bluuebunny/crossref_metadata_2025 huggingface dataset:
A critical humidity threshold for monsoon transitions
Authors: Schewe J. , Levermann A. , Cheng H.
Published: March 2012

Abstract. Monsoon systems around the world are governed by the so-called moisture-advection feedback. Here we show that, in a minimal conceptual model, this feedback implies a critical threshold with respect to the atmospheric specific humidity qo over the ocean adjacent to the monsoon region. If qo falls short of this critical value qoc, monsoon rainfall over land cannot be sustained. Such a case could occur if evaporation from the ocean was reduced, e.g. due to low sea surface temperatures. Within the restrictions of the conceptual model, we estimate qoc from present-day reanalysis data for four major monsoon systems, and demonstrate how this concept can help understand abrupt variations in monsoon strength on orbital timescales as found in proxy records.
Extrapolating glacier mass balance to the mountain range scale: the European Alps 1900–2100
Authors: Huss M.
Published: March 2012

Abstract. This study addresses the extrapolation of single glacier mass balance measurements to the mountain range scale and aims at deriving time series of area-averaged mass balance and ice volume change for all glaciers in the European Alps for the period 1900–2100. Long-term mass balance series for 50 Swiss glaciers based on a combination of field data and modelling, and WGMS data for glaciers in Austria, France and Italy are used. A complete glacier inventory is available for the year 2003. Mass balance extrapolation is performed based on (1) arithmetic averaging, (2) glacier hypsometry, and (3) multiple regression. Given a sufficient number of data series, multiple regression with variables describing glacier geometry performs best in reproducing observed spatial mass balance variability. Future mass changes are calculated by driving a combined model for mass balance and glacier geometry with GCM ensembles based on four emission scenarios. Mean glacier mass balance in the European Alps is −0.32 ± 0.04 m w.e. a−1 in 1900–2011, and −1 m w.e. a−1 over the last decade. Total ice volume change since 1900 is −100 ± 13 km3; annual values vary between −5.9 km3 (1947) and +3.9 km3 (1977). Mean mass balances are expected to be around −1.3 m w.e. a−1 by 2050. Model results indicate a glacier area reduction to 4–18% relative to 2003 for the end of the 21st century.
Diversity and seasonal variation of phytoplankton community in the Santragachi Lake, West Bengal, India
Authors: Ghosh Subhabrata , Barinova Sophia , Keshri Jai Prakash
Published: March 2012

The study of phytoplankton diversity and its seasonal variation was carried out by sampling water taken from the Santragachi Lake, of West Bengal between November 2009 and July 2010. Various physico-chemical variables were recorded and the correlation of this with phytoplankton density was established using Canonical Correspondence Analysis. This showed that the density of phytoplankton was higher when temperature and nutrients were increased. A total of 29 phytoplankton taxa belonging to Chlorophyta (10), Cyanobacteria (8), Charophyta (5), Bacillariophyta (4), and Euglenozoa (2) were recorded from nine samples taken within the study period. Chlorophyta species dominated mostly in variety and percentage composition while Euglenozoa species representatives had the least expression. Bio-indication showed a low diverse community in the monsoon period with better water quality than in pre- and post-monsoon seasons. Various diversity indices (Shannon–Wiener diversity index, Gleason species richness index, Pielou evenness index, and Naughton dominance index) were used to establish the seasonal variation of phytoplankton. The Shannon–Wiener diversity index was most useful in indicating the trophic status of the water as well as the pollution status, which in this case, depicted a moderate level of pollution of this lake.
Ambient Sulphur Dioxide and Female ED Visits for Migraine
Authors: Szyszkowicz Mieczyslaw , Porada Eugeniusz
Published: March 2012

Ambient sulphur dioxide (SO2) concentrations may affect the number of female emergency department (ED) visits for migraine. ED visits diagnosed as migraine among females in two cities in Canada, Toronto (N=704) and Ottawa (N=3,358), were analyzed. In the study case-crossover design was used. Conditional logistic regression was realized to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) relative to an increase in an interquartile range (IQR, in Toronto IQR=2.9 ppb, in Ottawa IQR=3.9 ppb) of sulphur dioxide. In the constructed conditional logistic regression models, temperature and relative humidity were adjusted in the form of natural splines. In Toronto positive and statistically significant associations of sulphur dioxide with migraine ED visits were obtained: all ages, OR=1.04 (95% CI: 1.00, 1.08); age group [15,  50], OR=1.05 (95% CI: 1.01, 1.09). In Ottawa positive correlations were observed: all ages, OR=1.05 (95% CI: 0.97, 1.13); age group [15,  50], OR=1.06 (95% CI: 0.97, 1.15). The results suggest that female migraine may be affected by ambient sulphur dioxide.
Staphylococcus aureusInfection Induced Oxidative Imbalance in Neutrophils: Possible Protective Role of Nanoconjugated Vancomycin
Authors: Chakraborty Subhankari Prasad , Pramanik Panchanan , Roy Somenath
Published: March 2012

