Change search
Refine search result
12 1 - 50 of 62
Cite
Citation style
• apa
• harvard1
• ieee
• modern-language-association-8th-edition
• vancouver
• Other style
More styles
Language
• de-DE
• en-GB
• en-US
• fi-FI
• nn-NO
• nn-NB
• sv-SE
• Other locale
More languages
Output format
• html
• text
• asciidoc
• rtf
Rows per page
• 5
• 10
• 20
• 50
• 100
• 250
Sort
• Standard (Relevance)
• Author A-Ö
• Author Ö-A
• Title A-Ö
• Title Ö-A
• Publication type A-Ö
• Publication type Ö-A
• Issued (Oldest first)
• Created (Oldest first)
• Last updated (Oldest first)
• Disputation date (earliest first)
• Disputation date (latest first)
• Standard (Relevance)
• Author A-Ö
• Author Ö-A
• Title A-Ö
• Title Ö-A
• Publication type A-Ö
• Publication type Ö-A
• Issued (Oldest first)
• Created (Oldest first)
• Last updated (Oldest first)
• Disputation date (earliest first)
• Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
• 1.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
Linear Prediction Error Methods for Stochastic Nonlinear Models2019In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 105, p. 49-63Article in journal (Refereed)

The estimation problem for stochastic parametric nonlinear dynamical models is recognized to be challenging. The main difficulty is the intractability of the likelihood function and the optimal one-step ahead predictor. In this paper, we present relatively simple prediction error methods based on non-stationary predictors that are linear in the outputs. They can be seen as extensions of the linear identification methods for the case where the hypothesized model is stochastic and nonlinear. The resulting estimators are defined by analytically tractable objective functions in several common cases. It is shown that, under certain identifiability and standard regularity conditions, the estimators are consistent and asymptotically normal. We discuss the relationship between the suggested estimators and those based on second-order equivalent models as well as the maximum likelihood method. The paper is concluded with a numerical simulation example as well as a real-data benchmark problem.

The full text will be freely available from 2021-04-01 16:05
• 2.
Uppsala Univ, Signal Proc, Uppsala, Sweden.;Univ Newcastle, Dept Elect & Comp Engn, Callaghan, NSW, Australia..
ABB Corp, Vasteras, Sweden.. Scania CV, Sodertalje, Sweden.. Linkoping Univ, Linkoping, Sweden.;Univ Newcastle, Callaghan, NSW, Australia.;Royal Inst Technol, Stockholm, Sweden.;ABB Corp Res, Vasteras, Sweden.. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Decision and Control Systems (Automatic Control). JGC Corp, Yokohama, Kanagawa, Japan. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Decision and Control Systems (Automatic Control). Univ Newcastle, Ctr Complex Dynam Syst & Control, Callaghan, NSW, Australia.;Uppsala Univ, Signals & Syst Div, Uppsala, Sweden.. Iggesund Mill, Maintenance Technol Dev, Iggesund Paperboard, Sweden.. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Decision and Control Systems (Automatic Control). CALTECH, Pasadena, CA 91125 USA.;MIT, Lab Informat & Decis Syst, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
Toward Wireless Control in Industrial Process Automation: A Case Study at a Paper Mill2019In: IEEE Control Systems Magazine, ISSN 1066-033X, Vol. 39, no 5, p. 36-57Article in journal (Refereed)

Wireless sensors and networks are used only occasionally in current control loops in the process industry. With rapid developments in embedded and highperformance computing, wireless communication, and cloud technology, drastic changes in the architecture and operation of industrial automation systems seem more likely than ever. These changes are driven by ever-growing demands on production quality and flexibility. However, as discussed in "Summary," there are several research obstacles to overcome. The radio communication environment in the process industry is often troublesome, as the environment is frequently cluttered with large metal objects, moving machines and vehicles, and processes emitting radio disturbances [1], [2]. The successful deployment of a wireless control system in such an environment requires careful design of communication links and network protocols as well as robust and reconfigurable control algorithms.

• 3.
Electrical Engineering, University of Engineering and Technology of Peshawar, Pakistan.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Information Science and Engineering. Telecommunications and Systems Engineering, Universitat Autònoma de Barcelona, Spain. Universitat Autònoma de Barcelona, Spain.
Kronecker-Based Fusion Rule for Cooperative Spectrum Sensing with Multi-Antenna Receivers2014In: Electronics, ISSN 2079-9292, Vol. 3, no 4, p. 675-688Article in journal (Refereed)

This paper considers a novel fusion rule for spectrum sensing scheme for a cognitive radio network with multi-antenna receivers. The proposed scheme exploits the fact that when any primary signal is present, measurements are spatially correlated due to presence of inter-antenna and inter-receiver spatial correlation. In order to exploit this spatial structure, the generalized likelihood ratio test (GLRT) operates with the determinant of the sample covariance matrix. Therefore, it depends on the sample size N and the dimensionality of the received data (i.e., the number of receivers K and antennas L). However, when the dimensionality fK; Lg is on the order, or larger than the sample size N, the GLRT degenerates due to the ill-conditioning of the sample covariance matrix. In order to circumvent this issue, we propose two techniques that exploit the inner spatial structure of the received observations by using single pair and multi-pairs Kronecker products. The performance of the proposed detectors is evaluated by means of numerical simulations, showing important advantages with respect to the traditional (i.e., unstructured) GLRT approach.

• 4.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Robotics, Perception and Learning, RPL.
Dual-Arm Robotic Manipulation under Uncertainties and Task-Based Redundancy2019Doctoral thesis, comprehensive summary (Other academic)

Robotic manipulators are mostly employed in industrial environments, where their tasks can be prescribed with little to no uncertainty. This is possible in scenarios where the deployment time of robot workcells is not prohibitive, such as in the automotive industry. In other contexts, however, the time cost of setting up a classical robotic automation workcell is often prohibitive. This is the case with cellphone manufacturing, for example, which is currently mostly executed by human workers. Robotic automation is nevertheless desirable in these human-centric environments, as a robot can automate the most tedious parts of an assembly. To deploy robots in these environments, however, requires an ability to deal with uncertainties and to robustly execute any given task. In this thesis, we discuss two topics related to autonomous robotic manipulation. First, we address parametric uncertainties in manipulation tasks, such as the location of contacts during the execution of an assembly. We propose and experimentally evaluate two methods that rely on force and torque measurements to produce estimates of task related uncertainties: a method for dexterous manipulation under uncertainties which relies on a compliant rotational degree of freedom at the robot's gripper grasp point and exploits contact  with an external surface, and a cooperative manipulation system which is able to identify the kinematics of a two degrees of freedom mechanism. Then, we consider redundancies in dual-arm robotic manipulation. Dual-armed robots offer a large degree of redundancy which can be exploited to ensure a more robust task execution. When executing an assembly task, for instance, robots can freely change the location of the assembly in their workspace without affecting the task execution. We discuss methods that explore these types of redundancies in relative motion tasks in the form of asymmetries in their execution. Finally, we approach the converse problem by presenting a system which is able to balance measured forces and torques at its end-effectors by leveraging relative motion between them, while grasping a rigid tray. This is achieved through discrete sliding of the grasp points, which constitutes a novel application of bimanual dexterous manipulation.

