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To ensure frequency stability in future low-inertia power grids, fast ancillary services such as fast frequency reserves (FFR) have been proposed. In this work, the coordination of conventional (slow) frequency containment reserves (FCR) with FFR is treated as a decentralized model matching problem. The design results in a dynamic virtual power plant (DVPP) whose aggregated output fulfills the system operator’s (SO’s) requirements in all time scales, while accounting for the capacity and bandwidth limitation of participating devices. This is illustrated in a 5-machine representation of the Nordic synchronous grid. In the Nordic grid, stability issues and bandwidth limitations associated with non-minimum phase zeros of hydropower is a well-known problem. By simulating the disconnection of a 1400 MW importing dc link, it is shown that the proposed DVPP design allows for coordinating fast FFR from wind, with slow FCR from hydro, while respecting dynamic limitations of all participating devices. The SO’s requirements are fulfilled in a realistic low-inertia scenario without the need to install battery storage or to waste wind energy by curtailing the wind turbines., QC 20230328

Autonomous vehicles have gained much importance over the last decade owing to their promising capabilities like improvement in overall traffic flow, reduction in pollution and elimination of human errors. However, when it comes to long-distance transportation or working in complex isolated environments like mines, various factors such as safety, fuel efficiency, transportation cost, robustness, and accuracy become very critical. This thesis, developed at the Connected and Autonomous Systems department of Scania AB in association with KTH, focuses on addressing the issues related to fuel efficiency, robustness and accuracy of an autonomous heavy-duty truck used for mining applications. First, in order to improve the state prediction capabilities of the simulation model, a comparative analysis of two dynamic bicycle models was performed. The first model used the empirical PAC2002 Magic Formula (MF) tyre model to generate the tyre forces, and the latter used a piece-wise Linear approximation of the former. On top of that, in order to account for the nonlinearities and time delays in the lateral direction, the steering dynamic equations were empirically derived and cascaded to the vehicle model. The fidelity of these models was tested against real experimental logs, and the best vehicle model was selected by striking a balance between accuracy and computational efficiency. The Dynamic bicycle model with piece-wise Linear approximation of tyre forces proved to tick-all-the-boxes by providing accurate state predictions within the acceptable error range and handling lateral accelerations up to 4 m/s2. Also, this model proved to be six times more computationally efficient than the industry-standard PAC2002 tyre model. Furthermore, in order to ensure smooth and accurate driving, several Model Predictive Control (MPC) formulations were tested on clothoid-based Single Lane Change (SLC), Double Lane Change (DLC) and Truncated Slalom trajectories with added disturbances in the i, Under det senaste årtiondet har utveckling av autonoma fordon blivit allt viktigare på grund av de stora möjligheterna till förbättringar av trafikflöden, minskade utsläpp av föroreningar och eliminering av mänskliga fel. När det gäller långdistanstransporter eller komplexa isolerade miljöer så som gruvor blir faktorer som bränsleeffektivitet, transportkostnad, robusthet och noggrannhet mycket viktiga. Detta examensarbete utvecklat vid avdelningen Connected and Autonomous Systems på Scania i samarbete med KTH fokuserar på frågor gällande bränsleeffektivitet, robusthet och exakthet hos en autonom tung lastbil i gruvmiljö. För att förbättra simuleringsmodellens tillståndsprediktioner, genomfördes en jämförande analys av två dynamiska fordonsmodeller. Den första modellen använde den empiriska däckmodellen PAC2002 Magic Formula (MF) för att approximera däckkrafterna, och den andra använde en stegvis linjär approximation av samma däckmodell. För att ta hänsyn till ickelinjäriteter och laterala tidsfördröjningar inkluderades empiriskt identifierade styrdynamiksekvationer i fordonsmodellen. Modellerna verifierades mot verkliga mätdata från fordon. Den bästa fordonsmodellen valdes genom att hitta en balans mellan noggrannhet och beräkningseffektivitet. Den Dynamiska fordonsmodellen med stegvis linjär approximation av däckkrafter visade goda resultat genom att ge noggranna tillståndsprediktioner inom det acceptabla felområdet och hantera sidoacceleration upp till 4 m/s2 . Den här modellen visade sig också vara sex gånger effektivare än PAC2002-däckmodellen. v För att säkerställa mjuk och korrekt körning testades flera MPC varianter på klotoidbaserade trajektorier av filbyte SLC, dubbelt filbyte DLC och slalom. Störningar i position, riktining och hastighet lades till startpositionen. En MPC med straff på rumslig avvikelse föreslås, vilket ger en länk mellan rumsdomän och tidsdomän. Den föreslagna regleringen visade sig vara en perfekt balans mellan bränsleeffektivitet, genom

