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Information, Communication and Automation Technologies (ICAT), 2011 XXIII International Symposium on

Date 27-29 Oct. 2011

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  • [Front cover]

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  • [Title page]

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  • Table of contents

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  • Conference information

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  • Convergence analysis for a class of source separation methods

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (163 KB) |  | HTML iconHTML  

    Blind Source Separation (BSS) is a topic of interest in different fields of information processing with a large span of applications, e.g., in communications, pattern recognition, brain activity monitoring and audio processing. This article reviews some convergence analysis results for parallel BSS algorithms that are used for the simultaneous extraction of sources. The emphasis will be on two major BSS schemes, namely, Indepenent Component Analysis and Bounded Component Analysis. The article underlines the major convergence results regarding these two branches and their connections. View full abstract»

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  • Reduced order dynamics and stability of a parallel manipulator through bond-graph technique

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1703 KB) |  | HTML iconHTML  

    Dynamic characteristics of complex systems are very important for control system design. This paper represents the differences between full and reduced order dynamical models of a generalized Stewart Platform Mechanism. Full model includes all the dynamics, gravity effects, viscous friction at the joints and the linear motor dynamics. Reduced order dynamics includes all the dynamics of full system model except linear motor dynamics. Both full/reduced order dynamics are modeled using bond-graph technique and nonlinear state-space representations of models are obtained. Stability of both models is investigated by observing the variations of the system matrix eigenvalues which are utilized from the state-space equations. Four different trajectories are applied to the full order and to the reduced order Bond-Graph model for validation purposes. Satisfactory match between full/reduced order models is achieved. View full abstract»

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  • Development of microgripper system

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (671 KB) |  | HTML iconHTML  

    The paper presents the experimental development of micro/nano robotic cell for assembling the micro objects. Three techniques for gripping of micro objects with micro/nano robot are presented. The first one uses a two finger gripper and is suitable for objects which are greater than 100 μm. The next technique uses the micro tube for development of pneumatic gripper and can be used for objects greater than 70 μm. The third technique is called a one finger gripper, which can be used for objects smaller than 70 μm. The 5 DOF micro/nano robot mechanism with linear step piezoelectric motors and its control system with man-machine communication are also described. View full abstract»

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  • Path finding simulator for mobile robot navigation

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (383 KB) |  | HTML iconHTML  

    This work considers the whole process of making a path finding simulator for Pioneer 3DX mobile robot. This simulator needs to be provided implementation of various optimal path finding algorithms and make their comparisons. For this purpose a software solution (GUI in Matlab) has been designed and tested. The simulator allows selecting mazes, different starting and finishing nodes and algorithms. Five different algorithms were used to determine the shortest path between nodes for a mobile robot within various mazes: Breadth-first search, Depth-first search, Bellman-Ford algorithm, Dijkstra's algorithm and A* algorithm. The main objective of this paper was to obtain fully and precise information on routing and finding the shortest path between two nodes within a maze for the mobile robot. Validity and effectiveness of the used algorithms were verified through both simulations and experiments. View full abstract»

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  • Operating characteristics of a passive, bidirectional overrunning clutch for rotary joints of robots

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2827 KB) |  | HTML iconHTML  

    For the development of robots the mode of assembly and the effectiveness of their joints are of elementary significance. To enable powerful movements, strong torques are required which, when employing electromechanical actuators, are generated by high-capacity motors in combination with adequate speed transformations. Furthermore, such drive systems have to withstand even very high external loads which can be caused by uncontrolled motions, e.g., by stumbling of a humanoid robot. In particular the gears have therefore to be of robust construction. Likewise, the energy efficiency of the drive systems plays a decisive role for the perseverance of robots. The latter underlies a negative impact especially by frictional losses of highly transforming gears. In the present publication a novel design of a clutch is described. It has been developed with the goal to equally meet the requirements both of high energy efficiency and capacitance of robots. Apart from its configuration, this paper mainly deals with the technical performance of the new clutch, especially in combination with the actuator used. View full abstract»