• 5. Arnela, Marc
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Speech, Music and Hearing, TMH, Speech Communication and Technology.
MRI-based vocal tract representations for the three-dimensional finite element synthesis of diphthongs2019In: IEEE Transactions on Audio, Speech, and Language Processing, ISSN 1558-7916, E-ISSN 1558-7924, Vol. 27, no 12, p. 2173-2182Article in journal (Refereed)

The synthesis of diphthongs in three-dimensions (3D) involves the simulation of acoustic waves propagating through a complex 3D vocal tract geometry that deforms over time. Accurate 3D vocal tract geometries can be extracted from Magnetic Resonance Imaging (MRI), but due to long acquisition times, only static sounds can be currently studied with an adequate spatial resolution. In this work, 3D dynamic vocal tract representations are built to generate diphthongs, based on a set of cross-sections extracted from MRI-based vocal tract geometries of static vowel sounds. A diphthong can then be easily generated by interpolating the location, orientation and shape of these cross-sections, thus avoiding the interpolation of full 3D geometries. Two options are explored to extract the cross-sections. The first one is based on an adaptive grid (AG), which extracts the cross-sections perpendicular to the vocal tract midline, whereas the second one resorts to a semi-polar grid (SPG) strategy, which fixes the cross-section orientations. The finite element method (FEM) has been used to solve the mixed wave equation and synthesize diphthongs [${\alpha i}$] and [${\alpha u}$] in the dynamic 3D vocal tracts. The outputs from a 1D acoustic model based on the Transfer Matrix Method have also been included for comparison. The results show that the SPG and AG provide very close solutions in 3D, whereas significant differences are observed when using them in 1D. The SPG dynamic vocal tract representation is recommended for 3D simulations because it helps to prevent the collision of adjacent cross-sections.

• 6.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering. Power Systems Laboratory, ETH Zurich, Switzerland. Power Systems Laboratory, ETH Zurich, Switzerland.
Smart Meter Privacy Control Strategy Including Energy Storage Degradation2019In: 2019 IEEE Milan PowerTech, IEEE, 2019Conference paper (Refereed)

In this paper, we present a degradation-aware privacy control strategy for smart meters by taking into account the capacity fade and energy loss of the battery, which has not been included previously. The energy management strategy is designed by minimizing the weighted sum of both privacy loss and total energy storage losses, where the weightage is set using a trade-off parameter. The privacy loss is measured in terms of Bayesian risk of an unauthorized hypothesis test. By making first-order Markov assumptions, the stochastic parameters of energy loss and capacity fade of the energy storage system are modelled using degradation maps. Using household power consumption data from the ECO dataset, the proposed control strategy is numerically evaluated for different trade-off parameters. Results show that, by including the degradation losses in the design of the privacy-enhancing control strategy, significant improvement in battery life can be achieved, in general, at the expense of some privacy loss.

• 7.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Robotics, Perception and Learning, RPL.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Robotics, Perception and Learning, RPL.
Integrated motion planning and control under metric interval temporal logic specifications2019In: 2019 18th European Control Conference, ECC 2019, Institute of Electrical and Electronics Engineers (IEEE), 2019, p. 2042-2049, article id 8795925Conference paper (Refereed)

This paper proposes an approach that combines motion planning and hybrid feedback control design in order to find and follow trajectories fulfilling a given complex mission involving time constraints. We use Metric Interval Temporal Logic (MITL) as a rich and rigorous formalism to specify such missions. The solution builds on three main steps: (i) using sampling-based motion planning methods and the untimed version of the mission specification in the form of Zone automaton, we find a sequence of waypoints in the workspace; (ii) based on the clock zones from the satisfying run on the Zone automaton, we compute time-stamps at which these waypoints should be reached; and (iii) to control the system to connect two waypoints in the desired time, we design a low-level feedback controller leveraging Time-varying Control Barrier Functions. Illustrative simulation results are included.

• 8.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering.
On the Mutual Information of Two Boolean Functions, with Application to Privacy2019In: Proceedings 2019 IEEE International Symposium on Information Theory (ISIT), IEEE , 2019, p. 1197-1201Conference paper (Refereed)

We investigate the behavior of the mutual information between two Boolean functions of correlated binary strings. The covariance of these functions is found to be a crucial parameter in the aforementioned mutual information. We then apply this result in the analysis of a specific privacy problem where a user observes a random binary string. Under particular conditions, we characterize the optimal strategy for communicating the outcomes of a function of said string while preventing to leak any information about a different function.

• 9.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. Max Planck Institute for Intelligent Systems.
Fast and Resource-Efficient Control of Wireless Cyber-Physical Systems2019Licentiate thesis, monograph (Other academic)

Cyber-physical systems (CPSs) tightly integrate physical processes with computing and communication to autonomously interact with the surrounding environment.This enables emerging applications such as autonomous driving, coordinated flightof swarms of drones, or smart factories. However, current technology does notprovide the reliability and flexibility to realize those applications. Challenges arisefrom wireless communication between the agents and from the complexity of thesystem dynamics. In this thesis, we take on these challenges and present three maincontributions.We first consider imperfections inherent in wireless networks, such as communication delays and message losses, through a tight co-design. We tame the imperfectionsto the extent possible and address the remaining uncertainties with a suitable controldesign. That way, we can guarantee stability of the overall system and demonstratefeedback control over a wireless multi-hop network at update rates of 20-50 ms.If multiple agents use the same wireless network in a wireless CPS, limitedbandwidth is a particular challenge. In our second contribution, we present aframework that allows agents to predict their future communication needs. Thisallows the network to schedule resources to agents that are in need of communication.In this way, the limited resource communication can be used in an efficient manner.As a third contribution, to increase the flexibility of designs, we introduce machinelearning techniques. We present two different approaches. In the first approach,we enable systems to automatically learn their system dynamics in case the truedynamics diverge from the available model. Thus, we get rid of the assumption ofhaving an accurate system model available for all agents. In the second approach, wepropose a framework to directly learn actuation strategies that respect bandwidthconstraints. Such approaches are completely independent of a system model andstraightforwardly extend to nonlinear settings. Therefore, they are also suitable forapplications with complex system dynamics.

• 10.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
A hybrid controller for obstacle avoidance in an n-dimensional euclidean space2019In: 2019 18th European Control Conference, ECC 2019, Institute of Electrical and Electronics Engineers (IEEE), 2019, p. 764-769, article id 8795713Conference paper (Refereed)

For a vehicle moving in an n-dimensional Euclidean space, we present a construction of a hybrid feedback that guarantees both global asymptotic stabilization of a reference position and avoidance of an obstacle corresponding to a bounded spherical region. The proposed hybrid control algorithm switches between two modes of operation: stabilization (motion-to-goal) and avoidance (boundary-following). The geometric construction of the flow and jump sets of the hybrid controller, exploiting a hysteresis region, guarantees robust switching (chattering-free) between stabilization and avoidance. Simulation results illustrate the performance of the proposed hybrid control approach for a 3-dimensional scenario.