Autonomous vehicles have gained much importance over the last decade owing to their promising capabilities like improvement in overall traffic flow, reduction in pollution and elimination of human errors. However, when it comes to long-distance transportation or working in complex isolated environments like mines, various factors such as safety, fuel efficiency, transportation cost, robustness, and accuracy become very critical. This thesis, developed at the Connected and Autonomous Systems department of Scania AB in association with KTH, focuses on addressing the issues related to fuel efficiency, robustness and accuracy of an autonomous heavy-duty truck used for mining applications. First, in order to improve the state prediction capabilities of the simulation model, a comparative analysis of two dynamic bicycle models was performed. The first model used the empirical PAC2002 Magic Formula (MF) tyre model to generate the tyre forces, and the latter used a piece-wise Linear approximation of the former. On top of that, in order to account for the nonlinearities and time delays in the lateral direction, the steering dynamic equations were empirically derived and cascaded to the vehicle model. The fidelity of these models was tested against real experimental logs, and the best vehicle model was selected by striking a balance between accuracy and computational efficiency. The Dynamic bicycle model with piece-wise Linear approximation of tyre forces proved to tick-all-the-boxes by providing accurate state predictions within the acceptable error range and handling lateral accelerations up to 4 m/s2. Also, this model proved to be six times more computationally efficient than the industry-standard PAC2002 tyre model. Furthermore, in order to ensure smooth and accurate driving, several Model Predictive Control (MPC) formulations were tested on clothoid-based Single Lane Change (SLC), Double Lane Change (DLC) and Truncated Slalom trajectories with added disturbances in the i, Under det senaste årtiondet har utveckling av autonoma fordon blivit allt viktigare på grund av de stora möjligheterna till förbättringar av trafikflöden, minskade utsläpp av föroreningar och eliminering av mänskliga fel. När det gäller långdistanstransporter eller komplexa isolerade miljöer så som gruvor blir faktorer som bränsleeffektivitet, transportkostnad, robusthet och noggrannhet mycket viktiga. Detta examensarbete utvecklat vid avdelningen Connected and Autonomous Systems på Scania i samarbete med KTH fokuserar på frågor gällande bränsleeffektivitet, robusthet och exakthet hos en autonom tung lastbil i gruvmiljö. För att förbättra simuleringsmodellens tillståndsprediktioner, genomfördes en jämförande analys av två dynamiska fordonsmodeller. Den första modellen använde den empiriska däckmodellen PAC2002 Magic Formula (MF) för att approximera däckkrafterna, och den andra använde en stegvis linjär approximation av samma däckmodell. För att ta hänsyn till ickelinjäriteter och laterala tidsfördröjningar inkluderades empiriskt identifierade styrdynamiksekvationer i fordonsmodellen. Modellerna verifierades mot verkliga mätdata från fordon. Den bästa fordonsmodellen valdes genom att hitta en balans mellan noggrannhet och beräkningseffektivitet. Den Dynamiska fordonsmodellen med stegvis linjär approximation av däckkrafter visade goda resultat genom att ge noggranna tillståndsprediktioner inom det acceptabla felområdet och hantera sidoacceleration upp till 4 m/s2 . Den här modellen visade sig också vara sex gånger effektivare än PAC2002-däckmodellen. v För att säkerställa mjuk och korrekt körning testades flera MPC varianter på klotoidbaserade trajektorier av filbyte SLC, dubbelt filbyte DLC och slalom. Störningar i position, riktining och hastighet lades till startpositionen. En MPC med straff på rumslig avvikelse föreslås, vilket ger en länk mellan rumsdomän och tidsdomän. Den föreslagna regleringen visade sig vara en perfekt balans mellan bränsleeffektivitet, genom

Model-Driven Engineering promotes the migration from code-centric to model-based software development. Systems consist of model collections integrating different concerns and perspectives, while semi-automated model transformations analyse quality attributes and generate executable code combining the information from these. Raising the abstraction level to models requires appropriate management technologies supporting the various software development activities. Among these, model comparison represents one of the most challenging tasks and plays an essential role in various modelling activities. Its hardness led researchers to propose a multitude of approaches adopting different approximation strategies and exploiting specific knowledge of the involved models. In this respect, almost no support is provided for the systematic evaluation of comparison approaches against specific scenarios and modelling practices, namely benchmarks. In this article we propose Benji, a framework for the automated generation of model comparison benchmarks. In particular, by giving a set of difference patterns and an initial model, users can generate model manipulation scenarios resulting from the application of the patterns on the model. The generation support provided by the framework obeys specific design principles that are considered as essential properties for the systematic evaluation of model comparison solutions, and are inherited from the general principles coming from evidence-based software engineering. The framework is validated through representative scenarios of model comparison benchmark generations.

