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Introduction. Farmers make extensive use of two-wheel tractors equipped with traction and drive interchangeable units. Two-wheel tractors are required to move evenly with minimal slip of the drive wheels on the soil. The tractive force on the drive wheels of the tillage unit is the decisive power factor in this case. An objective traction force value can be measured only by carrying out experimental studies. Materials and Methods. To determine the traction force on the drive wheels of the twowheel tractor, the design of the experimental stand was proposed and substantiated (RF patent for useful model No. 188610 “Movable module of the test stand”), and a methodology for planning and conducting a multifactor experiment to determine the traction force was developed. Results. As a result of the laboratory tests the calculation dependencies of the tractive force on the drive wheels of the Neva MB23-MultiAGRO Pro two-wheel tractor were obtained. Soil conditions, design and technological parameters, operating modes of the two-wheel tractor, and rolling resistance forces were taken into account. Discussion and Conclusion. The use of the developed regression models of the traction force under the condition of ensuring uniform movement with the minimum permissible slipping of the driving wheels of the two-wheel tractor on the soil will allow obtaining the permissible values of the two-tractor motion speed and form the zones of its most effective functioning.

This paper presents a survey of controller design techniques aimed at autonomous navigation and control of Unmanned Aerial Vehicles (UAVs), focusing on the challenge of aerodynamic uncertainty. Although many roadblocks exist, the most significant and challenging task for UAV navigation and control is the one of aerodynamic/model uncertainty. Current autopilots and controller designs for autonomous airplanes are mainly concerned with the feature of constant, unknown aerodynamic parameters, i.e., control and stability derivatives of the platform. This research focuses on a thorough investigation of the related theory and its applicability, centering on specific techniques that are able to control UAVs with rapidly changing, time-varying aerodynamic characteristics during flight. The scientific merit of this work is the comprehensive overview provided and the technical study that is performed, highlighting the advantages and disadvantages for each technique with respect to its efficiency and performance.

Statistical Dialogue Systems (SDS) have proved their humongous potential over the past few years. However, the lack of efficient and robust representations of the belief state (BS) space refrains them from revealing their full potential. There is a great need for automatic BS representations, which will replace the old hand-crafted, variable-length ones. To tackle those problems, we introduce a novel use of Autoencoders (AEs). Our goal is to obtain a low-dimensional, fixed-length, and compact, yet robust representation of the BS space. We investigate the use of dense AE, Denoising AE (DAE) and Variational Denoising AE (VDAE), which we combine with GP-SARSA to learn dialogue policies in the PyDial toolkit. In this framework, the BS is normally represented in a relatively compact, but still redundant summary space which is obtained through a heuristic mapping of the original master space. We show that all the proposed AE-based representations consistently outperform the summary BS representation. Especially, as the Semantic Error Rate (SER) increases, the DAE/VDAE-based representations obtain state-of-the-art and sample efficient performance.

The approach to apply AC voltage regulators for asynchronous motors connection to the power supply is discussed in the article. An assessment of AC voltage regulators power is made. Sinusoidal thyristor AC voltage regulator is presented. It provides high resolution of voltage regulation on the stator windings of the asynchronous motor during its start-up and in the steady state of its operation. The analysis of electromagnetic processes during the operation of the thyristor AC voltage regulator in dynamic modes is done. The simulation of AC motor start up process from power supply with the help of thyristor AC voltage regulator in Matlab/Simulink is presented. The advantages of AC motors connection to the power supply with the help of AC voltage regulators are considered.

Purpose Metamaterials have been utilised in several exciting configurations such as tuneable reflectors, reconfigurable absorbers, and programmable modulators, triggering intense research efforts. Among them, the ability to steer the radiation pattern of a single antenna component by employing a metamaterial-based superstrate is considered crucial for the development of advanced beam forming applications. The purpose of this paper is to introduce an adjustable omega-inspired metamaterial module to facilitate the design of beam steering implementations, involving beam forming capabilities, as well. Design/methodology/approach A variable capacitive diode is properly positioned at the novel omega element, hence advancing the controllability of its electromagnetic performance and circumventing the requirement of extra bias networks. When an array of these particles is placed in front of an antenna, several negative refractive index profiles can be realised, allowing the manipulation of the beam direction. Furthermore, a pyramidal horn antenna, loaded with this complex medium superstrate, is thoroughly investigated in terms of programmable beam steering and beam forming attributes. Several numerical data derived via the finite element method unveil the merits of the featured configuration. Findings The proposed structure allows programmability of the electromagnetic behaviour, but also circumvents the necessity of complicated bias networks, while minimising interference. The numerical assessment of a standard gain pyramidal horn antenna, associated to the featured metamaterial superstrate, sufficiently proves the controllable beam steering and beam forming attributes. Several parametric studies clarify the principal characteristics of the proposed setup, facilitating the design of high-end systems. Originality/value Development of tuneable metamaterial, which utilises variable capacitive diodes to enable controllability. Incorporation of reconfigurable metamaterials into antenna technology. Design of a pyramidal horn antenna, loaded with a complex medium superstrate exhibiting programmable beam steering and beam forming attributes. The proposed device circumvents the necessity of complicated bias networks, while minimising interference.

