| 1. |
- Agelis, Sacki, et al.
(författare)
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Reconfigurable optical interconnection system supporting concurrent application-specific parallel computing
- 2005
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Ingår i: 17th Symposium on Computer Architecture and High Performance Computing. - Washington, DC, USA : IEEE Computer Society. - 076952446X ; , s. 44-51
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Konferensbidrag (refereegranskat)abstract
- Application specific architectures are highly desirable in embedded parallel computing systems at the same time as designers strive for using one embedded parallel computing platform for several applications. If this can be achieved, the cost can be decreased in comparison to using several different embedded parallel computing systems. This paper presents a novel approach of running several high-performance applications concurrently on one single parallel computing system. By using a reconfigurable backplane interconnection system, the applications can be run efficiently with high network flexibility since the interconnect network can be adapted to fit the application that is being processed for the moment. More precisely, this paper investigates how the space time adaptive processing (STAP) radar algorithm and the stripmap synthetic aperture radar (SAR) algorithm can be mapped on a multi-cluster processing system with a reconfigurable optical interconnection system realized by a micro-optical-electrical mechanical system (MOEMS) crossbars. The paper describes the reconfigurable platform, the two algorithms and how they individually can be mapped on the targeted multiprocessor system. It is also described how these two applications can be mapped simultaneously on the optical reconfigurable platform. Implications and requirements on communication bandwidth and processor performance in different critical points of the two applications are presented. The results of the analysis show that an implementation is feasible with today's MOEMS technology, and that the two applications can be successfully run in a time-sharing scheme, both at the processing side and at the access for interconnection bandwidth.
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| 2. |
- Byttner, Stefan
(författare)
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Real-time control of an SI engine using ion current based algorithms
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Reducing emissions and improving fuel efficiency in automobiles are today important issues. New sensor techniques are developed to extract detailed combustion information to enable closed loop engine control. This thesis is about a virtual sensor; measuring an ion current inside the cylinder by using the already existing spark plug, followed by signal processing for estimation of combustion parameters. First, the thesis aims to show that the ion current signal can be used for closed loop control of Exhaust Gas Recirculation (EGR). Use of EGR is very common in modern automobiles because of the potential reduction of NOx emissions and fuel consumption, but using too much EGR can have the reverse effect (e.g. increased fuel consumption and driveability problems). Algorithms for estimating combustion variability are proposed and a closed loop scheme for controlling an EGR valve is demonstrated for driving on the highway in a SAAB 9000. Estimation of the pressure peak position is treated for closed loop control of ignition timing. Such estimation can be performed with the ion current but may not work if a fuel additive is used. Different methods are compared and it is shown that using a fuel additive may even improve the estimation accuracy of the pressure peak position with about 25%. An algorithm is also proposed to estimate the pressure peak position even in presence of EGR. Strategies for transient control of the air-fuel ratio are also compared. Air-fuel ratio control is important because even small deviations from the stoichiometric value can result in significantly increased emissions. It is found that a neural network based controller had the best performance with approximately 23% lower RMS error than the adapted standard control module.
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| 3. |
- Larsson, Tony, et al.
(författare)
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T4 - Telematics for Totally Transparent Transports
- 2005
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Ingår i: 2005 IEEE Intelligent Transportation Systems Conference (ITSC). - New York : IEEE Press. - 0780392159 ; , s. 467-472
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Konferensbidrag (refereegranskat)abstract
- Transports can be made safer, more secure and efficient by help of telemetry and tracking on-line in real time. T4 is a system architecture aimed to support the development of telematic services for transparent tracking and surveillance monitoring of goods transported by different means on a global scale. The main idea is to focus on the transported pallets or parcels instead of the vehicles moving them. To enable rapid response to new customer requirements and to support remote management of field equipment, software implemented services are designed, packaged, deployed and mediated using XML, Java and the OSGi software technology standards.
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| 4. |
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| 5. |
- Nilsson, Kenneth, et al.