• 11.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
Micromachined Waveguides with Integrated Silicon Absorbers and Attenuators at 220–325 GHz2018In: IEEE MTT-S International Microwave Symposium, IEEE conference proceedings, 2018 / [ed] IEEE, IEEE, 2018Conference paper (Refereed)

This paper reports for the first time on micromachined waveguides with integrated micromachined silicon absorbers. In contrast to epoxy-based microwave absorbers, micromachined lossy silicon absorbers are fully compatible with high temperature fabrication and assembly processes for micromachined waveguides. Furthermore, micromachining enables the fabrication of exact, near ideal taper tips for the silicon absorbers, whereas the tip of epoxy-based absorbers cannot be shaped accurately and reproducibly for small waveguides. Silicon of different conductivity is a very well understood and characterized dielectric material, in contrast to conventional absorber materials which are not specified above 60 GHz. Micromachined silicon waveguides with integrated absorbers and attenuators were designed, fabricated and characterized in the frequency band of 220 – 325 GHz. The return and insertion loss for various taper-geometry variations of double-tip tapered absorbers and attenuators was studied. The average return loss for the best investigated device is 19 dB over the whole band. The insertion loss of the two-port attenuators is 16 – 33 dB for different designs and shows an excellent agreement to the simulated results. The best measured devices of the one-port absorbers exhibit an average and worst-case return loss of 22 dB and 14 dB, respectively, over the whole band. The return loss is not characterized by a good simulation-measurement match, which is most likely attributed to placement tolerances of the absorbers in the waveguide cavities affecting the return but not the insertion loss.

• 12.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Distributed Stochastic Programming with Applications to Large-Scale Hydropower Operations2019Licentiate thesis, monograph (Other academic)

Stochastic programming is a subfield of mathematical programming concerned with optimization problems subjected to uncertainty. Many engineering problems with random elements can be accurately modeled as a stochastic program. In particular, decision problems associated with hydropower operations motivate the application of stochastic programming. When complex decision-support problems are considered, the corresponding stochastic programming models often grow too large to store and solve on a single computer. This clarifies the need for parallel approaches that could enable efficient treatment of large-scale stochastic programs in a distributed environment. In this thesis, we develop mathematical and computational tools in order to facilitate distributed stochastic programs that can be efficiently stored and solved.

First, we present a software framework for stochastic programming implemented in the Julia language. A key feature of the framework is the support for distributing stochastic programs in memory. Moreover, the framework includes a large set of structure-exploiting algorithms for solving stochastic programming problems. These algorithms are based on the classical L-shaped and progressive-hedging algorithms and can run in parallel on distributed stochastic programs. The distributed performance of our software tools is improved by exploring algorithmic innovations and software patterns. We present the architecture of the framework and highlight key implementation details. Finally, we provide illustrative examples of stochastic programming functionality and benchmarks on large-scale problems.

Then, we pursue further algorithmic improvements to the distributed L-shaped algorithm. Specifically, we consider the use of dynamic cut aggregation. We develop theoretical results on convergence and complexity and then showcase performance improvements in numerical experiments. We suggest several aggregation schemes that are based on parameterized selection rules. Before we perform large-scale experiments, the aggregation parameters are determined by a tuning procedure. In brief, cut aggregation can yield major performance improvements to L-shaped algorithms in distributed settings.

Finally, we consider an application to hydropower operations. The day-ahead planning problem involves specifying optimal order volumes in a deregulated electricity market, without knowledge of the next-day market price, and then optimizing the hydropower production. We provide a detailed introduction to the day-ahead model and explain how we can implement it with our computational tools. This covers a complete procedure of gathering data, generating forecasts from the data, and finally formulating and solving a stochastic programming model of the day-ahead problem. Using a sample-based algorithm that internally relies on our structure-exploiting solvers, we obtain tight confidence intervals around the optimal solution of the day-ahead problem.

• 13.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
POLO.Jl: Policy-based optimization algorithms in Julia2019In: Advances in Engineering Software, ISSN 0965-9978, E-ISSN 1873-5339, Vol. 136, article id 102695Article in journal (Refereed)

We present POLO. j1- a Julia package that helps algorithm developers and machine-learning practitioners design and use state-of-the-art parallel optimization algorithms in a flexible and efficient way. POLO. j1 extends our C+ + library POLO, which has been designed and implemented with the same intentions. POLO. j1 not only wraps selected algorithms in POLO and provides an easy mechanism to use data manipulation facilities and loss function definitions in Julia together with the underlying compiled C+ + library, but it also uses the policy-based design technique in a Julian way to help users prototype optimization algorithms from their own building blocks. In our experiments, we observe that there is little overhead when using the compiled C+ + code directly within Julia. We also notice that the performance of algorithms implemented in pure Julia is comparable with that of their C+ + counterparts. Both libraries are hosted on GitHub(1)under the free MIT license, and can be used easily by pulling the pre-built 64-bit architecture Docker images.(2)

• 14.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. ABB, Corp Res, Vasteras, Sweden.. Svenska kraftnat, R&D, Sundbyberg, Sweden..
Analysis of Coordinated HVDC Control for Power Oscillation Damping2018In: Conference Record of the 3rd IEEE International Workshop on Electronic Power Grid, eGrid 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 19-24, article id 8598674Conference paper (Refereed)

Controlling the active power of high-voltage de (HVDC) transmission that interconnects two asynchronous ac grids can be used to improve the power oscillation damping in both of the interconnected ac systems. Using one HVDC link, achievable performance are limited since control actions may excite modes of similar frequencies in the assisting network. However, with coordinated control of two or more HVDC links, the limitations can be circumvented. With decoupling control the system interactions can be avoided all together. This paper investigates the conditions suitable for decoupling control. It is also shown that decoupling between system modes can be achieved using a proportional controller. The control method is compared to decentralized and H-2 optimal control. The best control method for different system topologies is investigated by looking on input usage and stability following dc link failure.

• 15.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). Uppsala Univ, Dept Engn Sci, Uppsala, Sweden..
A Tutorial Introduction to Security and Privacy for Cyber-Physical Systems2019In: Proceedings 2019 18th European Control Conference (ECC), IEEE , 2019, p. 968-978Conference paper (Refereed)

This tutorial provides a high-level introduction to novel control-theoretic approaches for the security and privacy of cyber-physical systems (CPS). It takes a risk-based approach to the problem and develops a model framework that allows us to introduce and relate many of the recent contributions to the area. In particular, we explore the concept of risk in the context of CPS under cyber-attacks, paying special attention to the characterization of attack scenarios and to the interpretation of impact and likelihood for CPS. The risk management framework is then used to give an overview of and map different contributions in the area to three core parts of the framework: attack scenario description, quantification of impact and likelihood, and mitigation strategies. The overview is by no means complete, but it illustrates the breadth of the problems considered and the control-theoretic solutions proposed so far.

