetric distortion of regions of different polarity, is traced.

  • 494.
    VIENJIPURAM, KRISHNA KUMARAN
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    ABDUL, ASMEER BABU
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Improving the Quality of Multicast Networks by Using the OPNET Modeler2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This thesis presents different Internet Protocol (IP) multicasting design models and together with their implementation methods in OPNET Modeler 14.5. The models presented in this report are designed for handling various types of advanced multimedia applications and services when using the multicast communication paradigm. The architectural models presented in this thesis are independent of the routing protocols used as well as of the underlying networking environment. Several exiting challenges related to high bandwidth requirements, low network delay, and jitter are discussed together with these design models, and are simulated using the OPNET Modeler. The emerging demands for new multicast capable applications, for both real-time and non real-time traffic are considered together in this report in order to better evaluate multicast traffic requirements. Efficient routing methods, group management policies, and shortest path algorithms are also discussed in the proposed models. The pros and cons of IP multicasting are described using the Protocol Independent Multicast Sparse Mode (PIM-SM) method, in the highlight of the proposed design models. Several results related to link utilization, end-to-end delay, packet loss, PIM control traffic, Internet Group Management Protocol (IGMP), and network convergence are obtained by using already available statistical methods and modules from OPNET Modeler. Our major contribution with this thesis work relates to components associated with network convergence, routing delay, and processing delay. These components are illustrated in this thesis using various OPNET metrics. Moreover, several issues related to protocol scalability, supportability, performance optimization and efficiency are also presented by using OPNET’s build in reports, i.e., executive flow and survivability analysis reports.

  • 495.
    Vu, Viet Thuy
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Nehru, Dheeraj
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Sjögren, Thomas
    SAR Resolution Enhancement with Circular Aperture in Theory and Empirical Scenario2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    SAR systems synthesizing circular apertures have been shown to result in better spatial resolutions than the ones synthesizing linear apertures. The paper presents an investigation about the enhancement of SAR spatial resolutions with the use of circular aperture. A comparison between the spatial resolutions obtained with a SAR system synthesizing a circular aperture and with the same SAR system synthesizing a linear aperture is therefore carried out. The studying results are verified by the experimental SAR data set provided by the experimental ground-based SAR system of Blekinge Institute of Technology (BTH GB-SAR).

  • 496.
    Vu, Viet Thuy
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Ground Moving Target Detection and Estimation By Using Dual Speed SAR Platform2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The paper proposes a ground moving target detection and estimation method aiming at Ultra Wide Band and -Beam (UWB) Synthetic Aperture Radar (SAR) systems. The method is developed on the moving target detection by focusing technique and requires a SAR system flying with two different speeds during the integration time. The method allows us to detect ground moving target, even hidden by clutter, and to estimate the target parameters, i.e. speed and direction of motion. The accuracy of the estimations depends strongly on the computational cost and can therefore be controlled. The proposal is tested with the simulated CARABAS data.

  • 497.
    Vu, Viet Thuy
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Sjogren, Thomas
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Minardi, Michael
    Studying Csar Systems Using Irf-Csar2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, Impulse Response Function in Circular Synthetic Aperture Radar Imaging (IRF-CSAR), which is a special version of Impulse Response Function in Ultrawideband-Ultrawidebeam Synthetic Aperture Radar Imaging (IRF-USAR), is presented and shown to be valid for representing the CSAR image of a point-like scatterer. IRF-CSAR can therefore be used in studying different CSAR systems such as predicting the pattern of a point-like scatterer illuminated by a CSAR system, estimating resolution achieved by that system. Applying IRF-CSAR to define the image quality assessments for CSAR is also presented in the paper.

  • 498.
    Vu, Viet Thuy
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Sjögren, Thomas
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Ground Moving Target Detection and Estimation with Different Sar Linear Flight Tracks2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The paper proposes a groundmoving target detection and estimation method aiming at UltraWide Band and -Beam (UWB) Synthetic Aperture Radar (SAR) systems. The method is developed on the moving target detection by focusing technique and requires a SAR system flying with two different linear flight tracks. The method allows us to detect ground moving target, even hidden by clutter, and to estimate the target parameters such as speed and direction of motion. The accuracy of the estimations depends strongly on the computational cost and can therefore be controlled.

  • 499.
    Vu, Viet Thuy
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Sjögren, Thomas
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Moving Target Focusing with Normalized Relative Speed in Azimuth-Invarian Bistatic Sar2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Focusing moving targets with Normalized Relative Speed (NRS) for bistatic synthetic aperture radar (SAR) is discussed in this paper. The discussion concentrates on azimuth invariant bistatic geometry. The focusing approach for azimuth-invariant bistatic geometry is derived analytically. The validity of the proposed approach for other bistatic geometry like azimuth-variant is also investigated.

  • 500.
    Vu, Viet Thuy
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för matematik och naturvetenskap.
    Sjögren, Thomas
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för matematik och naturvetenskap.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för matematik och naturvetenskap.
    On Synthetic Aperture Radar Spatial Azimuth and Range Resolution Equations2012Ingår i: IEEE Transactions on Aerospace and Electronic Systems, ISSN 0018-9251, E-ISSN 1557-9603, Vol. 48, nr 2, s. 1764-1769Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper discusses spatial resolutions for narrowband narrowbeam (NB) synthetic aperture radar (SAR) as well as for ultrawideband ultrawidebeam (UWB) SAR. The similarity and difference between the impulse response function in NB SAR imaging (IRF-NSAR) - sinc function - and the impulse response function in UWB SAR imaging (IRF-USAR) is investigated and the result of this investigation shows that in the intensity interval from −6 dB to 0 dB, the behavior of IRF-NSAR and IRF-USAR in azimuth and range are similar. This is the basis for a derivation of new spatial resolution equations for UWB SAR based on −3 dB width or half power beamwidth (HPBW). The investigated result also shows that there exists the so-called HPBW narrowing/broadening factor in an IRF-USAR.

7891011 451 - 500 av 527
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf