Showing papers in "Bulletin of The Polish Academy of Sciences-technical Sciences in 2010"
TL;DR: In this article, the authors present some recent results in the area of application of fractional order system models for real-world phenomena such as ultracapacitor and beam heating.
Abstract: . This paper presents some recent results in the area of application of fractional order system models. After the introduction to the dynamic systems modelling with the fractional order calculus the paper concentrates on the possibilities of using this approach to the modelling of real-world phenomena. Two examples of such systems are considered. First one is the ultracapacitor where fractional order models turn out to be more precise in the wider range of frequencies than other models used so far. Another example is the beam heating problem where again the fractional order model allows to obtain better modelling accuracy. The theroetical models were tested experimentally and the results of these experiments are described in the paper.
185 citations
TL;DR: This article studies the differential-geometrical structure of a manifold induced by a divergence function, which consists of a Riemannian metric, and a pair of dually coupled affine connections, which are studied in information geometry.
Abstract: Measures of divergence between two points play a key role in many engineering problems. One such measure is a distance function, but there are many important measures which do not satisfy the properties of the distance. The Bregman divergence, KullbackLeibler divergence and f -divergence are such measures. In the present article, we study the differential-geometrical structure of a manifold induced by a divergence function. It consists of a Riemannian metric, and a pair of dually coupled affine connections, which are studied in information geometry. The class of Bregman divergences are characterized by a dually flat structure, which is originated from the Legendre duality. A dually flat space admits a generalized Pythagorean theorem. The class of f -divergences, defined on a manifold of probability distributions, is characterized by information monotonicity, and the Kullback-Leibler divergence belongs to the intersection of both classes. The f -divergence always gives the α-geometry, which consists of the Fisher information metric and a dual pair of ±α-connections. The α-divergence is a special class of f -divergences. This is unique, sitting at the intersection of the f -divergence and Bregman divergence classes in a manifold of positive measures. The geometry derived from the Tsallis q-entropy and related divergences are also addressed.
169 citations
127 citations
TL;DR: In this article, the authors review the recent advances in the techniques for formation of bubbles of gas and droplets of liquid in two-phase microfluidic systems and review the fundamental forces at play, and the mechanism of formation of bubble and droplet that is responsible for the observed monodispersity.
Abstract: The lecture will review the recent advances in the techniques for formation of bubbles of gas and droplets of liquid in two-phase microfluidic systems. Systems comprising ducts that have widths of the order of 100 μm produce suspensions of bubbles and droplets characterized by very narrow size distributions. These systems provide control over all the important parameters of the foams or emulsions, from the volumes of the individual bubbles and droplets, through the volume fraction that they occupy, the frequency of their formation, and the distribution of sizes, including monodisperse, multimodal and non-Gaussian distributions. The lecture will review the fundamental forces at play, and the mechanism of formation of bubbles and droplets that is responsible for the observed monodispersity.
97 citations
TL;DR: It is suggested, that thrombogenic potential of platelet-derived microparticles, which can be accurately measured in blood plasma, offers very useful estimate of hemocompatibility.
Abstract: Hemocompatibility test of medical materials aims to detect adverse interaction between artificial surface and blood, which can activate or destruct blood components. In arterial flow conditions, due to a high shear stress, platelet is the cell critical for the hemocompatibility compliance. A classical instrumentation for the dynamic test of hemocompatibility involves a flow chamber with a contact surface between blood stream and tested plate. In the current study we investigated a simplified model of the whole blood shear stress, based on a cone and plate rotational viscometer. Several indices of platelet activation were analyzed, including plateletand granulocyte-platelet aggregates, platelet activation markers and platelet-derived microparticles. This model allowed to estimate platelet destruction, however no adhesion could be measured directly. In following tests of several polymer and metallic layer coated materials, the test revealed comparable performance to more laborious hemocompatibility experiments. We suggest, that thrombogenic potential of platelet-derived microparticles, which can be accurately measured in blood plasma, offers very useful estimate of hemocompatibility. Moreover, this parameter has already been validated in clinics and could be used for monitoring of implanted cardiovascular materials.