Summarization: Humanitarian Crisis scenarios typically require immediate rescue intervention. In many cases, the conditions at a scene may be prohibitive for human rescuers to provide instant aid, because of hazardous, unexpected, and human threatening situations. These scenarios are ideal for autonomous mobile robot systems to assist in searching and even rescuing individuals. In this study, we present a synchronous ground-aerial robot collaboration approach, under which an Unmanned Aerial Vehicle (UAV) and a humanoid robot solve a Search and Rescue scenario locally, without the aid of a commonly used Global Navigation Satellite System (GNSS). Specifically, the UAV uses a combination of Simultaneous Localization and Mapping and OctoMap approaches to extract a 2.5D occupancy grid map of the unknown area in relation to the humanoid robot. The humanoid robot receives a goal position in the created map and executes a path planning algorithm in order to estimate the FootStep navigation trajectory for reaching the goal. As the humanoid robot navigates, it localizes itself in the map while using an adaptive Monte-Carlo Localization algorithm by combining local odometry data with sensor observations from the UAV. Finally, the humanoid robot performs visual human body detection while using camera data through a Darknet pre-trained neural network. The proposed robot collaboration scheme has been tested under a proof of concept setting in an exterior GNSS-denied environment. Presented on: Drones

Background: Hand digit reconstruction with transposition of hand segments in cases of hand injury is not used frequently by surgeons, at least in part because of potential ischemic complications after cicatricial changes in tissues. The aim of this study was to investigate the opportunities for expanding the set of indications for hand digit reconstruction using scarred and deformed donor segments. Methods: We developed a technique of ischemic preconditioning and preforming the segment before transfer to improve macro-circulation and micro-circulation in scarred donor segments with a view to preventing ischemic complications in reconstructed digits. It was validated using clinical, radiological, morphological, and biophysical (IR imaging, laser Doppler flowmetry, rheovasography) methods. Results: A total of 184 patients were included. Primary digit reconstruction was performed in 19 patients while secondary reconstruction—in 165 patients. Single-stage transfer was performed in 122 hands, delayed transfer—in 67 hands. The total number of reconstructed thumbs and fingers was 203. Digit viability, stability, mobility and range of motion were very good with the use of new technique. Conclusions: When transferring hand segments with severe and highly severe deformations, tissue scarring and vascular damage, it is beneficial to pre-train the donor segment against hypoxia by both exsanguination and surgical methods.

This paper provides thyristors voltage regulator (TVR) which reliably operates at various characters of the load and is able to inject different levels of voltage in the transmission line. A method to eliminate overvoltage on thyristors during TVR operation is proposed. It also provides reliable operation of TVR during short circuit in power lines. The analysis of the TVR operation during a short circuit condition is performed. The simulation models to carry out studies of the TVR operation are proposed. The results of TVR operation on physical and simulation models are presented and analyzed.

The article describes the approach to carrying experimental studies of controlled phase shifters (CPS) operation on physical model of the transmission line. The objectives of the research are mathematical CPS and power line models verifications used for transmission line operation modes calculations. Description of the physical model of the transmission line and CPS prototype are presented. The basic ratios and methodology for calculation of mathematical model's parameters from experimental data, as well as the scheme for calculation of transmission line operation modes are presented. The experimental data confirming the validity of the CPS and the transmission line models are demonstrated.

The resonance type drivers have a greatest power efficiency. The analysis of resonance drivers with the LC-resonator and the fixed loading, working in a condition of autogeneration is carried out. Functional models of basic units of a self-regulation system are offered. On the basis of these models behavioral simulation of the 4-phase adiabatic driver is carried out. Outcomes of simulation have confirmed a possibility of deriving of high stabilization of output pulses amplitude at formulated requirements realization. It is shown, that at use of a hinged among choke on each clock trunk the efficiency of the driver can attain 90 % on 600 MHz frequency and 80 % on 1 GHz frequency at output pulses amplitude ∼ 3V. For the 4-phase drivers which are not using interconnection components, the efficiency of the driver can attain 50 % on 700 MHz frequency and is boosted up to 75 % at decrease of frequency. At increase of output pulses phases number the efficiency will increase.

This paper presents the electromagnetic traction characteristics of the vibration isolator rigidity compensator. When defining power, positioning characteristics against each axis should be taken into account. The equation was derived to describe the characteristics of each axis based on rigidity.