• 16.
MIT, Dept Mech Engn, Cambridge, MA 02139 USA..
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. MIT, Dept Mech Engn, Cambridge, MA 02139 USA.. KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. North Carolina State Univ, Dept Elect Engn, Raleigh, NC USA..
Secure Control of Wide-Area Power Systems: Confidentiality and Integrity Threats2018In: 2018 IEEE Conference on Decision and Control  (CDC), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 7269-7274, article id 8618862Conference paper (Refereed)

A cyber-physical model for wide-area control of power systems is considered, where the state variables of each generator are measured and sent to the cyber-network and the corresponding control inputs are computed distributively. The secure control of such wide-area power systems is considered in the presence of cyber attacks that introduce threats that compromise their integrity and confidentiality. Detection, prevention, and resilience for these attacks and algorithms for accomplishing these goals are proposed. In particular, an algorithm to overcome confidentiality attacks of the underlying control gains is presented. Also proposed is an algorithm for defense against integrity attacks that might take place on the cyber-network. For this purpose, a resilient information retrieval approach is leveraged which recovers the true state variables despite the malicious attacks on both virtual machines and communication links. The retrieved states are then used to detect possible attacks on phasor measurement units (PMU) in the next time-step. Simulation studies are included to validate our proposed approaches.

• 17.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems.
MEMS for Photonic Integrated Circuits2020In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 26, no 2, p. 1-16Article in journal (Refereed)

The field of microelectromechanical systems (MEMS) for photonic integrated circuits (PICs) is reviewed. This field leverages mechanics at the nanometer to micrometer scale to improve existing components and introduce novel functionalities in PICs. This review covers the MEMS actuation principles and the mechanical tuning mechanisms for integrated photonics. The state of the art of MEMS tunable components in PICs is quantitatively reviewed and critically assessed with respect to suitability for large-scale integration in existing PIC technology platforms. MEMS provide a powerful approach to overcome current limitations in PIC technologies and to enable a new design dimension with a wide range of applications.

• 18.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems.
Scania Technical Centre. KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Integrated devices and circuits. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems. AMO GmbH. KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Integrated devices and circuits. KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Integrated devices and circuits. RWTH Aachen University; AMO GmbH. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems.
Suspended Graphene Membranes with Attached Silicon Proof Masses as Piezoresistive Nanoelectromechanical Systems Accelerometers2019In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, no 10, p. 6788-6799Article in journal (Refereed)

Graphene is an atomically thin material that features unique electrical and mechanical properties, which makes it an extremely promising material for future nanoelectromechanical systems (NEMS). Recently, basic NEMS accelerometer functionality has been demonstrated by utilizing piezoresistive graphene ribbons with suspended silicon proof masses. However, the proposed graphene ribbons have limitations regarding mechanical robustness, manufacturing yield, and the maximum measurement current that can be applied across the ribbons. Here, we report on suspended graphene membranes that are fully clamped at their circumference and have attached silicon proof masses. We demonstrate their utility as piezoresistive NEMS accelerometers, and they are found to be more robust, have longer life span and higher manufacturing yield, can withstand higher measurement currents, and are able to suspend larger silicon proof masses, as compared to the previous graphene ribbon devices. These findings are an important step toward bringing ultraminiaturized piezoresistive graphene NEMS closer toward deployment in emerging applications such as in wearable electronics, biomedical implants, and internet of things (IoT) devices.

• 19.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Information Science and Engineering.
Stanford University.
Systems, methods, devices and arrangements for motion-compensated image processing and coding2007Patent (Other (popular science, discussion, etc.))
• 20.
Ericsson.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering. Ericsson. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Information Science and Engineering.
Methods and arrangements for 3D scene representation2010Patent (Other (popular science, discussion, etc.))
• 21.
Saab AB, SE-581 88 Linköping, Sweden ; Department of Electrical and Information Technology, Lund University.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Robotics, Perception and Learning, RPL. Saab AB, SE-581 88 Linköping, Sweden. Saab AB, SE-581 88 Linköping, Sweden ; Department of Electrical and Information Technology, Lund University.
Enhanced sonar image resolution using compressive sensing modelling2019In: Conference Proceedings 5th Underwater Acoustics Conference and Exhibition UACE2019 / [ed] John S. Papadakis, UACE , 2019, p. 995-999Conference paper (Other academic)

The sonar image resolution is classically limited by the sonar array dimensions. There are several techniques to enhance the resolution; most common is the synthetic aperture sonar (SAS) technique where several pings are added coherently to achieve a longer array and thereby higher cross range resolution. This leads to high requirements on navigation accuracy, but the different autofocus techniques in general also require collecting overlapping data. This limits the acquisition speed whencovering a specific area. We investigate the possibility to enhance the resolution in images processed from one ping measurementin this paperusing compressive sensing methods. A model consisting of isotropic point scatterers is used for the imaged target. The point scatterer amplitudes are frequency and angle independent. We assume only direct paths between the scatterers and the transmitter/receiver in theinverse problemformulation. The solution to this system of equations turns out to be naturally sparse, i.e., relatively few scatterers are required to describe the measured signal.The sparsity means that L1 optimization and methods from compressive sensing (CS) can be used to solve the inverse problem efficiently. We use the basis pursuit denoise algorithm (BPDN) as implemented in the SPGL1 package to solve the optimization problem.We present results based on CS on measurements collected at Saab. The measurements are collected using the experimental platform Sapphires in freshwater Lake Vättern. Images processed using classical back projection algorithms are compared tosonar images with enhanced resolution using CS, with a 10 times improvement in cross range resolution.

• 22.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Robotics, Perception and Learning, RPL.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Robotics, Perception and Learning, RPL. KTH. KTH. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Robotics, Perception and Learning, RPL.
Placing Objects with prior In-Hand Manipulation using Dexterous Manipulation Graphs2019Conference paper (Refereed)

We address the problem of planning the placement of a grasped object with a robot manipulator. More specifically, the robot is tasked to place the grasped object such that a placement preference function is maximized. For this, we present an approach that uses in-hand manipulation to adjust the robot’s initial grasp to extend the set of reachable placements. Given an initial grasp, the algorithm computes a set of grasps that can be reached by pushing and rotating the object in-hand. With this set of reachable grasps, it then searches for a stable placement that maximizes the preference function. If successful it returns a sequence of in-hand pushes to adjust the initial grasp to a more advantageous grasp together with a transport motion that carries the object to the placement. We evaluate our algorithm’s performance on various placing scenarios, and observe its effectiveness also in challenging scenes containing many obstacles. Our experiments demonstrate that re-grasping with in-hand manipulation increases the quality of placements the robot can reach. In particular, it enables the algorithm to find solutions in situations where safe placing with the initial grasp wouldn’t be possible.