An appropriate setting of eventual controller parameters for a derived controller structure represents an integral part of many control design approaches for dynamical systems. This contribution is aimed at a practically applicable and uncomplicated controller tuning method for linear time-invariant time delay systems (LTI-TDSs). It is based on placing the dominant poles as well as zeros of the given infinite-dimensional feedback control system by matching them with the desired ones given by known dynamical properties of a simple fixed finite-dimensional model. The desired placing is done successively by applying the Quasi-Continuous Shifting Algorithm (QCSA) first such that poles and zeros are forced to be as close as possible to those of the model. Concurrently, rests of both system spectra are shifted to the left as far as possible to minimize the spectral abscissa. The obtained results are then enhanced by a non-convex optimization technique applied to a selected objective function reflecting the distance of desired model roots from the eventual system ones and the spectral abscissae. Retarded LTI-TDS are primarily considered; however, systems with neutral delays are touched as well. The efficiency of the proposed method is proved via numerical examples in Matlab/Simulink environment. Some drawbacks and possible improvements or extensions of the algorithm for the future research are also concisely suggested to the reader. © 2018, Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature.

An appropriate setting of eventual controller parameters for a derived controller structure represents an integral part of many control design approaches for dynamical systems. This contribution is aimed at a practically applicable and uncomplicated controller tuning method for linear time-invariant time delay systems (LTI-TDSs). It is based on placing the dominant poles as well as zeros of the given infinite-dimensional feedback control system by matching them with the desired ones given by known dynamical properties of a simple fixed finite-dimensional model. The desired placing is done successively by applying the Quasi-Continuous Shifting Algorithm (QCSA) first such that poles and zeros are forced to be as close as possible to those of the model. Concurrently, rests of both system spectra are shifted to the left as far as possible to minimize the spectral abscissa. The obtained results are then enhanced by a non-convex optimization technique applied to a selected objective function reflecting the distance of desired model roots from the eventual system ones and the spectral abscissae. Retarded LTI-TDS are primarily considered; however, systems with neutral delays are touched as well. The efficiency of the proposed method is proved via numerical examples in Matlab/Simulink environment. Some drawbacks and possible improvements or extensions of the algorithm for the future research are also concisely suggested to the reader. © 2018, Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature.

Photo-lithographic stepper systems are used for manufacturing of integrated chips(IC). For incorporating more functionality and having more space chip manufacturing industries invest heavily to reduce the size of the structures on the chips. This directly requires the stepper system to operate in nanometer scale resolution. To achieve such high accuracy, the stepper system should be isolated from the external vibrations. Isolators are the auxiliary systems that protect the device from floor vibrations. In order to better understand how to tweak isolator components to boost the vibration isolation performance a parameterized multi body model of the system is the first step. From a system theoretical perspective, estimating the parameters of such a multi-body model is a problem on gray-box system identification. The state-of-the art approaches in this field estimates both the state transformation matrix and the system parameters. This increases the number of decision variables in the optimization problem. Very few results exist in which more than 6 system parameters have been estimated accurately. In this thesis we develop a framework for gray-box system identification comprising of PBSIDopt algorithm and H-infinity static output feedback synthesis. This approach bypasses the estimation of state transformation matrix. Also this optimization addresses the input output behavior directly which makes it conceptually simpler. We also explain how to judge whether the framework has estimated the parameters such that the input-output behavior of the system is captured. Our simulation results suggest that to estimate the 16 system parameters very accurately, precise knowledge of the inertial properties of the system is required. Nevertheless, there are other applications within vibration isolation where a multi body model which explains the data is sufficient. We expect our framework to aid the engineers at Zeiss for such applications., Mechanical, Maritime and Materials Engineering, Delft Center for Systems and Control