This paper deals with the research aimed at the efficiency upgrading techniques of start-up process of the diesel engines of shunt locomotives. The application features are indicated and methods of reliable start of the diesel engines with using of the supercapacitors are developed. The issues of reliability and lifetime of the supercapacitors stacks in start-up systems improvement are considered. The mathematical and simulation modelsare developed, changing of current - and speed-time curve charts are also presented.

This study examines the role of the Internet in the financial reporting practices of publicly traded Greek and Cypriot construction companies. Its key contribution is the development of a relevant index that is assessed against key business characteristics: profitability, leverage, audit firm size, firm size, ownership dispersion, time length of operations, and market to book value. The association between the proposed index and firm characteristics was examined with the use of multiple regression analysis. Our findings indicate, among others, that Internet-related financial disclosure is significantly associated with profitability, leverage, firm age and ownership dispersion., peer-reviewed

In this paper device for vibroisolation with Neodimium-Iron-Boron (NdFeB) supermagnets is presented. The use of the supermagnets allows developing device for vibroisolation with less size in comparison with present vibroisolators.

In this article the development of the perspective vibration protection device is described. The theory suggests the development of 3D-vibration isolator devices, which have power characteristics with zero stiffness area. A spatial vibroisolator is presented as an elastic element and stiffness compensator in-parallel of this element to obtain this specific area on power characteristic. This methodology allows us to make three-dimensional (3D) vibration isolator with electromagnetic stiffness compensator. This isolator allows to delete the vibration fluctuations in all three axes of space simultaneously. A spatial vibroisolated device consists of an elastic element and parallel 3D-electromagnetic stiffness compensator. An electromagnetic stiffness compensator is a two counter-mounted electromagnetic disks. Each disk is made as six electromagnetic or magnetic disconnected coils, and they are located two by two along three axes of space. The construction of one-dimensional vibration isolator with an electromagnetic stiffness compensator is presented in this article. Three-dimensional vibration isolator can be used in any area of mechanic, engineering, vibration dumping technique, which has a negative effect on human health and devices performance.

The design of complex dynamic motions for humanoid robots is achievable only through the use of robot kinematics. In this paper, we study the problems of forward and inverse kinematics for the Aldebaran NAO humanoid robot and present a complete, exact, analytical solution to both problems, including a software library implementation for real-time on-board execution. The forward kinematics allow NAO developers to map any configuration of the robot from its own joint space to the three-dimensional physical space, whereas the inverse kinematics provide closed-form solutions to finding joint configurations that drive the end effectors of the robot to desired target positions in the three-dimensional physical space. The proposed solution was made feasible through a decomposition into five independent problems (head, two arms, two legs), the use of the Denavit-Hartenberg method, the analytical solution of a non-linear system of equations, and the exploitation of body and joint symmetries. The main advantage of the proposed inverse kinematics solution compared to existing approaches is its accuracy, its efficiency, and the elimination of singularities. In addition, we suggest a generic guideline for solving the inverse kinematics problem for other humanoid robots. The implemented, freely-available, NAO kinematics library, which additionally offers center-of-mass calculations and Jacobian inverse kinematics, is demonstrated in three motion design tasks: basic center-of-mass balancing, pointing to a moving ball, and human-guided balancing on two legs.

The original definition of CRM describes it as a strategic process combining management practices, knowledge, resources and suitable customer information software of a firm to better serve the needs of its customers and to increase their loyalty. This view greatly depends on information technology support and software development.Is the acquirement of such software from the enterprise interconnected with the corporate strategy designed and the corporate culture developed?This paper examines on the correlation between the existence of customer information software in internationalized companies with concrete corporate strategies developed and implemented by the companies.Empirical results showed that when a corporation uses CRM information software, then multiple marketing strategies to approach customers and markets, complex market strategies and corporate strategies of high internationalization involvement are developed, facts that reflect the creation of a strategically structured, outward-oriented and customer focused corporate culture.

Purpose: Pelvic floor reconstructive surgery has grown significantly in recent years. A wide variety of available types of meshes exist but the safety and success has not been adequately proven. We sought to evaluate the effects on dynamic biomechanical properties of tissue after long-term implantation of synthetic and biological grafts. Methods: A total of 96 New Zealand white female rabbits (approximately 3 kg) were used, 72 of which were surgically implanted with acellular, collagen mesh (n = 36) or nonabsorbable monofilament polypropylene mesh (n = 36). There was a no mesh-rupture of fascia group (n = 12) and a second, no-mesh, no-fascia rupture control group (n = 12). In the 59 rabbits, of 72 (13 died) tissue was harvested 3 months (n = 24), 6 months (n = 23) and 9 months (n = 12) later, while in the fascia rupture group, tissue was harvested 6 months later. Tissue samples (2 × 2 cm) underwent dynamic mechanical analysis (DMA) testing during which the dynamic rigidity and tissue damping capacities were measured. The statistical analysis was performed with General Linear Model with Tukeys post hoc testing (sPss v.17.0). Results: With respect to mesh type, the rabbit tissue in which polypropylene mesh was used showed the greatest dynamic rigidity. Those with biological mesh delivered the lowest rigidity results, while the two other groups had almost similar behavior. The meshes exhibited their highest relative dynamic tissue stiffening effect at 9 months. Conclusions: Biological mesh causes lower tissue rigidity, resulting in inferior mechanical response and thus seems to be inferior to polypropylene.