Staphylococcus aureusinfection causes oxidative stress in neutrophils. The immune cells use reactive oxygen species (ROS) for carrying out their normal functions while an excess amount of ROS can attack cellular components that lead to cell damage. The present study was aimed to test the protective role of nanoconjugated vancomycin against vancomycin-sensitiveStaphylococcus aureus(VSSA) and vancomycin-resistantStaphylococcus aureus(VRSA) infection induced oxidative stress in neutrophils. VSSA- and VRSA-infection were developed in Swiss mice by intraperitoneal injection of5×106 CFU/mL bacterial solutions. Nanoconjugated vancomycin was treated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was treated to VSSA and VRSA infected mice at similar dose, respectively, for 10 days. The result reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, and nitrite generation and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group; which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These finding suggests the potential use and beneficial protective role of nanoconjugated vancomycin against VSSA and VRSA infection induced oxidative imbalance in neutrophils.
Design Optimisation of Lower-Bound Buckling Capacities for FRP-Laminated Cylindrical Shells
Authors: Wang Hongtao , Croll James G. A.
Published: March 2012

The imperfection sensitive buckling loads of fibre reinforced polymeric (FRP) composite cylindrical shells under axial compression can be optimised with respect to many material and geometric parameters. Current approaches, using mathematical algorithms to optimise the linearised classical critical loads with respect to many design variables, generally ignore the potential reductions in elastic load carrying capacities that result from the severe sensitivities of buckling loads to the effects of initial imperfections. This paper applies a lower-bound design philosophy called the reduced stiffness method (RSM) to the optimisation design of FRP shell buckling. A physical optimisation in terms of parametric studies is carried out for simply supported, 6-ply symmetric, glass-epoxy circular cylindrical shells under uniform axial load. It is shown that under the guidance of RSM, safe lower-bound buckling loads can be enhanced greatly by choosing appropriate combinations of design parameters. It is demonstrated how this approach encourages the delineation of those components of the shell’s membrane and bending stiffness that are important and those that are unimportant within each of the prospective buckling modes. On this basis, it is argued that the RSM provides not only a safe but also a more rational strategy for better design decision making.
Urban Thematic Mapping by Integrating LiDAR Point Cloud with Colour Imagery
Authors: Guan Haiyan , Li Jonathan , Chapman Michael A.
Published: March 2012

This paper presents an effective approach to integrating airborne lidar data and colour imagery acquired simultaneously for urban mapping. Texture and height information extracted from lidar point cloud is integrated with spectral channels of aerial imagery into an image segmentation process. Then, the segmented polygons are integrated with the extracted geometric features (height information between first- and lastreturn, eigenvalue-based local variation and filtered height data) and spectral features (line segments) into a supervised classifier. The results for two different urban areas in Toronto, Canada, demonstrated that a satisfactory overall accuracy of 84.96% and Kappa of 0.76 were achieved in Scene I, while a building detection rate of 92.11%, comission error of 2.10% and omission error of 9.25% were obtained in Scene II.
Optimal Control and Biomechanics of Ambulation with Spring-Loaded Crunches
Authors: Liu Guangyu , Zhang Yanxin , Xie Sheng-Quan , Xue Anke
Published: March 2012

Standard underarm or forearm crutches have some drawbacks induced by their rigid legs. Spingloaded crutches can reduce the impact effect. However, whether or not they also improve propulsion is an open problem. We formulate a problem of the optimal performance of spring-loaded crutches and propose a numerical approach to solve the problem. Then, the numerical optimal values are incorporated to the innovative design of a pair of spring-loaded crutches. To evaluate the crutches' performance, we have conducted standard biomechanical experiments for a number of male subjects under two conditions: walking with standard crutches and with spring-loaded crutches. Three dimensional kinematic data and ground reaction force were recorded and analysed. It was observed that optimized spring-loaded crutches can efficiently propel the crutch walkers, which conforms to the theory.
A Human-Like Approach Towards Humanoid Robot Footstep Planning
Authors: Ayaz Yasar , Konno Atsushi , Munawar Khalid , Tsujita Teppei , Komizunai Shunsuke , Uchiyama Masaru
Published: March 2012