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  • The path planning algorithms for a mobile robot based on the occupancy grid map of the environment — A comparative study

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1698 KB) |  | HTML iconHTML  

    This paper presents a comparative study of three algorithms that use occupancy grid map of environments to find a path for a mobile robot from the given start to the goal - the D*, Two Way D* (TWD*) and E*. All three algorithms have ability of dynamic replanning in case of changes in the environment. The D* algorithm produces a path consisted of line segments that have discrete transitions between cell edges - a multiple of 45°. This path is hard to follow by a mobile robot. The TWD* and E* algorithms produce more natural paths with continuous headings of the path line segments. The criteria for comparison were the path characteristics, the time of execution and the number of iterations of the algorithms' main while loop. The algorithms were verified both by simulation and experimentally on a Pioneer 3DX mobile robot equipped with a laser range finder. View full abstract»

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  • Safe motion planning for articulated robots using RRTs

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1326 KB) |  | HTML iconHTML  

    We present a sampling-based motion planning approach for articulated manipulators that generates safe paths. It uses the rapidly-exploring random trees paradigm to establish a collision-free path in configuration space. The expansion of the trees is influenced by a modified version of the kinetostatic danger field - a safety assessment function recently proposed in the literature. The idea is to grow the trees towards safer regions. Thus, the planner provides not only collision-free paths, but strives for safer ones. We propose two versions of the planner. The first is a modification of the Jacobian Transpose-directed RRT (JT-RRT) algorithm that grows a single tree from the start configuration and uses the transpose of the Jacobian to guide the sampling towards the goal defined in the workspace. The second is an extension of the standard bidirectional RRT-connect planner where the inputs to the algorithm are the start and the goal configuration that serve as seeds for the trees growth. View full abstract»

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  • SmartLeg: An intelligent active robotic prosthesis for lower-limb amputees

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4502 KB) |  | HTML iconHTML  

    In recent years, there has been a worldwide interest in improvement of mobility of people with lower limb amputation. In spite of significant development of new technologies during the last decade, commercial below-knee and above-knee prostheses are still energetically passive devices. However, many locomotive functions, like walking up stairs and slopes, need significant power in knee and ankle joints. The additional power for doing previously mentioned activities needs to be achieved by means of external energy sources, which should be integral prosthetic components. This paper presents preliminary investigations towards an active robotic prosthesis that could potentially enable people with an above- or below-knee amputation to perform different types of motions that require power in lower limb joints. Our initial prototype, SmartLeg, integrates advanced prosthetic and robotic technology with the state-of-the-art machine learning algorithms capable of adapting the working of the prosthesis to the optimal gait and power consumption patterns, and which therefore provide means to customize the device to a particular user. View full abstract»

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  • Optimal torque control of the Interior Permanent Magnet Synchronous Machine

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (407 KB) |  | HTML iconHTML  

    The basic function of any type of electric machine used in automotive powertrain is to propel the automobile in motor mode or to recharge the high-voltage battery in generator mode. The torque control of electric machine in motor and generator modes, using more efficient high-voltage battery, is a goal for automotive industry. The entire control structure must be designed so as to take into account also the limitations of the computer based implementation in an Electronic Control Unit. A good choice for Hybrid Electric Vehicles (HEVs), due to many advantages, is the Interior Permanent Magnet Synchronous Machine (IPMSM). In this paper, a model for a 35 KW IPMSM used by a future HEV is presented. Starting from the developed model a dynamic simulator was implemented in MATLAB/SIMULINK and then, an optimal field oriented control strategy is applied with aims at optimum torque control both in constant torque region and in constant power region, considering the variation of machine parameters. The model was validated against the data provided by Continental Automotive Romania from the system testbench. The simulated results obtained with the proposed control strategy are compared with the ones obtained with the classical PID approach and the results show improved performances. View full abstract»

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  • Decentralized set-valued state estimation based on non-deterministic chains