This paper presents controlled phase shifters (CPS) unified model (UM) for power grid modes calculation. Internal different topologies of CPS which affect the parameters of the UM are considered. Parameters of UM for various CPS topologies are calculated and analyzed. The influences of different topologies and control on transfer functions of CPS are investigated. The implementation of UM for calculation of operating modes of a three-phase power grid with CPS based on thyristor controlled phase angle regulator (TCPAR) is presented. CPS impacts on operation modes of power grid are analyzed.

The paper deals with the development problems of economic and managerial competencies of bachelors after graduating from engineering higher schools to meet employers’ requirements, through implementing the Federal State Education Standards (FSES) of the third generation. The case study is conducted on the basis of training programs for the bachelor’s degree in Mechanical Engineering at Yurga Institute of Technology (Affiliate) of National Research Tomsk Polytechnic University. The list of economic and managerial competencies for bachelors in mechanical engineering is specified according to the third generation FSES, enlarged with new competences based on surveys and analyses after questioning employers. The criteria and indicators are described to identify maturity levels in terms of economic and managerial competencies for bachelors. A structural and functional model for training mechanical engineering bachelors has been tested in the implementation of the bachelor’s degree courses in "Mechanical engineering" at Yurga Institute of Technology (Affiliate) of National Research Tomsk Polytechnic University, in the period from 2011 to 2015.

Accuracy in design of steel and composite bridges against fatigue is strongly connected with the distinct features of regional traffic. However, the approach followed by Eurocode 1 (EN1991-...

Summarization: The increased power and resolution capabilities of 3T Magnetic Resonance (MR) scanners have extended the reach of Magnetic Resonance Spectroscopy as a non-invasive diagnostic tool. Practical sensor calibration issues, magnetic field homogeneity effects and measurement noise introduce distortion into the obtained spectra. Therefore, a combination of robust preprocessing models and nonlinear pattern analysis algorithms is needed in order to evaluate and map the underlying relations of the measured metabolites. The aim of this work is threefold. Firstly we propose the use of a paired support vector machine kernel utilizing metabolic data from both affected and normal voxels in the patient's brain for lesion classification problem. Secondly we quantify the performance of an optimal reduced feature set based on targeted CSI-144 scans in order to further reduce the data volume required for a reliable computed aided diagnosis. Thirdly we expand our previous formulation to full multiclass classification. The long term aim remains to provide the human expert with an easily interpretable system to assist clinicians with the time, volume and accuracy demanding diagnostic process. Παρουσιάστηκε στο: Biomedical Signal Processing and Control

A novel, phase-conjugator array for active, retro-directive operation has been made by use of three dual-gate, self-oscillating mixers (SOM's), mutually locked by use of 6 dB hybrid couplers. The coupling network incorporates the load of the oscillators. Reduced LO penetration has been achieved at the RF and IF and ports by trapping the LO signal within the dc bias lines of each SOM. Injection of two external signals at the LO frequency, each at a marginal SOM, with phase difference ΔΦ between them, allows for retransmission at angles other than the angle of arrival of the incident signal. Measured results are presented for a retro-directive array designed for nominal operation at 900 MHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1303–1309, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22447

The Standard Platform League is unique among RoboCup soccer leagues for its focus on software. Since all teams compete using the same hardware (a standard robotic platform), success is predicated on software quality, and the shared hardware makes quality judgments simpler and more objective. Growing out a league based on the Sony AIBO quadruped robots, the league has constantly evolved while moving ever closer to playing by human rules, and currently features the Aldebaran NAO humanoid robots. The hallmark of the league has been a focus on individual agents’ skills, such as perception, localization, and motion, at the expense of more team-oriented skills, such as positioning and passing. The league has begun to address this deficiency with the creation of the Drop-in Challenge, where robots from multiple teams will work together. This new focus should force teams to work on multi-agent coordination in more abstract and general terms and promises to create fruitful new lines of research.