47 citations
TL;DR: Direct and indirect evidences are presented that support the view that some proteins change their conformation upon adsorption, and it is shown that both physical and chemical methods are needed to study the extent and kinetics of protein conformational changes.
Abstract: Protein adsorption on solid surfaces is a widespread phenomenon of large biological and biotechnological significance. Conformational changes are likely to accompany protein adsorption, but are difficult to evidence directly. Nevertheless they have important consequences, since the partial unfolding of protein domains can expose hitherto hidden amino acids. This remodeling of the protein surface can trigger the activation of molecular complexes such as the blood coagulation cascade or the innate immune complement system. In the case of extracellular matrix, it can also change the way cells interact with the material surfaces and result in modified cell behavior. In this review, we present direct and indirect evidences that support the view that some proteins change their conformation upon adsorption. We also show that both physical and chemical methods are needed to study the extent and kinetics of protein conformational changes. In particular, AFM techniques and cryo-electron microscopy provide useful and complementary information. We then review the chemical and topological features of both proteins and material surfaces in relation with protein adsorption. Mutating key amino acids in proteins changes their stability and this is related to material-induced conformational changes, as shown for instance with insulin. In addition, combinatorial methods should provide valuable information about peptide or antibody adsorption on well-defined material surfaces. These techniques could be combined with molecular modeling methods to decipher the rules governing conformational changes associated with protein adsorption.
45 citations
TL;DR: In this article, the stability analysis of a closed-loop SISO linear system with a controller described by the equations mentioned is investigated, and a stability condition based on a transient denominator matrix condition number is proposed.
Abstract: Variable, fractional-order backward difference is a generalisation of commonly known difference or sum. Equations with these differences can be used to describe a variable-, fractional order digital control strategies. One should mention, that classical tools such as a state-space description and discrete transfer function cannot be used in the analysis and synthesis of such a type of systems. Equations describing a closed-loop system are proposed. They contain square matrices imitating the action of matrices in the system polynomial matrix description. This paper focuses on the stability analysis of a closed-loop SISO linear system with a controller described by the equations mentioned. A stability condition based on a transient denominator matrix condition number is proposed. Investigations are supported by two numerical examples.
43 citations
TL;DR: In this article, the robust stability of linear positive discrete-time systems of fractional order with structured perturbations of state matrices is studied. And the necessary and sufficient conditions for robust stability in the general case and in the case of linear uncertainty structure with unity rank uncertainty structure and with non-negative perturbation matrices are established.
Abstract: The paper is devoted to the problem of robust stability of linear positive discrete-time systems of fractional order with structured perturbations of state matrices. Simple necessary and sufficient conditions for robust stability in the general case and in the case of linear uncertainty structure with unity rank uncertainty structure and with non-negative perturbation matrices, are established. It is shown that robust stability of the positive discrete-time fractional system is equivalent to: 1) robust stability of the corresponding positive discrete-time system of natural order in the general case, 2) robust stability of the corresponding finite family of positive discrete-time systems of natural order in the case of linear unity rank uncertainty structure, 3) asymptotic stability of only one corresponding positive discrete-time system of natural order – in the case of linear uncertainty structure with non-negative perturbation matrices. Moreover, simple necessary and sufficient condition for robust stability of the positive interval discrete-time linear systems of fractional order is given. The considerations are illustrated by numerical examples.
42 citations
TL;DR: A brief overview of the routes and mechanisms which have been used to create self healing behavior in the principal classes of engineering materials: polymers, metals, ceramics, concrete, asphalt, fiber composites, is presented in this article.
Abstract: Modern man-made engineering materials demonstrate excellent mechanical properties, but the lack of the ability of self healing, i.e. the ability to remove or neutralise microcracks without (much) intentional human interaction, which is typical for most materials as encountered in nature. Such self-healing behaviour requires the presence of mobile species, atoms or molecules, in an otherwise solid material. Upon the occurrence of damage the mobile species directionally flow towards the damage location and once arrived there restores the contact between the two crack faces and the mechanical integrity. This directional flow may occur during regular use conditions (self healing behaviour) or conditions during which the mobility is temporarily increased (stimulated self healing). In this manuscript a brief overview of the routes and mechanisms which have been used to create self healing behaviour in the principal classes of engineering materials: polymers, metals, ceramics, concrete, asphalt, fibre composites, is presented.