Photo-lithographic stepper systems are used for manufacturing of integrated chips(IC). For incorporating more functionality and having more space chip manufacturing industries invest heavily to reduce the size of the structures on the chips. This directly requires the stepper system to operate in nanometer scale resolution. To achieve such high accuracy, the stepper system should be isolated from the external vibrations. Isolators are the auxiliary systems that protect the device from floor vibrations. In order to better understand how to tweak isolator components to boost the vibration isolation performance a parameterized multi body model of the system is the first step. From a system theoretical perspective, estimating the parameters of such a multi-body model is a problem on gray-box system identification. The state-of-the art approaches in this field estimates both the state transformation matrix and the system parameters. This increases the number of decision variables in the optimization problem. Very few results exist in which more than 6 system parameters have been estimated accurately. In this thesis we develop a framework for gray-box system identification comprising of PBSIDopt algorithm and H-infinity static output feedback synthesis. This approach bypasses the estimation of state transformation matrix. Also this optimization addresses the input output behavior directly which makes it conceptually simpler. We also explain how to judge whether the framework has estimated the parameters such that the input-output behavior of the system is captured. Our simulation results suggest that to estimate the 16 system parameters very accurately, precise knowledge of the inertial properties of the system is required. Nevertheless, there are other applications within vibration isolation where a multi body model which explains the data is sufficient. We expect our framework to aid the engineers at Zeiss for such applications., Mechanical, Maritime and Materials Engineering, Delft Center for Systems and Control

In [1], a revised version of the Pole-Placement Shifting based controller tuning Algorithm (PPSA), a finite-dimensional model-matching controller tuning method for time-delay systems (TDS), was presented together with some suggestions about algorithm improvements and modifications. Its leading idea consists in the placing the dominant characteristic poles and zeros of the infinite-dimensional feedback control system with respect to the desired dynamics of the simple finite-dimensional matching model. So far, retarded TDS have been studied in the reign of the PPSA. This paper, however, brings a detailed case study on a more advanced and intricate neutral-type control feedback. Unstable controlled plant is selected in our example, in addition. The results indicate a very good applicability of the PPSA under some minor modifications of standard manipulations with the neutral-type delayed spectrum. © Springer International Publishing Switzerland 2015.

In [1], a revised version of the Pole-Placement Shifting based controller tuning Algorithm (PPSA), a finite-dimensional model-matching controller tuning method for time-delay systems (TDS), was presented together with some suggestions about algorithm improvements and modifications. Its leading idea consists in the placing the dominant characteristic poles and zeros of the infinite-dimensional feedback control system with respect to the desired dynamics of the simple finite-dimensional matching model. So far, retarded TDS have been studied in the reign of the PPSA. This paper, however, brings a detailed case study on a more advanced and intricate neutral-type control feedback. Unstable controlled plant is selected in our example, in addition. The results indicate a very good applicability of the PPSA under some minor modifications of standard manipulations with the neutral-type delayed spectrum. © Springer International Publishing Switzerland 2015.

This letter considers how to approximately reconstruct a cascade system from a given unstructured system estimate. Many system identification methods, including subspace methods, provide reliable but generally unstructured black-box models. The problem we consider is how to find cascade systems that are close to such black-box models. For this, we use model matching techniques and optimal weighted Hankel-norm approximation to obtain accurate low-order cascade systems. We show that it is possible to bound the reconstruction error in terms of an error tolerance parameter and weighted Hankel singular values. The suggested methods are illustrated on both a numerical example and a real double tank system with experimental data., QC 20140618

This letter considers how to approximately reconstruct a cascade system from a given unstructured system estimate. Many system identification methods, including subspace methods, provide reliable but generally unstructured black-box models. The problem we consider is how to find cascade systems that are close to such black-box models. For this, we use model matching techniques and optimal weighted Hankel-norm approximation to obtain accurate low-order cascade systems. We show that it is possible to bound the reconstruction error in terms of an error tolerance parameter and weighted Hankel singular values. The suggested methods are illustrated on both a numerical example and a real double tank system with experimental data., QC 20140618

This letter considers how to approximately reconstruct a cascade system from a given unstructured system estimate. Many system identification methods, including subspace methods, provide reliable but generally unstructured black-box models. The problem we consider is how to find cascade systems that are close to such black-box models. For this, we use model matching techniques and optimal weighted Hankel-norm approximation to obtain accurate low-order cascade systems. We show that it is possible to bound the reconstruction error in terms of an error tolerance parameter and weighted Hankel singular values. The suggested methods are illustrated on both a numerical example and a real double tank system with experimental data., QC 20140618