Computer users with motor impairments find it difficult and, in many cases, impossible to access PC functionality through the physical keyboard-and-mouse interface. Studies show that even able-bodied users experience similar difficulties when interacting with mobile devices; this is due to the reduced size/usability of the input interfaces. Advances in speech recognition have made it possible to design speech interfaces for alphanumeric data entry and indirect manipulation (cursor control). Although several related commercial applications exist, such systems do not provide a complete solution for arbitrary keyboard and mouse access, such as the access needed for, say, typing, compiling, and executing a C++ program. We carried out a usability study to support the development of a speech user interface for arbitrary keyboard access and mouse control. The study showed that speech interaction with an ideal listening keyboard is better for users with motor impairments than handstick, in terms of task completion time (37% better), typing rate (74% better), and error rates (63% better). We believe that these results apply to both permanent and task-induced motor impairments. In particular, a follow-up experiment showed that handstick approximates conventional modes of alphanumeric input available on mobile devices (e.g., PDAs, cellular phones, and personal organizers). These modes of input include miniaturized keyboards, stylus “soft” keyboards, cellular phone numberpads, and handwriting recognition software. This result suggests that a listening keyboard would be an effective mode for alphanumeric input on future mobile devices. This study contributed to the development of SUITEKeys—a speech user interface for arbitrary keyboard and mouse access available for MS platforms as freeware.

The development of high-level behavior for autonomous robots is a time-consuming task even for experts. The Kouretes Statechart Editor (KSE) is a Computer-Aided Software Engineering (CASE) tool, which allows to easily specify a desired robot behavior as a statechart model utilizing a variety of base robot functionalities (vision, localization, locomotion, motion skills, communication) for the Monas robotic software architecture framework. This paper presents an extension to KSE, which allows defining generic agent behaviors using automatic framework-independent code generation, as long as the underlying framework is written in C++. This way a user can program physical (robots) or software agents that can be executed on any platform using any compatible software framework. This paper demonstrates the transparent use of the extended KSE in the SimSpark 3D soccer simulation and the Wumpus world.

A radial inhomogeneity of the gain in a cw CO2 laser with fast axial flow was studied experimentally and theoretically. It was found that this inhomogeneity resulted from a radial inhomogeneity of the temperature and contraction of a longitudinal self-sustained discharge towards the axis in a gas-discharge tube. This saturated the rise of the small-signal gain when the total discharge current was increased. It also reduced the rate of rise of the output radiation power with increase in the input energy when the fundamental Gaussian mode was generated.

Summarization: Several recent learning approaches based on approximate policy iteration suggest the use of classifiers for representing policies compactly. The space of possible policies, even under such structured representations, is huge and must be searched carefully to avoid computationally expensive policy simulations (rollouts). In our recent work, we proposed a method for directed exploration of policy space using support vector classifiers, whereby rollouts are directed to states around the boundaries between different action choices indicated by the separating hyper planes in the represented policies. While effective, this method suffers from the growing number of support vectors in the underlying classifiers as the number of training examples increases. In this paper, we propose an alternative method for directed policy search based on relevance vector machines. Relevance vector machines are used both for classification (to represent a policy) and regression (to approximate the corresponding relative action advantage function). Exploiting the internal structure of the regress or, we guide the probing of the state space only to critical areas corresponding to changes of action dominance in the underlying policy. This directed focus on critical parts of the state space iteratively leads to refinement and improvement of the underlying policy and delivers excellent control policies in only a few iterations, while the small number of relevance vectors yields significant computational time savings. We demonstrate the proposed approach and compare it with our previous method on standard reinforcement learning domains. Παρουσιάστηκε στο: 2012 IEEE International Conference on Tools with Artificial Intelligence

It is shown that using data the method of Current Trips in conjunction with Kalman filtration decrease confidence interval of the experimental measurement data inductance of micro chip line.

The RoboCup competition is the international robotic soccer world cup organized annually since 1997 The initial conception by Hiroaki Kitano in 1993 led to the formation of the RoboCup Federation with a bold vision: By the year 2050, to develop a team of fully autonomous humanoid robots that can win against the human world soccer champions! RoboCup poses a real-world challenge for Artificial Intelligence, which requires addressing simultaneously the core problems of perception, cognition, action, and coordination under real-time constraints In this talk, I will outline the vision, the challenges, and the contribution of the RoboCup competition in its short history I will also offer an overview of the research efforts of team Kouretes, the RoboCup team of the Technical University of Crete, on topics ranging from complex motion design, efficient visual recognition, and self-localization to robotic software engineering, distributed communication, skill learning, and coordinated game play My motivation is to inspire researchers and students to form teams with the goal of participating in the various leagues of this exciting and challenging benchmark competition and ultimately contributing to the advancement of the state-of-the-art in Artificial Intelligence and Robotics.