40 citations
TL;DR: The Necessary-preferenceenhanced Evolutionary Multiobjective Optimizer (NEMO) as mentioned in this paper combines an evolutionary multiobjective optimization with robust ordinal regression within an interactive procedure.
Abstract: This paper presents the Necessary-preference-enhanced Evolutionary Multiobjective Optimizer (NEMO), which combines an evolutionary multiobjective optimization with robust ordinal regression within an interactive procedure. In the course of NEMO, the decision maker is asked to express preferences by simply comparing some pairs of solutions in the current population. The whole set of additive value functions compatible with this preference information is used within a properly modified version of the evolutionary multiobjective optimization technique NSGA-II in order to focus the search towards solutions satisfying the preferences of the decision maker. This allows to speed up convergence to the most preferred region of the Pareto-front.
38 citations
TL;DR: The paper presents one of the examples of utilization of this approach to structuring robot control systems, and concerns the multi-robot drawing copying system.
Abstract: The paper deals with structuring robot control systems. The control system is decomposed into distinct agents. An agent, in general, is responsible for control of its effector, perception of the environment for the purpose of its effector control, and inter-agent communication. The behaviour of the agent is governed by its set of transition functions. The control system consists of two tiers – the upper tier is defined by the flow of information between the agents and the lower tier is defined by formal specification of each agent’s behaviour (influence on the environment, gathering sensor readings, production and consumption of the information for/from the other agents). The paper presents one of the examples of utilization of this approach. The example concerns the multi-robot drawing copying system.
TL;DR: The role of phase transformation theory in the development of innovative steels is assessed in this article, focusing on examples where the relationship is transparent, and all of the major transformations, ranging from those which necessarily involve diffusion, to others where the change in crystal structure is achieved by a deformation.
Abstract: The role of phase transformation theory in contributing to the development of innovative steels is assessed, focusing on examples where the relationship is transparent. Virtually all of the major transformations, ranging from those which necessarily involve diffusion, to others where the change in crystal structure is achieved by a deformation, are considered.
TL;DR: In this article, the eigenfunction equation of fractional variational operator including left and right derivative of order α is solved using the fixed point theorem and its exact and approximate solutions are studied in detail.
Abstract: The eigenfunction equation of fractional variational operator including left and right derivative of order α is solved using the fixed point theorem. Its exact and approximate solutions are studied in detail. The corresponding boundary conditions are derived by means of the composition rules of fractional operators and the theorem on a unique particular solution of the considered fractional differential equation is proved.
TL;DR: In this article, the problem of failure of the elastic bearing supporting the generator in a harmonic drive is presented, and material investigations as well as simulations of the stress state in the bearing versus manufacturing deviations and fits between the bearing and the generator cam have been carried out.
Abstract: In the paper, the problem of failure of the elastic bearing supporting the generator in a harmonic drive is presented. To analyse the cause of the failure, material investigations as well as simulations of the stress state in the bearing versus manufacturing deviations and fits between the bearing and the generator cam have been carried out. Studies on the stress state in the flexpline have also been conducted in dependence of such technological deviations and generator bearing-flexspline fits for the classical, short, and ultra-short version of the harmonic drive with different heights of the bottom. The simulations have been realised on a mathematical model based on analytical relationships and a 3D model with the aid of FEM.
TL;DR: In this article, the influence of temperature and vapour energy on surface topography formation is analyzed for physical or chemical vapour-deposition (PVD, CVD) films.