(författare)
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Registration of fingerprints by complex filtering and by 1D projections of orientation images
- 2005
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Ingår i: Audio- and video-based biometric person authentication. - Berlin : Springer Berlin/Heidelberg. - 9783540278870 - 3540278877 ; , s. 171-183
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Konferensbidrag (refereegranskat)abstract
- When selecting a registration method for fingerprints, the choice is often between a minutiae based or an orientation field based registration method. In selecting a combination of both methods, instead of selecting one of the methods, we obtain a one modality multi-expert registration system. If the combined methods are based on di#erent features in the fingerprint, e.g. the minutiae points respective the orientation field, they are uncorrelated and a higher registration performance can be expected compared to when only one of the methods are used. In this paper two registration methods are discussed that do not use minutiae points, and are therefore candidates to be combined with a minutiae based registration method to build a multi-expert registration system for fingerprints with expected high registration performance. Both methods use complex orientations fields but produce uncorrelated results by construction. One method uses the position and geometric orientation of symmetry points, i.e. the singular points (SPs) in the fingerprint to estimate the translation respectively the rotation parameter in the Euclidean transformation. The second method uses 1D projections of orientation images to find the transformation parameters. Experimental results are reported.
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| 6. |
- Nilsson, Kenneth
(författare)
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Symmetry Filters Applied to Fingerprints : Representation, Feature extraction and Registration
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A common framework for feature extraction in fingerprints is proposed by use of certain symmetries. The proposal includes representation, filters, and filtering techniques for common features including minutiae points, singular points and the ridge and valley patterns.The filters are complex and are designed to identify certain symmetries called rotational symmetries and they are applied to the squared complex gradient field of an image. The filters are used as extractors for known fingerprint features. The filter response magnitude is a certainty measure for existence of a symmetry and its argument is the spatial orientation of that symmetry. This means that the position and the spatial orientation of the fingerprint feature are estimated in a single filtering step jointly. In the proposed framework the position and orientation of singular points are extracted using a multi-scale filtering technique. This strategy is taken to increase the signal-to-noise ratio in the extraction and can be done because singular points have a large spatial support from the orientation field. Experiments show that position is extracted by a precision of 5 ± 3 pixels1 and the orientation by a precision of 0 ± 4° with an EER of approximately 4%. The estimated position and orientation of singular points are used in an alignment experiment which yielded an unbiased alignment error with a standard deviation of 13 pixels 1.A one modality multi-expert registration experiment is presented using singular points and orientation images to estimate the registration parameters.1A fingerprint wavelength is in average 10 pixels.
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| 7. |
- Xiao, Li
(författare)
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Gear tribology : friction and surface topography
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The quest for energy efficiency leads to the development of highly efficient power transmissions for vehicles. Gears are some of the most rugged and durable torque transmitters among machine elements. Friction between sliding surfaces at gear teeth is one major source of power loss. To increase efficiency and reduce damage accumulation in gears has always been a background motivation to this thesis. It focuses on the frictional performance of manufactured gear surfaces with emphasis on the effect of surface topography and the orientation of its lay.To achieve the goal of this work, a test rig was designed and constructed. The rig makes it possible to examine gear tooth friction on double crowned rollers. Five alternative gear-finishing processes are implemented in roller surface preparation. They comprise grinding, shotpeening, phosphating, chemical deburring and DLC coating. Theoretically, a friction model is suggested which helps to explain some of the testing results. Advanced surface metrology techniques and statistical tools are implemented in identifying surface features that influence friction.The result demonstrates that surface topography is a significant factor affecting the lubricated frictional behaviour. For ground-finishing, the smoother the surfaces are finished, the lower friction coefficient they show. Chemical deburring and DLC coating as well as certain degrees of phosphating provide minimum friction coefficient and improved load carrying capacity, which are competitive to fine-ground finishing. Properly designed lay combinations of meshing gear surfaces can minimise friction and improve gear transmission efficiency. Theoretically, the friction coefficient can be explained by means of a combination of the slide-to-roll ratio and the real mean contact pressure within the range of loads considered in this thesis. Finally, features that correlate surface topography to friction are identified.
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| 8. |
- Åhlander, Anders, et al.