Coordinated Action in a Heterogeneous Rescue Team.- Concept Evaluation of a Reflex Inspired Ball Handling Device for Autonomous Soccer Robots.- Development of a Realistic Simulator for Robotic Intelligent Wheelchairs in a Hospital Environment.- Creating Photo Maps with an Aerial Vehicle in USARsim.- Real-Time Hand Gesture Recognition for Human Robot Interaction.- Combining Key Frame Based Motion Design with Controlled Movement Execution.- Applying Dynamic Walking Control for Biped Robots.- Modeling Human Decision Making Using Extended Behavior Networks.- Motion Synthesis through Randomized Exploration on Submanifolds of Configuration Space.- Robust and Computationally Efficient Navigation in Domestic Environments.- Robust Collision Avoidance in Unknown Domestic Environments.- Real-Time Ball Tracking in a Semi-automated Foosball Table.- Three Humanoid Soccer Platforms: Comparison and Synthesis.- Learning Complementary Multiagent Behaviors: A Case Study.- Rollover as a Gait in Legged Autonomous Robots: A Systems Analysis.- Pareto-Optimal Collaborative Defensive Player Positioning in Simulated Soccer.- A Novel Camera Parameters Auto-adjusting Method Based on Image Entropy.- Object Recognition with Statistically Independent Features: A Model Inspired by the Primate Visual Cortex.- Using Genetic Algorithms for Real-Time Object Detection.- An Approximate Computation of the Dominant Region Diagram for the Real-Time Analysis of Group Behaviors.- A Lua-based Behavior Engine for Controlling the Humanoid Robot Nao.- Stable Mapping Using a Hyper Particle Filter.- A Characterization of 3D Sensors for Response Robots.- Multiple Model Kalman Filters: A Localization Technique for RoboCup Soccer.- Integrated Genetic Algorithmic and Fuzzy Logic Approach for Decision Making of Police Force Agents in Rescue Simulation Environment.- IntellWheels MMI: A Flexible Interface for an Intelligent Wheelchair.- Analyzing the Human-Robot Interaction Abilities of a General-Purpose Social Robot in Different Naturalistic Environments.- Communicating among Robots in the RoboCup Middle-Size League.- Multi-robot Cooperative Object Localization.- Evolution of Biped Walking Using Truncated Fourier Series and Particle Swarm Optimization.- Efficient Behavior Learning by Utilizing Estimated State Value of Self and Teammates.- Sensor and Information Fusion Applied to a Robotic Soccer Team.- Omnidirectional Walking Using ZMP and Preview Control for the NAO Humanoid Robot.- RoboCup@Home: Results in Benchmarking Domestic Service Robots.- Connecting the Real World with the Virtual World - Controlling AIBO through Second Life.- A Hybrid Agent Simulation System of Rescue Simulation and USARSim Simulations from Going to Fire-Escape Doors to Evacuation to Shelters.- SSL-Vision: The Shared Vision System for the RoboCup Small Size League.- Heuristic Formation Control in Multi-robot Systems Using Local Communication and Limited Identification.- Cooperative Multi-robot Map Merging Using Fast-SLAM.

Summarization: A large corpus of work in artificial intelligence focuses on planning and learning in arbitrarily stochastic domains. However, these methods require significant computational resources (large transition models, huge amounts of samples) and the resulting representations can hardly be broken into easily understood parts, even for deterministic or near-deterministic domains. This paper focuses on a rule induction method for (near-)deterministic domains, so that an unknown world can be described by a set of short rules with well-defined preconditions and effects given a brief interaction with the environment. The extracted rules can then be used by the agent for decision making. We have selected a multiplayer online game based on the SMAUG MUD server as a model of a near-deterministic domain and used our approach to infer rules about the world, generalising from a few examples. The agent starts with zero knowledge about the world and tries to explain it by generating hypotheses, refining them as they are refuted. The end result is a set of a few meaningful rules that accurately describe the world. A simple planner using these rules was able to perform near optimally in a fight scenario. Παρουσιάστηκε στο: 6th Hellenic Conference on Artificial Intelligence

Game playing has always been considered an intellectual activity requiring a good level of intelligence This paper focuses on Adversarial Tetris, a variation of the well-known Tetris game, introduced at the 3rd International Reinforcement Learning Competition in 2009 In Adversarial Tetris the mission of the player to complete as many lines as possible is actively hindered by an unknown adversary who selects the falling tetraminoes in ways that make the game harder for the player In addition, there are boards of different sizes and learning ability is tested over a variety of boards and adversaries This paper describes the design and implementation of an agent capable of learning to improve his strategy against any adversary and any board size The agent employs MiniMax search enhanced with Alpha-Beta pruning for looking ahead within the game tree and a variation of the Least-Squares Temporal Difference Learning (LSTD) algorithm for learning an appropriate state evaluation function over a small set of features The learned strategies exhibit good performance over a wide range of boards and adversaries.