Abstract: Functionalization of surfaces is an important task for nanotechnology to add specially designed physico-chemical properties to materials. Besides chemical modification of surfaces, physical adaptations gain increasing interest. Thus, understanding the influences of film deposition on surface topography formation is the basis for future developments. For physical or chemical vapour deposited (PVD, CVD) films, structure zone models were developed, clearly showing the influences of temperature and vapour energy and, thus, surface and bulk diffusion on film structures based on four different structure zones. Generally, similar zones are also found in PVD coatings on polymeric substrates; However, due to restrictions in coating temperatures due to the thermal resistance of most polymers, the coating temperature is restricted to mostly 50 ̊C, excluding thermal activation of at least surface diffusion of inorganic materials (metals and their nitrides, oxides, carbides, etc.) and resulting in columnar growth with dome-shaped column tops. Additionally, the high difference in mechanical properties between “stiff” inorganic coatings and “flexible” polymers implicates stress-induced growth phenomena, resulting in wrinkling, cracking and finally the formation of a superseding structure, depending on substrate and film materials and the vapour energy of the deposition method.
TL;DR: In this paper, the practical stability and the asymptotic stability of positive and cone fractional 1D and 2D linear systems are established and the necessary and sufficient conditions for the practical and sufficient stability of these systems were established.
Abstract: Notations of the practical stability and of the asymptotic stability of positive and cone fractional 1D and 2D linear systems are introduced Necessary and sufficient conditions for the practical stability and the asymptotic stability of positive and cone fractional 1D and 2D linear systems are established It is shown that the checking of the practical stability and asymptotic stability of positive 2D linear systems can be reduced to testing the stability of corresponding 1D positive linear systems Three LMI approaches are proposed for checking the stability of positive fractional linear systems LMI approach is applied to compute gain matrices of state-feedbacks such that closed-loop systems are positive and asymptotically stable The proposed methods are illustrated on numerical examples
TL;DR: A strong influence of the stoichiometry of TiN (atomic ratio of Ti/N) on the biocompatibility is found and a non-stoichiometric TiN could have a negative influence on the surrounding tissue.
Abstract: Since 1991, the Foundation for Cardiac Surgery Development in Zabrze has been implementing research on the artificial heart. In 1995, an artificial ventricle, POLVAD, was implanted to a patient, and in 1998, the prototype of a clinical controller, POLPDU-401, was created. A further development of the studies on an implantable artificial heart requires an integrated approach and an application of advanced methods of materials sciences in order to develop new materials suitable for the contact with blood, as well as to apply a multilateral biomedical diagnostics in hydrodynamic conditions. The estimation of the cell–material interaction plays an important role in the biomaterial design. An analysis of the influence of the carbon content in titanium nitride on the biological and biophysical properties of biomaterial coatings was studied. The cell-material reactions were considered in dynamic and static conditions. Three groups of materials were under examinations – titanium nitride (TiN), as well as titanium carbonitride with a low and high carbon content – of which the best properties were observed for TiN. We found a strong influence of the stoichiometry of TiN (atomic ratio of Ti/N) on the biocompatibility. A non-stoichiometric TiN could have a negative influence on the surrounding tissue.
TL;DR: In this paper, the authors analyze the dynamics of a self-guided anti-aircraft system during the launch of a single-missile system and present the results of the computer simulation of motion of the system.
Abstract: The analysis focuses on the dynamics of a hypothetical anti-aircraft system during the missile launch. The results of the computer simulation of motion of the launcher-missile system are represented graphically. The diagrams provide information about the range of kinematic excitations acting on the opto-electro-mechanical coordinator of the target in a self-guided missile.
TL;DR: A new classification scheme for integration scenarios is presented and the modeling and integration approach is explained together with a proof-of-concept use case and prototype, located in automation engineering.
Abstract: Model-driven software engineering is a well investigated and heavily used technique for software development. Within automation engineering we want to benefit from these ideas and concepts by adopting them to systems engineering. Parallel processes in systems engineering demand high synchronization effort between different disciplines, their engineers, and processes. Unfortunately, these processes are concurrently established, but do only support sequential engineering. With model-driven systems engineering we want to enable systems engineers to model their domain knowledge and tooling on a more abstract level. Thus, engineers may benefit in increasing efficiency and quality for the resulting products from existing integration approaches of engineering artifacts and tools. By means of an integration approach we are able to synchronize and check consistency of model data that evolved parallel in different tools. In this contribution, we present a new classification scheme for integration scenarios and explain our modeling and integration approach together with a proof-of-concept use case and prototype, located in automation engineering.