During the development of algebraic controller design in a special ring for time delay systems (TDSs) a problem of a suitable free controller parameters setting appeared. The first author of this contribution recently suggested a natural idea of placing the dominant characteristic numbers (poles) and zeros of the infinite-dimensional feedback control system on the basis of the desired overshoot for a simple finite-dimensional matching model and shifting of the rest of the spectrum. However, the original procedure called the Pole-Placement Shifting based controller tuning Algorithm (PPSA) was not developed and described entirely well. The aim of this paper is to revise the idea of the PPSA and suggest a possible ways how to improve or extend the algorithm. A concise illustrative example is attached to clarify the procedure for the reader as well.

During the development of algebraic controller design in a special ring for time delay systems (TDSs) a problem of a suitable free controller parameters setting appeared. The first author of this contribution recently suggested a natural idea of placing the dominant characteristic numbers (poles) and zeros of the infinite-dimensional feedback control system on the basis of the desired overshoot for a simple finite-dimensional matching model and shifting of the rest of the spectrum. However, the original procedure called the Pole-Placement Shifting based controller tuning Algorithm (PPSA) was not developed and described entirely well. The aim of this paper is to revise the idea of the PPSA and suggest a possible ways how to improve or extend the algorithm. A concise illustrative example is attached to clarify the procedure for the reader as well.

This letter considers how to approximately reconstruct a cascade system from a given unstructured system estimate. Many system identification methods, including subspace methods, provide reliable but generally unstructured black-box models. The problem we consider is how to find cascade systems that are close to such black-box models. For this, we use model matching techniques and optimal weighted Hankel-norm approximation to obtain accurate low-order cascade systems. We show that it is possible to bound the reconstruction error in terms of an error tolerance parameter and weighted Hankel singular values. The suggested methods are illustrated on both a numerical example and a real double tank system with experimental data., QC 20140618

This letter considers how to approximately reconstruct a cascade system from a given unstructured system estimate. Many system identification methods, including subspace methods, provide reliable but generally unstructured black-box models. The problem we consider is how to find cascade systems that are close to such black-box models. For this, we use model matching techniques and optimal weighted Hankel-norm approximation to obtain accurate low-order cascade systems. We show that it is possible to bound the reconstruction error in terms of an error tolerance parameter and weighted Hankel singular values. The suggested methods are illustrated on both a numerical example and a real double tank system with experimental data., QC 20140618