• 23.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
Event-triggered Feedforward Control subject to Actuator Saturation for Disturbance Compensation∗2018In: 2018 European Control Conference, ECC 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 501-506, article id 8550115Conference paper (Refereed)

Feedfoward control is widely used to compensate measurable external disturbances. This paper studies feedforward control using an event-triggered sensor. Stability conditions when the feedback control is subject to actuator saturation are derived. We also obtain stability conditions of eventtriggered feedforward control with anti-windup compensation. A numerical example shows that event-triggered feedforward control significantly reduces communication between the sensor and the controller without performance degradation compared with continuous-time feedforward control.

• 24.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Stochastic phase-cohesiveness of discrete-time Kuramoto oscillators in a frequency-dependent tree network2019In: Proceedings 2019 18th European Control Conference (ECC), IEEE , 2019, p. 1987-1992Conference paper (Refereed)

This paper presents the notion of stochastic phase-cohesiveness based on the concept of recurrent Markov chains and studies the conditions under which a discrete-time stochastic Kuramoto model is phase-cohesive. It is assumed that the exogenous frequencies of the oscillators are combined with random variables representing uncertainties. A bidirectional tree network is considered such that each oscillator is coupled to its neighbors with a coupling law which depends on its own noisy exogenous frequency. In addition, an undirected tree network is studied. For both cases, a sufficient condition for the common coupling strength (kappa) and a necessary condition for the sampling-period are derived such that the stochastic phase-cohesiveness is achieved. The analysis is performed within the stochastic systems framework and validated by means of numerical simulations.

• 25.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL. KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
A hierarchical control system for smart parking lots with automated vehicles: Improve efficiency by leveraging prediction of human drivers2019In: Proceedings 2019 18TH EUROPEAN CONTROL CONFERENCE (ECC), IEEE , 2019, p. 2675-2681Conference paper (Refereed)

In this work, we introduce a hierarchical architecture for management of multiple automated vehicles in a parking lot provided the existence of human-driven vehicles. The proposed architecture consists of three layers: behavior prediction, vehicle coordination and maneuver control, with the first two sitting in the infrastructure and the third one equipped on individual vehicles. We assume all three layers share a consistent view of the environment by considering it as a grid world. The grid occupancy is modeled by the prediction layer via collecting information from automated vehicles and predicting human-driven vehicles. The coordination layer assigns parking spots and grants permissions for vehicles to move. The vehicle control embraces the distributed model predictive control (MPC) technique to resolve local conflicts occurred due to the simplified vehicle models used in the design of the prediction and coordination layers. Numerical evaluation shows the effectiveness of the proposed control system.

• 26.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Automat Control, S-10044 Stockholm, Sweden..
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Decentralized Control Barrier Functions for Coupled Multi-Agent Systems under Signal Temporal Logic Tasks2019In: Proceedings 2019 18th European Control Conference (ECC), IEEE , 2019, p. 89-94Conference paper (Refereed)

We study the problem of controlling multi-agent systems under a set of signal temporal logic tasks. Signal temporal logic is a formalism that is used to express time and space constraints for dynamical systems. Recent methods to solve the control synthesis problem for single-agent systems under signal temporal logic tasks are, however, subject to a high computational complexity. Methods for multi-agent systems scale at least linearly with the number of agents and induce even higher computational burdens. We propose a computationally-efficient control strategy to solve the multi-agent control synthesis problem that results in a robust satisfaction of a set of signal temporal logic tasks. In particular, a decentralized feedback control law is proposed that is based on time-varying control barrier functions. The obtained control law is discontinuous and formal guarantees are provided by nonsmooth analysis. Simulations show the efficacy of the presented method.

• 27.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Speech, Music and Hearing, TMH, Music Acoustics.
Flow ball-assisted training: immediate effects on vocal fold contacting2019In: Pan-European Voice Conference 2019 / [ed] Jenny Iwarsson, Stine Løvind Thorsen, University of Copenhagen , 2019, p. 50-51Conference paper (Refereed)

Background: The flow ball is a device that creates a static backpressure in the vocal tract while providing real-time visual feedback of airflow. A ball height of 0 to 10 cm corresponds to airflows of 0.2 to 0.4. L/s. These high airflows with low transglottal pressure correspond to low flow resistances, similar to the ones obtained when phonating into straws with 3.7 mm diameter and of 2.8 cm length. Objectives: To investigate whether there are immediate effects of flow ball-assisted training on vocal fold contact. Methods: Ten singers (five males and five females) performed a messa di voce at different pitches over one octave in three different conditions: before, during and after phonating with a flow ball. For all conditions, both audio and electrolaryngographic (ELG) signals were simultaneously recorded using a Laryngograph microprocessor. The vocal fold contact quotient Qci (the area under the normalized EGG cycle) and dEGGmaxN (the normalized maximum rate of change of vocal fold contact area) were obtained for all EGG cycles, using the FonaDyn system. We introduce also a compound metric Ic ,the âindex of contact’ [Qci Ã log10(dEGGmaxN)], with the properties that it goes to zero at no contact. It combines information from both Qci and dEGGmaxN and thus it is comparable across subjects. The intra-subject means of all three metrics were computed and visualized by colour-coding over the fo-SPL plane, in cells of 1 semitone Ã 1 dB. Results: Overall, the use of flow ball-assisted phonation had a small yet significant effect on overall vocal fold contact across the whole messa di voce exercise. Larger effects were evident locally, i.e., in parts of the voice range. Comparing the pre-post flow-ball conditions, there were differences in Qci and/or dEGGmaxN. These differences were generally larger in male than in female voices. Ic typically decreased after flow ball use, for males but not for females. Conclusion: Flow ball-assisted training seems to modify vocal fold contacting gestures, especially in male singers.

• 28. Malisz, Zofia
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH.
Modern speech synthesis for phonetic sciences: A discussion and an evaluation2019In: Proceedings of ICPhS, 2019Conference paper (Refereed)
• 29.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. Tech Univ Munich, Chair Informat Oriented Control, Munich, Germany..
State-dependent Data Queuing in Shared-resource Networked Control Systems2018In: 2018 IEEE Conference on Decision and Control (CDC), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1731-1737, article id 8619752Conference paper (Refereed)

In the design of shared resource networked control systems (NCSs), resource managers play an important role to appropriately allocate limited resources across the distributed system. They are often used to fairly distribute the limited bandwidth among the medium-sharing entities at the expense of delaying or discarding unnecessary data samples. Considering the rapidly growing volume of information being exchanged, a relevant scenario for efficient resource management is state-dependent data buffering via network queues. In this paper, we propose state-dependent data buffering for shared-resource NCSs, such that the buffer state, i.e. queue length, can be controlled depending on the real-time conditions of both the control systems and the communication network. We consider that the transmission decisions at the sensor sides are taken by event-based schedulers, and those data eventually sent for transmission are queued and processed depending on the available communication resource. We derive sufficient conditions under which the NCS with the proposed cross-layer transmission scheme is stable in almost sure mean-square sense. Moreover, we show performance improvements resulting from our proposed design in comparison with its state-independent counterpart.