TL;DR: In this paper, the problems of asymptotic stability and robust stability of the new general 2D model of scalar linear dynamic continuous-discrete systems, standard and positive, are considered.
Abstract: The problems of asymptotic stability and robust stability of the new general 2D model of scalar linear dynamic continuous-discrete systems, standard and positive, are considered. Simple analytic conditions for asymptotic stability and for robust stability are given. These conditions are expressed in terms of coefficients of the model. The considerations are illustrated by numerical examples. The methods proposed can be generalized to scalar Fornasini-Marchesini and Roesser models of 2D continuous-discrete systems.
TL;DR: The proposed optimization method is based on utilizing tri-state buffers, thus enabling achievement of a one-logic-level output block, designed for PAL-based CPLDs implementations.
Abstract: The paper is concerned with the problem of state assignment and logic optimization of high speed finite state machines. The method is designed for PAL-based CPLDs implementations. Determining the number of logic levels of the transition function before the state encoding process, and keeping the constraints during the process is the main problem at hand. A number of coding bits, as well as codes for the states, are adjusted to achieve a machine with a determined number of logic levels. Elements of two-level minimization are taken into consideration in the state assignment. The proposed optimization method is based on utilizing tri-state buffers, thus enabling achievement of a one-logic-level output block.
TL;DR: The article deals with prototyping problems in constructing autonomous walking machines including design problems, evaluation of required motor power, Evaluation of expecting walking velocity as well as the control system design considerations etc., presenting themselves as key factors which must be taken into account while walking robots prototyping.
Abstract: An improvement of the computer technology caused the progress in building of the developed machines, indispensable in some works which are too dangerous or onerous for humans. The article deals with prototyping problems in constructing autonomous walking machines including design problems, evaluation of required motor power, evaluation of expecting walking velocity as well as the control system design considerations etc., presenting themselves as key factors which must be taken into account while walking robots prototyping.
TL;DR: In this paper, the actual level of fiber laser development is presented and the analysis of technological and constructional conditions that limit energy parameters of those sources is presented, and a construction and a technological work, conducted in Poland, which led to improving energy and exploit parameters.
Abstract: In this paper the actual level of fiber lasers’ development is presented. There is also presented the analysis of technological and constructional conditions that limit energy parameters of those sources. Authors also show a construction and a technological work, conducted in Poland, which led to improving energy and exploit parameters
TL;DR: The environment representation, the description language for tasks and service interfaces definition, as well as the protocols constitute together the proposed information technology for automatic task accomplishment in an open heterogeneous multirobot system.
Abstract: An approach to the problem of interoperability in open and heterogeneous multirobot system is presented. It is based on the paradigm of Service Oriented Architecture (SOA) and a generic representation of the environment. A robot, and generally a cognitive and intelligent device, is seen as a collection of its capabilities exposed as services. Several experimental protocols (for publishing, discovering, arranging, and executing the composite services) are proposed in order to assure the interoperability in the system. The environment representation, the description language for tasks and service interfaces definition, as well as the protocols constitute together the proposed information technology for automatic task accomplishment in an open heterogeneous multirobot system.
TL;DR: The main problem in the average power theory comes from the Schwartz inequality, which causes numerous optimization problems, among which the norm of the current minimization is the most important one.