Summarization: RoboCup is an annual international robotic soccer competition. One of its most popular divisions is the Four-Legged League, whereby each team consists of four fully autonomous Sony AIBO robots and researchers focus solely on software development over a standard robotic platform. To compete successfully each robot needs to address a variety of problems: visual object recognition, legged locomotion, localization, and team coordination. This paper focuses on the problem of visual object recognition and suggests a uniform approach for recognizing the key objects in the RoboCup 2007 field: the two goals, the two beacons (colored landmarks), and the ball. The proposed method processes the color-segmented camera image and delivers the type, as well as an estimate of the distance and the angle with respect to the robot, of each recognized object in the current field of view. Our approach is based on a number of procedures which are used uniformly for all three types of objects: horizontal and vertical scanning of the image, identification of large colored areas through a finite state machine, clustering of colored areas through histograms, formation of a bounding box indicating possible presence of an object, and customized filtering for removing implausible indications. Our approach is compared against the approaches of two RoboCup teams (German Team 2004 and SPQR-Legged 2006) and is shown to be equally good or better in many cases. The proposed approach has been used successfully by Team Kouretes of the Technical University of Crete, Greece during various RoboCup events. Παρουσιάστηκε στο: 5th Hellenic Conference on Artificial Intelligence

Several researchers have recently investigated the connection between reinforcement learning and classification. We are motivated by proposals of approximate policy iteration schemes without value functions which focus on policy representation using classifiers and address policy learning as a supervised learning problem. This paper proposes variants of an improved policy iteration scheme which addresses the core sampling problem in evaluating a policy through simulation as a multi-armed bandit machine. The resulting algorithm offers comparable performance to the previous algorithm achieved, however, with significantly less computational effort. An order of magnitude improvement is demonstrated experimentally in two standard reinforcement learning domains: inverted pendulum and mountain-car., 18 pages, 2 figures, to appear in Machine Learning 72(3). Presented at EWRL08, to be presented at ECML 2008

Summarization: Teams of mobile robots have been recently proposed as effective means of completing complex missions involving multiple tasks spatially distributed over a large area. A central problem in such domains is multi-robot routing, namely the problem of coordinating a team of robots in terms of the locations they should visit and the routes they should follow in order to accomplish their common mission. A typical assumption made in prior work on multi-robot routing is that robots are able to communicate uninterruptedly at all times independently of their locations. In this paper, we investigate the multi-robot routing problem under communication constraints, reflecting on the fact that real mobile robots have a limited range of communication and the requirement that connectivity must remain intact (even through relaying) during the entire mission. We propose four algorithms for this problem, all based on the same reactive framework, ranging from greedy to deliberative approaches. All algorithms are tested in various scenarios implemented using the Player-Stage robot simulation environment. Our results demonstrate that effective multi-robot routing can be achieved even under limited communication range with moderate loss compared to the case of infinite communication range. Παρουσιάστηκε στο: 2008 IEEE International Conference on Robotics and Automation

Summarization: Motivated by recent proposals that view a reinforcement learning problem as a collection of classification problems, we investigate various aspects of policy representation using classifiers. In particular, we derive optimal policies for two standard reinforcement learning domains (inverted pendulum and mountain car) in both deterministic and stochastic versions and we examine their internal structure. We then proceed in an evaluation of the representational ability of a variety of classifiers for these policies, using both a multi-class and a binary formulation of the classification problem. Finally, we evaluate the actual performance of the policies learned by the classifiers in the original control problem as a function of the amount of training examples provided. Our results offer significant insight in making the reinforcement-learning-via-classification technology successfully applicable to hard learning problems. Παρουσιάστηκε στο: 2008 IEEE International Conference on Machine Learning and Applications

Summarization: Robotic prototypes for search and rescue operations tend to imitate crawling and swimming organisms such as snakes, salamanders, worms, and eels. The Chlorochlamys Chloroleucaria larvae move themselves by a unique form of loop-like body changes stabilized by their subterminal grasping tools; we call this kind of motion loop-like locomotion. By combining undulatory locomotion with loop-like locomotion, robotic prototypes may improve their efficiency and flexibility in moving through unstructured environments, while the climbing gaits may step up their gait repertoire. In our research we study the feasibility of robotic loop-like locomotion and we build robotic prototypes with the above capabilities. We model the Chlorochlamys Chloroleucaria as a multi-segment manipulator with grippers at both ends and we study the motion planning problem for loop-like locomotion under physical and environmental constraints. Extensive experimental studies demonstrate the feasibility and show the effectiveness of the proposed approach. Our robotic prototype is proposed as a testbed for realizing loop-like locomotion in the real world. Παρουσιάστηκε στο: 2007 IEEE International Conference on Robotics and Biomimetics

The purpose of this work is studying a corneal asphericity change after a myopic refractive correction by mean of excimer lasers. As the ablation profile shape plays a key role in the post-op corneal asphericity, ablation profiles of recent lasers should be studied. The other task of this research was to analyze operation (LASIK) outcomes of one of the lasers with generic spherical ablation profile and to compare an asphericity change with theoretical predictions. The several correction methods, like custom generated aspherical profiles, may be utilized for mitigation of unwanted effects of asphericity change. Here we also present preliminary results of such correction for one of the excimer lasers.