(författare)
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Meeting Engineer Efficiency Requirements in Highly Parallel Signal Processing by Using Platforms
- 2005
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Ingår i: Proceedings of the 17th IASTED International Conference on Parallel and Distributed Computing and Systems. - Anaheim : ACTA Press. - 0889865256 - 9780889865259 ; , s. 693-700
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Konferensbidrag (populärvet., debatt m.m.)abstract
- One of the driving forces behind the development of new, highly parallel architectures is the need for embedded high-performance computing. The development of advanced applications on such architectures is, however, potentially connected to high costs. Cost-effective devel opment requires tools and processes that provide engineer efficiency, in this case tools and processes that help the developer master the application complexity. Related to engineer efficiency are the important concepts of system sustainability and flexibility. To address these issues, a platform approach can be taken. The platform should offer an understandable and stable development model, and at the same time give the possibility to take advantage of the rapid technology development, including the use of new parallel architectures. Thus it must support multiple hard ware targets, and the development model should decouple application development from mapping aspects. Two radar signal processing examples, one compute-intensive STAP and one data-intensive SAR, are used to illustrate the need. The GEPARD platform is presented as an example of our approach, and we argue that the described platform is a good fit for advanced signal processing development, facilitating the desired engineer efficiency, sustainability, and flexibility.
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| 9. |
- Malmberg, Donald, et al.
(författare)
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Preliminary microwave measurements on liquid stags
- 2005
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Ingår i: Ironmaking & steelmaking. - London : Maney Publishing. - 0301-9233 .- 1743-2812. ; 32:1, s. 61-67
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Tidskriftsartikel (refereegranskat)abstract
- Microwave technology has for decades been a tool for astronomers in their work to map and understand the complexities of the universe in terms of composition and extent but it is also used at laboratory scale by spectroscopists to examine the properties of atomic and molecular compounds. This paper discusses the use of microwave technology for the investigation of liquid slag structures. Preliminary results indicate that alteration of slag composition could be correlated to the measured microwave refractive index. Investigations have been performed on Al2 O3 -CaO-SiO2.
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| 10. |
- Soleimani Mohseni, Mohsen
(författare)
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Modelling and Intelligent Climate Control of Buildings
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of the work presented in this thesis is to examine the possibilities of different control techniques together with intelligent building technology to improve the indoor climate and/or the energy efficiency of buildings. In particular, the possibilities of measuring more variables and using them as input to the controllers are examined. The first part of the thesis deals with different ways to obtain dynamic models for climate systems in buildings. A large part of the thesis then deals with the feed-forward control strategy and how it affects the indoor climate and the energy use. The main conclusion, drawn from the simulations in this part is that a more extensive use of feed-forward from internal disturbances could be very advantageous in many temperature-control applications. It gives better controller performance, and, at the same time, it will often reduce the energy use. Different controllers (P, PI, PID and ON/OFF with and without dead-band) used for indoor climate control are also investigated in this thesis. The results show that simple controllers like an ON/OFF controller with dead-band or a P-controller often performs better than more advanced controllers in many temperature-control applications. Similar types of controllers have also been investigated when they are used in a demand-control ventilation (DCV) system. The results show that there is a large potential of reducing the outdoor air flow rate by using a DCV-system instead of a base/forced ventilation system. However, the differences between different controllers in a DCV-system are of less importance in these systems. A large part of this thesis is about the problem how to develop mathematical models for prediction of the indoor temperature using linear models as well as non-linear artificial neural network (ANN) models. The results show that neural network models give more accurate predictions of indoor temperature than linear models. ANN-models have also been used for estimation of the operative temperature in buildings. It is shown that the operative temperature can be estimated fairly well by using variables which are more easily measured and that ANN-models give better estimations than linear models. Finally, neural networks have also been used in a new method for (self) tuning of PI and PID controllers. By measuring a number of points at the step-response of a process and using them as input to a successfully trained neural network, the network can estimate the PI and PID parameters with good accuracy for the same process according to well-known tuning rules for PI and PID controllers.
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