Abstract: In optimization power theory we can distinguish the three approaches: • the theory of instant power values • the theory of average power values (integral power) • the theory of instant–average power value. The theory of instant power uses the instant power and signals values i.e. p(t) = u(t)i(t) whereas the theory of average power uses the energy or average power terms i.e. P = (u(t), i(t)) (the dot the product of signals). The main problem in the average power theory comes from the Schwartz inequality: |(u, u)| ≤‖ u ‖ ‖ i ‖, where ‖ u ‖= p (u, u), ‖ i ‖= p (i, i). This inequality causes numerous optimization problems, among which the norm of the current minimization is the most important one: ‖ i ‖→ min, (u, i)− P = 0. Whereas the theory of instant-average power values joins both aforementioned methods and uses so-called ‘instant active power’:
TL;DR: In this article, a localization system for a mobile robot using the vision system and LED markers is presented, which considers the problem of velocity and acceleration estimation in the case of planar motions.
Abstract: The paper presents a localization system for a mobile robot using the vision system and LED markers and considers the problem of velocity and acceleration estimation in the case of planar motions. Theoretical considerations include the principle of measurement and the details of Kalman estimator with illustrations based on experimental setup. The presented measurement system can be used for a realization of advanced control algorithms for skid-steering mobile robots where significant slippage phenomenon appears.
TL;DR: The paper presents the robot’s kinematic wheel suspension system, general operation strategy and control system, the application responsible for robot control and data visualization is described, and selected tests of the algorithms are presented.
Abstract: The wheel-legged robot is a vehicle with many degrees of freedom. Thanks to its peculiar design, depending on the need, the vehicle will use one of its ways of moving: travelling on wheels or walking (in special situations), which enhances its locomotive properties. The paper presents the robot’s kinematic wheel suspension system, general operation strategy and control system. The application responsible for robot control and data visualization is described. Finally, selected tests of the algorithms, carried out on the robot prototype, are presented.
TL;DR: In this article, the effect of the kinematic action resulting from the basic motion of the vehicle on the dynamics of the launcher and the gyroscope acting as the drive of the opto-electro-mechanical target coordinator in a self-guided missile was analyzed using a short-range anti-aircraft system.
Abstract: The work considers the effect of the kinematic action resulting from the basic motion of the vehicle on the dynamics of the launcher and the gyroscope acting as the drive of the opto-electro-mechanical target coordinator in a self-guided missile. The problem was analyzed using a hypothetical short-range anti-aircraft system. The simulation results were represented graphically.
TL;DR: The numerical part of this paper contains an investigation of some special semi-Markov models, where the results are presented of the calculation of the quality of service (QoS) parameters and the main measures of effectiveness.
Abstract: Based on the semi-Markov process theory, this paper describes an analytical study of a loss multiple-server two-station network model with blocking. Tasks arrive to the tandem in a Poisson fashion at a rate λ, and the service times at the first and second stations are non-exponentially distributed with means s and s , respectively. Between these two stations there is a buffer with finite capacity. In this type of network, if the buffer is full, the accumulation of new tasks (jobs) by the second station is temporarily suspended (blocking factor) and tasks must wait on the first station until the transmission process is resumed. Any new task that finds all service lines at the first station occupied is turned away and is lost (loss factor). Initially, in this document, a Markov model of the loss tandem with blocking is investigated. Here, a two-dimensional state graph is constructed and a set of steady-state equations is created. These equations allow the calculation of state probabilities for each graph state. A special algorithm for transforming the Markov model into a semi-Markov process is presented. This approach allows calculating steady-state probabilities in the semi-Markov model. In the next part of the paper, the algorithms for calculation of the main measures of effectiveness in the semi-Markov model are presented. Finally, the numerical part of this paper contains an investigation of some special semi-Markov models, where the results are presented of the calculation of the quality of service (QoS) parameters and the main measures of effectiveness.
TL;DR: The structure of the motivation model and formal assumptions regarding the task of solving the model were described and the proposed approach to solving the task bases on the games theory was proposed.
Abstract: The article contains the concept of developing a motivation model aimed at supporting activity of both students and teachers in the process of implementing and using an open and distance learning system. Proposed motivation model is focused on the task of filling the knowledge repository with high quality didactic material. Open and distance learning system assures a computer space for the teaching/learning process in open environment. The structure of the motivation model and formal assumptions regarding the task of solving the model were described. The proposed approach to solving the task bases on the games theory.