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1191 KB) |  | HTML iconHTML  

    A general decentralized computational framework for set-valued state estimation and prediction for systems that assume a hybrid state machine representation is introduced in this article. The decentralized scheme consists of a conjunction of a finite set of distributed state machines that are specified by a decomposition of the external signal space. While, in general, the latter is shown to be an outer approximation of the corresponding outcome of the original state machine, here, specific rules for the signal space decomposition are devised by utilizing structural properties of the underyling transition relation, leading to a recovery of the exact state set results. Finally, we illustrate the reduction of the overall computational complexity in a decentralized setting by appyling ℓ-complete approximation representation of the distributed state machines. View full abstract»

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  • Using behavior models for anomaly detection in hybrid systems

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (262 KB) |  | HTML iconHTML  

    The importance of safety and reliability in today's real-world complex hybrid systems, such as process plants, led to the development of various anomaly detection and diagnosis techniques. Model-based approaches established themselves among the most successful ones in the field. However, they depend on a model of a system, which usually needs to be derived manually. Manual modeling requires a lot of efforts and resources. This paper gives a procedure for anomaly detection in hybrid systems that uses automatically generated behavior models. The model is learned from logged system's measurements in a hybrid automaton framework. The presented anomaly detection algorithm utilizes the model to predict the system behavior, and to compare it with the observed behavior in an online manner. Alarms are raised whenever a discrepancy is found between these two. The effectiveness of this approach is demonstrated in detecting several types of anomalies in a real-world running production system. View full abstract»

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  • Nonlinear model predictive control of a benchmark nonlinear boiler

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (243 KB) |  | HTML iconHTML  

    This paper presents a case study of nonlinear model predictive control (NMPC) applied to a benchmark nonlinear boiler model. The motivation for NMPC is that if the controlled plant exhibits nonlinear behavior, a linear controller based on a linearized model may often be unable to achieve satisfactory performance. The case study in this paper, a power plant boiler, exhibits significant nonlinearities and includes time delays. The NMPC controller based on this nonlinear model is developed and presented, and simulation results illustrate its performance. Thereby it is demonstrated, that MPC based on full nonlinear optimization is viable for control of power plant subsystems. View full abstract»

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  • Nonlinear observer design for a class of Lipschitz time-delay systems with unknown inputs: LMI approach

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (202 KB) |  | HTML iconHTML  

    In this paper, we consider a method to design a full-order nonlinear observer for a class of nonlinear time-delay systems with unknown inputs. Based on Lyapunov-Krasovskii functional, we derive a sufficient condition for existence of the designed observer which requires solving a set of nonlinear matrix inequalities. Then, the achieved condition is formulated in terms of two linear matrix inequalities (LMIs). Finally, the proposed observer is illustrated with an example. View full abstract»

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  • New edge sorting criterion for maximum clique search algorithm in unit disk graphs

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (227 KB) |  | HTML iconHTML  

    Unit disk graphs (UDG) are a natural choice for wireless network modeling. However, complex UDG algorithms with a long processing time could be ineffective because of nodes mobility and the lack of processing power of the nodes. Therefore, they should be adapted for use in wireless networks. In this paper we present an accelerated algorithm for maximum clique in UDG using simple calculations. The input of the algorithm is an ordered set of graph edges. Our approach is to decrease the number of edges involved in algorithm, and then to reorder the edges for faster processing. The ordering criterion uses two-hop neighborhood information. The simulation results show a significant shortening of algorithm processing time. Two types of node distribution, x-y and p-φ were tested. The results depend on the distribution type. This indicates a possibility to create adaptive algorithms fitted to a specific type of node distribution in the network. View full abstract»

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  • New forensic method for measuring dynamic changes of EMF level limits using smart dust