Brief history and development trends of organic materials based photosensitive devices including home activities in this field are presented. New home-made organic materials are briefly reviewed including DA - BuTAZ, Zn ( OB-pDA), Zn (OBGO)2 , Zn (OBBA)2 PTA. Data are presented for new organic materials optical properties (both photoluminescence and absorption) in the wide spectral range. It's noted that large Stokes shift is generally observed between optical absorption and luminescence bands. Two layer device structures characteristics have been studied. Data are presented for their current-voltage and photoelectric characteristics. It's noted that photosensitivity spectra have complicated character resembling that of absorption its maximum being located in UV spectral region. Comparison between organic and inorganic photodetectors is presented. Several differences are observed namely power-law current-voltage dependence and essential increase of photosensitivity with applied voltage.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Brief history, modern state and development trends of organic electroluminescent structures technology (so-called OLED technology) are reviewed including research activities in this field in Russia. It's noted that OLED technology is one of the most promising newly emerging display technologies. Due to advantages of these devices (low power consumption, potential flexibility, wide color range) it is particularly well suited for small area display applications (micro displays) such as cell phones, virtual imaging systems, portable electronics. Experimental results for homemade blue light emitting OLED structures and hermetically sealed numeric displays are presented including photoluminescence (PL) and electroluminescence (EL ) current-voltage and brightness characteristics. It is noted that visible electroluminescence is observed at ultra low current level of nearly 1 μA, luminous efficiency exceeding 1 lm/W thus being nearly the same as for super bright inorganic inGaN/IGaN LEDs. Special attention is paid for destabilizing factors (temperature and degradation phenomena) influence on device characteristics.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The aim of this paper is to develop the principle aspects of the cost accounting procedure in the tourist enterprises.

Summarization: This paper describes a motion controller which issues incremental velocity commands to a nonholonomic mobile robot guided by a holonomic path planner. The controller finds the best pair of rotational and translational velocities through discrete optimization of a multi-criteria objective function. Valid velocity choices are restricted within the dynamic velocity window as determined by the current velocities and the maximum acceleration and deceleration ability of the robot (smoothness criterion). In addition, for each choice the objective function examines the proximity of the resulting stopping configuration to the current goal set by the planner (accuracy criterion). Finally, it takes into account the potential of unforeseen, perhaps unavoidable, collisions due to dynamic obstacles or due to the holonomic nature of the path planner (safety criterion). The controller issues commands which balance these criteria as determined by the user. The proposed controller has been implemented and tested on a Nomad 200 mobile robot achieving smooth, accurate, and safe motion control both in simulated and in real environments Παρουσιάστηκε στο: 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems

It is shown theoretically, that observed in experiments the strong low threshold feedback in the resonator with a high pressure gas (Xe) cell of the CO2 laser, in which the frequency interval between axial modes is equal to frequency Stokes shift at Stimulated Brillouin Scattering (SBS) in Xe, can arise owing to nondegenerate four-wave mixing in a gas cell on generated as at SBS running phase gratings.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Theoretical propositions of powerful technological CO 2 laser operation with selection and correction of phase of high order cross models have been experimentally studied. The effective transformation with the help of phase corrector of the high order mode oscillations field to the narrow directed beam at the level of output power up to 1kW is reported for the first time. The physical nature of intra-cavity aberrations with negative influence on the beam quality is analyzed. It is shown that the most significant aberrations such as optical wedge arise when we use the cross pumping of active medium and the cross discharge. The prospect of the considered method application to obtain narrow directed radiation is considered at higher power values.

Summarization: Neural maps have been recently proposed as an alternative method for mobile robot path planning. However, these proposals are mostly theoretical and primarily concerned with biological plausibility. This paper addresses the applicability of neural maps to mobile robot navigation with focus on efficient implementations It is suggested that neural maps offer a promising alternative compared to the traditional distance transform and harmonic function methods. Applications of neural maps are presented for both global and local navigation. Experimental results (both simulated and real-world on a Nomad 200 mobile robot) demonstrate the validity of the approach. Our work reveals that a key issue for success of the method is the organization of the map that needs to be optimized for the situation at hand Παρουσιάστηκε στο: e 1999 IEEE International Joint Conference on Neural Networks

New x-ray chemical micro analyzer for the invesitgation of chemical elements spatial distribution and for the element analyis has been designed. Characteristics of a new device and possibilities of its application are considered.