• 30.
McGill Univ, Dept Elect & Comp Engn, Montreal, PQ, Canada..
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre. McGill Univ, Dept Elect & Comp Engn, Montreal, PQ, Canada..
Optimal sampling of multiple linear processes over a shared medium2018In: 2018 IEEE Conference on Decision and Control (CDC), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1712-1718Conference paper (Refereed)

In many emerging applications, multiple sensors transmit their measurements to a remote estimator over a shared medium. In such a system, the optimal sampling rates at each sensor depend on the nature of the stochastic process being observed as well as the available communication capacity. Our main contribution is to show that the problem of determining optimal sampling rates may be posed as a network utility maximization problem and solved using appropriate modifications of the standard dual decomposition algorithms for network utility maximization. We present two such algorithms, one synchronous and one asynchronous, and show that under mild technical conditions, both algorithms converge to the optimal rate allocation. We present a detailed simulation study to illustrate that the asynchronous algorithm is able to adapt the sampling rate to change in the number of sensors and the available channel capacity and is robust to packet drops.

• 31.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
Quantifying the Impact of Cyber-Attack Strategies for Control Systems Equipped with an Anomaly Detector2018In: 2018 European Control Conference, ECC 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 331-337, article id 8550188Conference paper (Refereed)

Risk assessment is an inevitable step in the implementation of cost-effective security strategies for control systems. One of the difficulties of risk assessment is to estimate the impact cyber-attacks may have. This paper proposes a framework to estimate the impact of several cyber-attack strategies against a dynamical control system equipped with an anomaly detector. In particular, we consider denial of service, sign alternation, rerouting, replay, false data injection, and bias injection attack strategies. The anomaly detectors we consider are stateless, cumulative sum, and multivariate exponentially weighted moving average detectors. As a measure of the attack impact, we adopt the infinity norm of critical states after a fixed number of time steps. For this measure and the aforementioned anomaly detectors, we prove that the attack impact for all of the attack strategies can be reduced to the problem of solving a set of convex minimization problems. Therefore, the exact value of the attack impact can be obtained easily. We demonstrate how our modeling framework can be used for risk assessment on a numerical example.

• 32.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Risk-Coherent H-optimal Filter Design Under Model Uncertainty with Applications to MISO Control2019In: 2019 18th European Control Conference, ECC 2019, Institute of Electrical and Electronics Engineers (IEEE), 2019, p. 1461-1466, article id 8795947Conference paper (Refereed)

This work presents a framework to address the problem of designing discrete-time LTI (linear and time-invariant) multiple-input and multiple-output (MIMO) filters, aiming to optimize the performance of a system when model uncertainty is considered. Additionally, we present an interesting application to control design for disturbance rejection under model uncertainty. To account for this uncertainty we employ coherent measures of risk, which are a family of measures in theory of risk. We particularly discuss which measures are suitable by comparing the conditional value-at-risk (CVaR) to other three common designs. Using a scenario approach, we derive a convex optimization problem based on linear matrix inequalities (LMIs), whose solution minimizes the risk of falling into poor mathcal{H}{ infty} performance. Finally, we present an application to multiple-input and single-output (MISO) control design under model uncertainty in the auto-covariance function of the output noise, comparing approaches minimizing different notions of risk.

• 33.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Robust and Decentralized Control of Multi-agent Systems under High-level Tasks2019Doctoral thesis, monograph (Other academic)

Decentralized control of multi-agent systems is an active topic of research, with many practical applications arising in multi-robot systems, autonomous driving, transportation systems and robotic manipulation. The contributions of this thesis lie in the scope of three topics: formation control, robust decentralized tube-based nonlinear Model Predictive Control and time-constrained cooperative planning of multi-agent systems.

In the first part of the thesis, given a team of rigid bodies, we propose model-free and decentralized control protocols such that a desired distance and orientationbased formation between neighboring agents is achieved. Inter-agent collisions are guaranteed to be avoided by the proposed control scheme. Furthermore, the connectivity between agents that are initially connected is preserved. The transient and steady state responses are solely determined by certain designer-specified performance functions.

In the second part of the thesis, the problem of robust navigation of a multi-agent system to predefined states of the workspace while using only local information is addressed, under certain distance and control input constraints. The agents are modeled by nonlinear continuous-time dynamics with additive and bounded disturbances. In order to address this problem, decentralized tube-based nonlinear Model Predictive Control protocols are proposed. In particular, the feedback control law contains a portion that is calculated offline and a portion which is the outcome of an online optimal control problem.

In the third part of the thesis, a team of agents operating in a bounded workspace is considered. Each agent is assigned with high-level tasks given in Metric Interval Temporal Logic. First, by providing novel decentralized abstraction design techniques, the motion of each agent is captured through a weighted transition system. Then, we propose decentralized control methodologies and high-level algorithms that guarantee the satisfaction of the desired tasks of each agent. The proposed approach can handle couplings as well as transient constraints of each agent in a novel way.

• 34.
KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
Estimation of the Clipping Level in OFDM Systems2015Conference paper (Refereed)
• 35.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems. Senseair AB, Stn Gatan 12, S-82471 Delsbo, Sweden.. Senseair AB, Stn Gatan 12, S-82471 Delsbo, Sweden.. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems.
Carbon Dioxide Sensing with Low-confinement High-sensitivity Mid-IR Silicon Waveguides2019In: 2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), Institute of Electrical and Electronics Engineers (IEEE), 2019, article id 8750210Conference paper (Refereed)

We present a low-confinement Si waveguide for 4.26 μm wavelength and apply it to sense CO2 concentrations down to 0.1 %. We demonstrate the highest reported waveguide sensitivity to CO2: 44 % of the free-space sensitivity.

• 36.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Information Science and Engineering.
University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Information Science and Engineering.
Distributed Detection with Non-identical Wireless Sensors for Industrial Applications2019In: 2019 IEEE International Conference on Industrial Technology (ICIT), IEEE, 2019, p. 1403-1408Conference paper (Refereed)

There has been very little exploration when it comes to design distributed detection techniques and data fusion rules with non-identical sensors. This concept can be utilized in many possible applications within industrial automation, surveillance and safety. Here, for a global event, some of the sensors/detectors in the network can observe the full set of the hypotheses, whereas the remaining sensors infer more than one hypotheses as a single hypothesis. The local decisions are sent to the decision fusion center (DFC) over a multiple access wireless channel. In this paper, a fusion rule based on minimization of variance of the local mis-detection is proposed. The presence of sensors with limited detection capabilities is found to have a positive impact on the overall system performance, both in terms of probability of detection and transmit power consumption. Additionally, when the DFC is equipped with a large antenna array,the overall transmit power consumption can be reduced without sacrificing the detection performance.