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1038 KB) |  | HTML iconHTML  

    Devices and appliances such as transformers, mobile phones and GSM antennas, or electro motors, produce, electromagnetic fields (EMF) around them during their operation. According to an International Commission on Non-Ionizing Radiation Protection (ICNIRP) levels above 2000 milligauss (mG) or 200 microtesla (μT) for occupants in general premises are considered as dangerous for human health. While this is international standard, national standards have different acceptable value levels of EMF strengths around devices and antennas. Scientists from 1979 are still trying to prove connection between serious health risk and EMF. As a step to make more clear this area of research in this paper is presented new application model for monitoring dynamic changes of EMF strength levels. This became more important after European Council and World Health Organization (WHO) in the May of 2011 changed their policies related to EMF and health risk. In this paper the health risk of EMF is not proven, and that was not an intention. Our concerns are EMF strength levels around devices and appliances and more specifically GSM antennas, and how strength levels can be monitored and controlled dynamically because of new knowledge by which EMF is connected to health risk. This paper presents new application model for collecting data about EMF strengths levels around devices and antennas which radiate EMF in dynamic manner using smart dust technology. View full abstract»

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  • Generalized orthogonalization method for finite discrete signals and its application

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    The problem of finding a pair of biorthogonal functions for the case of finite and discrete signals is considered. Starting from two initial functions which are not necessarily biorthogonal, a general procedure to construct biorthogonal ones is given. Compared to previous orthogonalization methods, this method is more general, flexible and also more systematic. Numerical results are also given to see how different parameters can result in different orthogonalized functions. View full abstract»

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  • A control engineering perspective to radio resource management challenges in emerging cellular/“noncellular” radio systems

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (265 KB) |  | HTML iconHTML  

    The technological evolution of the wireless cellular systems has been very rapid in last two decades. In the coming decade of “converging wireless networks/systems/ecosystems”, there is an increasing demand on achieving very high data rates ubiquitously even with high mobile speeds as if we connected to a wired ADSL! Radio Resource Management (RRM) for the emerging wireless systems will be the key mechanism for achieving such high data rates. Indeed, RRM has already been a hot research area in both academia and industry for decades. And due to the complexity of the emerging wireless systems, an interdisciplinary approach and/or methodology is needed to tackle the new RRM challenges. In this paper, we provide a control engineering view onto some of the RRM challenges in emerging wireless networks, with a special emphasis on distributed power control. For example, we establish a link between power control design and dynamic neural networks, two different areas whose scope of interest, motivations and settings are completely different. Here, we emphasize the importance and the need of interdisciplinary approach. Some subjects to be addressed within the paper shall include future-generation cellular/“noncellular” systems, radio resource management challenges, energy efficiency and distributed power control algorithms, variable-structure-systems based power control, channel/frequency allocation, spectral-clustering based channel allocation, Hopfield neural networks. View full abstract»

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  • Real-time co-operative decision making & control systems

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (554 KB) |  | HTML iconHTML  

    Learning and adaptability (and thus the ability of being co-operative) are important features of decision & control systems. This paper investigates decision making and control concepts that enable human beings and artificial beings to interact and co-operate in real time in a dynamic and reliable way. It examines the aspects of being co-operative and substitutable in the context of: (i) co-operative driving by driverless vehicles; and (ii) computer game play scenarios for collaborative and social interactions. View full abstract»

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  • Full Wave Analysis in 3D laser scans for vegetation detection in urban environments

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2130 KB) |  | HTML iconHTML  

    This paper presents a novel technique for detecting vegetation of virtually all forms in terrestrial laser scanning data of urban environments. We make use of a modern laser range finder capability to measure multiple echoes per laser pulse via Full Wave Analysis. The algorithm is able to efficiently, i.e., less than acquisition time, identify vegetation to a high degree of accuracy (more than 99 percent). We present and evaluate three alternatives to classify candidate regions as either vegetation or non-vegetation. View full abstract»

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  • Efficient processing of large 3D point clouds

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (254 KB) |  | HTML iconHTML  

    Autonomous robots equipped with laser scanners acquire data at an increasingly high rate. Registration, data abstraction and visualization of this data requires the processing of a massive amount of 3D data. The increasing sampling rates make it easy to acquire Billions of spatial data points. This paper presents algorithms and data structures for handling this data. We propose an efficient octree to store and compress 3D data without loss of precision. We demonstrate its usage for fast 3D scan matching and shape detection algorithms. We evaluate our approach using typical data acquired by mobile scanning platforms. View full abstract»

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