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In this paper the general subject area is the stability of multidimensional linear systems. The basis is the theory of a nonnegative shift operator acting on the space of continuous bounded functions given on a locally compact group. Some spectral properties of this shift operator are established and applied to obtain new results on the stability of a class of linear multidimensional discrete systems.
We study polynomially nonlinear, continuous Roesser models. First we characterize when a variety V is invariant for an autonomous system. Then we derive conditions to decide whether V is controlled invariant, i.e., whether it can be made invariant through polynomial state feedback.
Two-dimensional zero-attraction projection (2DZAP) algorithm for single snapshot direction of arrival (DOA) estimation is proposed in this paper. Compared with the traditional DOA estimation, the proposed 2D-ZAP algorithm can estimate DOA exactly by ℓ-norm with the same number of sensors, although each sensor samples the signal only one time. In addition, 2D-ZAP algorithm can reduce the noise interference...
Nowadays, human activity recognition with wearables is an interesting field, but the accurate assessment of activity remains a challenging problem because of the different behaviour in which the activities are performed of different persons. In this paper machine learning with support vector machines in combination with an Inertial Measurement Unit (IMU) is used to determine the different kinds of...
This paper proposes a new order reduction approach for multidimensional (n-D) Roesser state-space model. The proposed approach is based on a certain system of equations which can be constructed from the well defined initial matrix constructed by the coefficient matrices of the given n-D Roesser state-space model. If there is a nonzero solution of the constructed certain system of equations, then the...
Our aim is to use randomly generated image transformation in order to obtain image features of low dimensionality. The transformation consists of local projections of spatiallyorganized parts of an image, for example rectangular image blocks. After this transformation the content of an image is hidden and will not be stably recoverable, so it can be used in systems where privacy-preserving property...
This paper continues the development of an iterative learning control law for a class of spatially distributed systems based on the particular case of a circular deformable mirror. This system is described by a fourth-order partial differential equation but in many cases the design and implementation of control laws is based on a discrete model. In this paper, an unconditionally stable finite difference...
The wave digital filter approach, introduced in 1986 by G. Fettweis, is a very advantagous approach for realization of digital filters, especially in higher dimensional cases, like image- and video-processing applications. If properly followed, it guarantees a stable system realization and low sensitivity to quantization errors, which is crucial for implementations on fixed point hardware. While these...
This paper describes recent work on the topic of multi-dimensional (MD) spatio-temporal noise and distortion shaping for radio-frequency (RF) antenna arrays with applications in wireless communications, phased-array radar sensing, microwave/mm-wave imaging, and radio astronomy instrumentation. The MD spectral properties of propagating plane-waves that arise from electromagnetics are combined with...
Because of the significant increase in size and complexity of the networks, the distributed computation of eigenvalues and eigenvectors of graph matrices has become very challenging and yet it remains as important as before. In this paper we develop efficient distributed algorithms to detect, with higher resolution, closely situated eigenvalues and corresponding eigenvectors of symmetric graph matrices...
Recently we have shown, by providing an explicit counterexample, that the structural stability of a linear 2D discrete Fornasini-Marchesini model is not equivalent to its asymptotic stability when dealing with boundary conditions on the positive axes. The main contribution of the present paper shows that this fact remains valid when dealing with linear 2D discrete Roesser models. Using the notion...
In recent years average life expectancy in developed countries has increased, hence the amount of people which depend on a wheeled walking frame and in addition are visually handicapped has grown. The independent mobility of this people is often limited since they need guidance by other humans. Recent research focused on technical guidance systems implemented on a walking frame. The mobile vehicle...
The dynamics of linear diffusion processes can be modelled by multi-dimensional transfer functions in a spatiotemporal frequency domain. Finite spatial domains with simple and impedance type boundary conditions are possible. The resulting discrete time synthesis algorithm captures the essential behaviour with a restricted number of modes. Dynamic diffusion processes are of interest for molecular communication...
Activity recognition has a growing interest in many fields like biomedical engineering, game development or for sports training. Sensors are attached to a human body to track body movement, physiological signals or environmental variables and these informations are interpreted by algorithms. The finding of characteristics of sensor data for the classification problem plays an important role and is...
A low-complexity 2-D FIR trapezoidal filter is proposed for enhancing broadband plane waves. Motivated by the design technique of 1-D interpolated FIR filters, the proposed filter is realized by cascading a low-complexity spatiallyupsampled 2-D FIR filter having a trapezoidal passband and a low-complexity 2-D FIR masking filter having a parallelogram passband. Experimental results confirm that the...
In this paper we consider 2D single-input/singleoutput behaviors described by linear partial difference equations with (2,2)-periodically varying coefficients, and present a method to obtain 2D Roesser state-space representations (or realizations) for such behaviors. Since these cannot be obtained by separately realizing each shiftinvariant system resulting from “freezing” the varying coefficients,...
Given 2D discrete vector-geometric trajectories generated by a controllable, quarter-plane causal system, we identify an unfalsified Roesser model for it. We first compute state trajectories from the factorization of constant matrices directly constructed from the data; the A, B, C and D matrices of the Roesser model are then determined solving a system of linear equations involving the data and the...
An image-driven, model-free approach to design control systems for a large class of industrial process is proposed. A mathematical model of the process is replaced by sequences of subsequent images which play the role of the process (plant) states. The length of this sequences depends on the speed of the process dynamics and on the frame rate. Firstly, a learning sequence of the system states is collected...
This article presents four state-space models for high pressure gas pipelines, departing from a system of nonlinear partial differential equations. The models were derived taking advantage of an electrical analogy and are very accurate and simple, therefore suitable for network simulation and analysis. The models’ simulation is compared with the data obtained with Simone, a commercial simulator of...
Repetitive processes complete the same operation defined over a finite interval of time over and over again. Once an execution, termed a pass, is complete the processes resets to the starting location. Once complete, the next pass can begin, either immediately after the end of resetting or after a further period of time. Each pass output is known as the pass profile and on any pass this profile contributes...
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