• 37.
Univ Pavia, Dept Elect Comp & Biomed Engn, Pavia, Italy..
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Decision and Control Systems (Automatic Control). Univ Pavia, Dept Elect Comp & Biomed Engn, Pavia, Italy.. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Decision and Control Systems (Automatic Control).
VACS equipped vehicles for congestion dissipation in multi-class CTM framework2019In: 2019 18TH EUROPEAN CONTROL CONFERENCE (ECC), IEEE , 2019, p. 2203-2208Conference paper (Refereed)

The advent of connected, automated and autonomous vehicles introduces the possibility for new traffic control approaches. Vehicles equipped with automation and communication systems can be exploited both as sensor and actuators for traffic control actions, thus avoiding the need for new infrastructure. In this paper a multi-class extension of the macroscopic Cell Transmission Model is adopted to describe the interaction between different classes of vehicles, for example human-driven and connected/automated. The vehicle classes are distinguished on the basis of their time headways and their speed. By means of a Model Predictive Control approach, the optimal free-flow speed for the class of connected/automated vehicles is computed and applied to them with the aim of reducing congestion on the highway. The effectiveness of the proposed control law is analyzed depending on the penetration rate of controlled vehicles and the approach is assessed in simulations.

• 38.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). MIT, Dept Mech Engn, Cambridge, MA 02139 USA.. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control). KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Design of Attack-Resilient Consensus Dynamics: A Game-Theoretic Approach2019In: Proceedings 2019 18th European Control Conference (ECC), IEEE , 2019, p. 2227-2232Conference paper (Refereed)

We propose a game-theoretic framework for improving the resilience of multi-agent consensus dynamics in the presence of a strategic attacker. In this game, the attacker selects a set of network nodes to inject the attack signals. The attacker's objective is to minimize the required energy for steering the consensus towards its desired direction. This energy is captured by the trace of controllability Gramian of the system when the input is the attack signal. The defender improves the resilience of dynamics by adding self-feedback loops to certain nodes of the system and its objective is to maximize the trace of controllability Gramian. The Stackelberg equilibrium of the game is studied with the defender as the game leader. When the underlying network topology is a tree and the defender can select only one node, we show that the optimal strategy of the defender is determined by a specific distance-based network centrality measure, called network's f-center. In addition, we show that the degree-based centralities solutions may lead to undesirable payoffs for the defender. At the end, we discuss the case of multiple attack and defense nodes on general graphs.

• 39. Quack, Niels
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems. KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Micro and Nanosystems.
Exploiting Mechanics at the Nanoscale to Enhance Photonic Integrated Circuits2019Conference paper (Other academic)

With the maturing and the increasing complexity of Silicon Photonics technology, novel avenues are pursued to reduce power consumption and to provide enhanced functionality: exploiting mechanical movement in advanced Silicon Photonic Integrated Circuits provides a promising path to access a strong modulation of the effective index and to low power consumption by employing mechanically stable and thus non-volatile states. In this paper, we will discuss recent achievements in the development of MEMS enabled systems in Silicon Photonics and outline the roadmap towards reconfigurable general Photonic Integrated Circuits.

• 40.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Logarithmic Quantization based Symbolic Abstractions for Nonlinear Control Systems2019In: Proceedings 2019 18th European Control Conference (ECC), IEEE , 2019, p. 1312-1317Conference paper (Refereed)

This paper studies symbolic abstractions for nonlinear control systems using logarithmic quantization. With a logarithmic quantizer, we approximate the state and input sets, and then construct a novel discrete abstraction for nonlinear control systems. A feedback refinement relation between the constructed discrete abstraction and the original system is established. Using the constructed discrete abstraction, the safety controller synthesis problem is studied. With the discrete abstraction and the abstract specification, the existence of a safety controller is investigated, and the algorithm is proposed to compute the abstract controller. Finally, a numerical example is given to illustrate the obtained results.

• 41. Ren, Xiaoqiang
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
Infinite Horizon Optimal Transmission Power Control for Remote State Estimation Over Fading Channels2018In: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 63, no 1, p. 85-100Article in journal (Refereed)

This paper studies the joint design over an infinite horizon of the transmission power controller and remote estimator for state estimation over fading channels. A sensor observes a dynamic process and sends its observations to a remote estimator over a wireless fading channel characterized by a time-homogeneous Markov chain. The successful transmission probability depends on both the channel gains and the transmission power used by the sensor. The transmission power control rule and the remote estimator should be jointly designed, aiming to minimize an infinite-horizon cost consisting of the power usage and the remote estimation error. We formulate the joint optimization problem as an average cost belief-state Markov decision process and prove that there exists an optimal deterministic and stationary policy. We then show that when the monitored dynamic process is scalar or the system matrix is orthogonal, the optimal remote estimates depend only on the most recently received sensor observation, and the optimal transmission power is symmetric and monotonically increasing with respect to the norm of the innovation error.

• 42.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
Vertical Integration of Microchips by Magnetic Assembly and Edge Wire BondingIn: Article in journal (Refereed)
• 43.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Robotics, Perception and Learning, RPL. Saab, SE-581 88 Linköping, Sweden.
Saab, SE-581 88 Linköping, Sweden;Department of Electrical and Information Technology, Lund University. Saab, SE-581 88 Linköping, Sweden;Department of Electrical and Information Technology, Lund University.
Deep learning based technique for enhanced sonar imaging2019Conference paper (Other academic)

Several beamforming techniques can be used to enhance the resolution of sonar images. Beamforming techniques can be divided into two types: data independent beamforming such as the delay-sum-beamformer, and data-dependent methods known as adaptive beamformers. Adaptive beamformers can often achieve higher resolution, but are more sensitive to errors. Several signals are processed from several consecutive pings. The signals are added coherently to achieve the same effect as having a longer array in synthetic aperture sonar (SAS). In general it can be said that a longer array gives a higher image resolution. SAS processing typically requires high navigation accuracy, and physical array-overlap between pings. This restriction on displacement between pings limits the area coverage rate for the vehicle carrying the SAS. We investigate the possibility to enhance sonar images from one ping measurements in this paper. This is done by using state-of-the art techniques from Image-to-Image translation, namely the conditional generative adversarial network (cGAN) Pix2Pix. The cGAN learns a mapping from an input to output image as well as a loss function to train the mapping. We test our concept by training a cGAN on simulated data, going from a short array (low resolution) to a longer array (high resolution). The method is evaluated using measured SAS-data collected by Saab with the experimental platform Sapphires in freshwater Lake Vättern.