The recognition of underwater objects and obstacles by sonar has been explored in many forms, particularly through the use of high-resolution imaging sonar systems. This work explores a method of providing real-time obstacle avoidance and navigational position updating for an Autonomous Underwater Vehicle (AUV) by applying regression analysis and geometric interpretation to sonar range data obtained from a low-cost, lowresolution, fixed-beam sonar. The algorithm utilized by this method first develops a leastsquares fit for sonar range data in a 2-D manner. The parameters developed by this method are then compared to an environmental model for position identification. If no match is achieved, then by applying the known geometry of the acoustic signal, an estimate for a 3- D surface is derived. This derived 3-D surface is then added to the environmental model to enable accurate path planning and post-mission analysis information. This method is currently implemented on an operational AUV operating in a well-defined orthogonal environment at NPS. The paper also discusses the simulation of the sonar systems using a ray tracing technique in a real-time dynamic graphical simulation implemented on a Silicon Graphics IRIS workstation., http://archive.org/details/designimplementa00floy, Commander, United States Navy, Approved for public release; distribution is unlimited.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this thesis we describe an Ethernet traffic model. The model aims at matching multiple moments of the bit rate at several timescales. To match the model parameters to measured traffic, four methods have been developed and tested on real traffic traces. Once a model has been created, it can be used directly in a fluid flow performance analysis. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex., Ethernet är en av den vanligaste länk teknikerna, den används i lokala nätverk, trådlösa nätverk och stadsnätverk. Dock finns det en brist för trafikmodeller för Ethernet som är användbara i prestanda analys. I denna avhandling beskrivs en modell för Ethernet trafik. Modellen modellerar flera moment av bit intensiteten på flera tidsskalor. För att matcha modell parametrar mot mätt trafik så har fyra metoder utvecklats. När en modell har byggts, så kan den användas direkt i den stokastiska flödes modellen för prestanda beräkningar. Resultaten visar att när antalet källor ökar på en länk, så blir modellen bättre och mindre komplex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this thesis we describe an Ethernet traffic model. The model aims at matching multiple moments of the bit rate at several timescales. To match the model parameters to measured traffic, four methods have been developed and tested on real traffic traces. Once a model has been created, it can be used directly in a fluid flow performance analysis. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex., Ethernet är en av den vanligaste länk teknikerna, den används i lokala nätverk, trådlösa nätverk och stadsnätverk. Dock finns det en brist för trafikmodeller för Ethernet som är användbara i prestanda analys. I denna avhandling beskrivs en modell för Ethernet trafik. Modellen modellerar flera moment av bit intensiteten på flera tidsskalor. För att matcha modell parametrar mot mätt trafik så har fyra metoder utvecklats. När en modell har byggts, så kan den användas direkt i den stokastiska flödes modellen för prestanda beräkningar. Resultaten visar att när antalet källor ökar på en länk, så blir modellen bättre och mindre komplex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this thesis we describe an Ethernet traffic model. The model aims at matching multiple moments of the bit rate at several timescales. To match the model parameters to measured traffic, four methods have been developed and tested on real traffic traces. Once a model has been created, it can be used directly in a fluid flow performance analysis. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex., Ethernet är en av den vanligaste länk teknikerna, den används i lokala nätverk, trådlösa nätverk och stadsnätverk. Dock finns det en brist för trafikmodeller för Ethernet som är användbara i prestanda analys. I denna avhandling beskrivs en modell för Ethernet trafik. Modellen modellerar flera moment av bit intensiteten på flera tidsskalor. För att matcha modell parametrar mot mätt trafik så har fyra metoder utvecklats. När en modell har byggts, så kan den användas direkt i den stokastiska flödes modellen för prestanda beräkningar. Resultaten visar att när antalet källor ökar på en länk, så blir modellen bättre och mindre komplex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this thesis we describe an Ethernet traffic model. The model aims at matching multiple moments of the bit rate at several timescales. To match the model parameters to measured traffic, four methods have been developed and tested on real traffic traces. Once a model has been created, it can be used directly in a fluid flow performance analysis. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex., Ethernet är en av den vanligaste länk teknikerna, den används i lokala nätverk, trådlösa nätverk och stadsnätverk. Dock finns det en brist för trafikmodeller för Ethernet som är användbara i prestanda analys. I denna avhandling beskrivs en modell för Ethernet trafik. Modellen modellerar flera moment av bit intensiteten på flera tidsskalor. För att matcha modell parametrar mot mätt trafik så har fyra metoder utvecklats. När en modell har byggts, så kan den användas direkt i den stokastiska flödes modellen för prestanda beräkningar. Resultaten visar att när antalet källor ökar på en länk, så blir modellen bättre och mindre komplex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this thesis we describe an Ethernet traffic model. The model aims at matching multiple moments of the bit rate at several timescales. To match the model parameters to measured traffic, four methods have been developed and tested on real traffic traces. Once a model has been created, it can be used directly in a fluid flow performance analysis. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex., Ethernet är en av den vanligaste länk teknikerna, den används i lokala nätverk, trådlösa nätverk och stadsnätverk. Dock finns det en brist för trafikmodeller för Ethernet som är användbara i prestanda analys. I denna avhandling beskrivs en modell för Ethernet trafik. Modellen modellerar flera moment av bit intensiteten på flera tidsskalor. För att matcha modell parametrar mot mätt trafik så har fyra metoder utvecklats. När en modell har byggts, så kan den användas direkt i den stokastiska flödes modellen för prestanda beräkningar. Resultaten visar att när antalet källor ökar på en länk, så blir modellen bättre och mindre komplex.

Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this thesis we describe an Ethernet traffic model. The model aims at matching multiple moments of the bit rate at several timescales. To match the model parameters to measured traffic, four methods have been developed and tested on real traffic traces. Once a model has been created, it can be used directly in a fluid flow performance analysis. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex., Ethernet är en av den vanligaste länk teknikerna, den används i lokala nätverk, trådlösa nätverk och stadsnätverk. Dock finns det en brist för trafikmodeller för Ethernet som är användbara i prestanda analys. I denna avhandling beskrivs en modell för Ethernet trafik. Modellen modellerar flera moment av bit intensiteten på flera tidsskalor. För att matcha modell parametrar mot mätt trafik så har fyra metoder utvecklats. När en modell har byggts, så kan den användas direkt i den stokastiska flödes modellen för prestanda beräkningar. Resultaten visar att när antalet källor ökar på en länk, så blir modellen bättre och mindre komplex.