• 44.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligenta system, Decision and Control Systems (Automatic Control).
Oliver Wyman Inc, Toronto, ON M5J 0A1, Canada.. Bilkent Univ, Dept Elect & Elect Engn, TR-06800 Ankara, Turkey.. Queens Univ, Dept Math & Stat, Kingston, ON K7L 3N6, Canada.. Queens Univ, Dept Math & Stat, Kingston, ON K7L 3N6, Canada..
On the Number of Bins in Equilibria for Signaling Games2019In: 2019 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY (ISIT), IEEE , 2019, p. 972-976Conference paper (Refereed)

We investigate the equilibrium behavior for the decentralized quadratic cheap talk problem in which an encoder and a decoder, viewed as two decision makers, have misaligned objective functions. In prior work, we have shown that the number of bins under any equilibrium has to be at most countable, generalizing a classical result due to Crawford and Sobel who considered sources with density supported on [0, 1]. In this paper, we refine this result in the context of exponential and Gaussian sources. For exponential sources, a relation between the upper bound on the number of bins and the misalignment in the objective functions is derived, the equilibrium costs are compared, and it is shown that there also exist equilibria with infinitely many bins under certain parametric assumptions. For Gaussian sources, it is shown that there exist equilibria with infinitely many bins.

• 45.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA.. Stanford Univ, Dept Comp Sci, Stanford, CA 94305 USA.. Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA.. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
Human-robot interaction for truck platooning using hierarchical dynamic games2019In: Proceedings 2019 18TH EUROPEAN CONTROL CONFERENCE (ECC), IEEE , 2019, p. 3165-3172Conference paper (Refereed)

This paper proposes a controller design framework for autonomous truck platoons to ensure safe interaction with a human-driven car. The interaction is modelled as a hierarchical dynamic game, played between the human driver and the nearest truck in the platoon. The hierarchical decomposition is temporal with a high-fidelity tactical horizon predicting immediate interactions and a low-fidelity strategic horizon estimating long-horizon behaviour. The hierarchical approach enables feasible computations where human uncertainties are represented by the quantal response model, and the truck is supposed to maximise its payoff. The closed-loop control is validated via case studies using a driving simulator, where we compare our approach with a short-horizon alternative using only the tactical horizon. The results indicate that our controller is more situation-aware resulting in natural and safe interactions.

• 46.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH. University College of Music Education Stockholm.
The Singing Voice2019In: The Oxcford Handbook of Voice Perception / [ed] S Früholz and P Belin, Oxford: Oxford University Press, 2019, 1, p. 117-142Chapter in book (Refereed)

The sound quality of singing is determined by three basic factors—the air pressure under the vocal folds (or the subglottal pressure), the mechanical properties of the vocal folds, and the resonance properties of the vocal tract. Subglottal pressure is controlled by the respiratory apparatus. It regulates vocal loudness and is varied with pitch in singing. Together with the mechanical properties of the folds, which are controlled by laryngeal muscles, it has a decisive influence on vocal fold vibrationswhich convert the tracheal airstream to a pulsating airflow, the voice source. The voice source determines pitch, vibrato, and register, and also the overall slope of the spectrum. The sound of the voice source is filtered by the resonances of the vocal tract, or the formants, of which the two lowest determine the vowel quality and the higher ones the personal voice quality. Timing is crucial for creating emotional expressivity; it uses an acoustic code that shows striking similarities to that used in speech. The perceived loudness of a vowel sound seems more closely related to the subglottal pressure with which it was produced than with the acoustical sound level. Some investigations of acoustical correlates of tone placement and variation of larynx height are described, as are properties that affect the perceived naturalness of synthesized singing. Finally, subglottal pressure, voice source, and formant-frequency characteristics of some non-classical styles of singing are discussed.

• 47.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH. University College of Music Education Stockholm.
Analyzing Emotion Expression in Singing via Flow Glottograms, Long-Term-Average Spectra, and Expert Listener Evaluation2019In: Journal of Voice, ISSN 0892-1997, E-ISSN 1873-4588Article in journal (Refereed)

Acoustic aspects of emotional expressivity in speech have been analyzed extensively during recent decades. Emotional coloring is an important if not the most important property of sung performance, and therefore strictly controlled. Hence, emotional expressivity in singing may promote a deeper insight into vocal signaling of emotions. Furthermore, physiological voice source parameters can be assumed to facilitate the understanding of acoustical characteristics.

Method

Three highly experienced professional male singers sang scales on the vowel /ae/ or /a/ in 10 emotional colors (Neutral, Sadness, Tender, Calm, Joy, Contempt, Fear, Pride, Love, Arousal, and Anger). Sixteen voice experts classified the scales in a forced-choice listening test, and the result was compared with long-term-average spectrum (LTAS) parameters and with voice source parameters, derived from flow glottograms (FLOGG) that were obtained from inverse filtering the audio signal.

Results

On the basis of component analysis, the emotions could be grouped into four “families”, Anger-Contempt, Joy-Love-Pride, Calm-Tender-Neutral and Sad-Fear. Recognition of the intended emotion families by listeners reached accuracy levels far beyond chance level. For the LTAS and FLOGG parameters, vocal loudness had a paramount influence on all. Also after partialing out this factor, some significant correlations were found between FLOGG and LTAS parameters. These parameters could be sorted into groups that were associated with the emotion families.

Conclusions

(i) Both LTAS and FLOGG parameters varied significantly with the enactment intentions of the singers. (ii) Some aspects of the voice source are reflected in LTAS parameters. (iii) LTAS parameters affect listener judgment of the enacted emotions and the accuracy of the intended emotional coloring.

• 48.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH.
Off the cuff: Exploring extemporaneous speech delivery with TTS2019Conference paper (Refereed)
• 49.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH.
KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Speech, Music and Hearing, TMH.
Spontaneous conversational speech synthesis from found data2019Conference paper (Refereed)
• 50.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
Fuel-Efficient En Route Formation of Truck Platoons2018In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 19, no 1, p. 102-112Article in journal (Refereed)

The problem of how to coordinate a large fleet of trucks with a given itinerary to enable fuel-efficient platooning is considered. Platooning is a promising technology that enables trucks to save significant amounts of fuel by driving close together and thus reducing air drag. A setting is considered in which each truck in a fleet is provided with a start location, a destination, a departure time, and an arrival deadline from a higher planning level. Fuel-efficient plans should be computed. The plans consist of routes and speed profiles that allow trucks to arrive by their arrival deadlines. Hereby, trucks can meet on common parts of their routes and form platoons, resulting in decreased fuel consumption. We formulate a combinatorial optimization problem that combines plans involving only two vehicles. We show that this problem is difficult to solve for large problem instances. Hence, a heuristic algorithm is proposed. The resulting plans are further optimized using convex optimization techniques. The method is evaluated with Monte Carlo simulations in a realistic setting. We demonstrate that the proposed algorithm can compute plans for thousands of trucks and that significant fuel savings can be achieved.

12 1 - 50 of 62
Cite
Citation style
• apa
• harvard1
• ieee
• modern-language-association-8th-edition
• vancouver
• Other style
More styles
Language
• de-DE
• en-GB
• en-US
• fi-FI
• nn-NO
• nn-NB
• sv-SE
• Other locale
More languages
Output format
• html
• text
• asciidoc
• rtf