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This paper proposes a new technique for frequency shaping of the closed-loop system. The technique does not involve any weighting function for shaping, which is often used in the conventional H∞ control theory, but selects a desirable analytic function from a set of H∞ suboptimal solutions with a bounded degree. The Nevanlinna-Pick interpolation theory with a degree bound plays a central role in deriving shaping strategies of the closed-loop frequency responses. One example illustrates the efficiency of the proposed method by comparing it with a conventional method in H∞ control., QC 20160316

Exact knowledge of the position of a vehicle is a fundamental problem in mobile robot applications. In the search for a solution, researchers and engineers have developed a variety of systems, sensors, and techniques for mobile robot positioning. This paper provides a review of relevant mobile robot positioning technologies. The paper defines seven categories for positioning systems: (1) Odometry, (2) Inertial Navigation, (3) Magnetic Compasses, (4) Active Beacons, (5) Global Positioning Systems, (6) Landmark Navigation, and (7) Model Matching. The characteristics of each category are discussed and examples of existing technologies are given for each category. The field of mobile robot navigation is active and vibrant, with more great systems and ideas being developed continuously. For this reason the examples presented in this paper serve only to represent their respective categories; they do not represent a judgment by the authors. Many ingenious approaches can be found in the literature, although, for reasons of brevity, not all could be cited in this paper. The appendix contains a tabular comparison of the positioning systems discussed in this review that includes system and description, features, accuracy (position), accuracy (orientation), effective range, and source of information. (47 refs.), Pub. in the Journal of Robotic Systems, Special Issue on Mobile Robots, v14 n4, p231-249. Prepared in collaboration with the Advanced Technologies Lab and the Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI. The original document contains color images.

This paper considers the problem of look-ahead robust tracking for a non-minimum phase system under a sensitivity constraint. Because of non-minimum phase zeros, the exact tracking of arbitrary reference input is impossible. However, with an introduction of some delay, tracking is possible within any given `'tolerance'' epsilon(1) > 0. It is shown in the paper that the minimum delay required to satisfy the tracking performance is decoupled from a sensitivity/disturbance rejection constraint. Moreover, it is shown that calculation of the minimum delay reduces to a binary search problem.

This paper considers the problem of look-ahead robust tracking for a non-minimum phase system under a sensitivity constraint. Because of non-minimum phase zeros, the exact tracking of arbitrary reference input is impossible. However, with an introduction of some delay, tracking is possible within any given `'tolerance'' epsilon(1) > 0. It is shown in the paper that the minimum delay required to satisfy the tracking performance is decoupled from a sensitivity/disturbance rejection constraint. Moreover, it is shown that calculation of the minimum delay reduces to a binary search problem.

This paper considers the problem of look-ahead robust tracking for a non-minimum phase system under a sensitivity constraint. Because of non-minimum phase zeros, the exact tracking of arbitrary reference input is impossible. However, with an introduction of some delay, tracking is possible within any given `'tolerance'' epsilon(1) > 0. It is shown in the paper that the minimum delay required to satisfy the tracking performance is decoupled from a sensitivity/disturbance rejection constraint. Moreover, it is shown that calculation of the minimum delay reduces to a binary search problem.

The recognition of underwater objects and obstacles by sonar has been explored in many forms, particularly through the use of high-resolution imaging sonar systems. This work explores a method of providing real-time obstacle avoidance and navigational position updating for an Autonomous Underwater Vehicles (AUV) by applying regression analysis and geometric interpretation of sonar range data obtained from a low-cost, low-resolution, fixed-beam sonar. The algorithm utilized by this method first develops a least-squares fit for sonar range data in a 2-D manner. The parameters developed by this method are then compared to an environmental model for position identification. If no match is achieved, then by applying the known geometry of the acoustic signal, an estimate for a 3-D surface is derived. The derived 3-D surface is then added to the environmental model to enable accurate path planning and post-mission analysis information. This method is currently implemented on an operational AUV operating in a well-defined orthogonal environment at NPS. The paper also discusses the simulation of the sonar systems using a ray tracing technique in a real-time dynamic graphical simulation implemented on a Silicon Graphics IRIS workstation.