Humanoid robots posses the unique ability to cross obstacles by stepping over or upon them. However, conventional 2D methods for robot navigation fail to exploit this ability and thus design trajectories only by circumventing obstacles. Recently, global algorithms have been presented that take into account this feature of humanoids. However, due to high computational complexity, most of them are very time consuming. In this paper, we present a novel approach to footstep planning in obstacle cluttered environments that employs a human-like strategy to terrain traversal. Design methodology for obstacle stepping over motion designed for use with this algorithm is also presented. The paper puts forth simulation results of footstep planning as well as experimental results for the stepping over trajectory designed for use with hardware execution of the footstep plan.
Derivative-Free Nonlinear Kalman Filtering for MIMO Dynamical Systems: Application to Multi-DOF Robotic Manipulators
Authors: Rigatos Gerasimos G.
Published: March 2012

The paper proposes derivative-free nonlinear Kalman Filtering for MIMO nonlinear dynamical systems. The considered nonlinear filtering scheme which is based on differential flatness theory extends the class of systems to which Kalman Filtering can be applied without the need for calculation of Jacobian matrices. To deduce if a dynamical system is differentially flat, the following should be examined: (i) the existence of the flat output, which is a variable that can be written as a function of the system's state variables (ii) the system's state variables and the input can be written as functions of the flat output and its derivatives. Nonlinear systems satisfying the differential flatness property can be written in the Brunovsky form via a transformation of their state variables and control inputs. After transforming the nonlinear system to the canonical form it is straightforward to apply the standard Kalman Filter recursion. The performance of the proposed derivative-free nonlinear filtering scheme is tested through simulation experiments on benchmark nonlinear multi-input multi-output dynamical systems, such as robotic manipulators.
The Puller-Follower Control of Compliant and Noncompliant Antagonistic Tendon Drives in Robotic Systems
Authors: Potkonjak Veljko , Svetozarevic Bratislav , Jovanovic Kosta , Holland Owen
Published: March 2012

This paper proposes a new control strategy for noncompliant and compliant antagonistic tendon drives. It is applied to a succession of increasingly complex single-joint systems, starting with a linear and noncompliant system and ending with a revolute, nonlinearly tendon coupled and compliant system. The last configuration mimics the typical human joint structure, used as a model for certain joints of the anthropomimetic robot ECCEROBOT. The control strategy is based on a biologically inspired puller-follower concept, which distinguishes the roles of the agonist and antagonist motors. One actuator, the puller, is considered as being primarily responsible for the motion, while the follower prevents its tendon from becoming slack by maintaining its tendon force at some non-zero level. Certain movements require switching actuator roles; adaptive co-contraction is used to prevent tendons slackening, while maintaining energetic efficiency. The single-joint control strategy is then evaluated in a multi-joint system. Dealing with the gravitational and dynamic effects arising from the coupling in a multi-joint system, a robust control design has to be applied with on-line gravity compensation. Finally, an experiment corresponding to object grasping is presented to show the controller's robustness to external disturbances.
Assembly and Disassembly Planning by using Fuzzy Logic & Genetic Algorithms
Authors: Galantucci L. M. , Percoco G. , Spina R.
Published: March 2012

The authors propose the implementation of hybrid Fuzzy Logic-Genetic Algorithm (FL-GA) methodology to plan the automatic assembly and disassembly sequence of products. The GA-Fuzzy Logic approach is implemented onto two levels. The first level of hybridization consists of the development of a Fuzzy controller for the parameters of an assembly or disassembly planner based on GAs. This controller acts on mutation probability and crossover rate in order to adapt their values dynamically while the algorithm runs. The second level consists of the identification of the optimal assembly or disassembly sequence by a Fuzzy function, in order to obtain a closer control of the technological knowledge of the assembly/disassembly process. Two case studies were analyzed in order to test the efficiency of the Fuzzy-GA methodologies.
One-Chip Solution to Intelligent Robot Control: Implementing Hexapod Subsumption Architecture Using a Contemporary Microprocessor
Authors: Pashenkov Nikita , Iwamasa Ryuichi
Published: March 2012

This paper introduces a six-legged autonomous robot managed by a single controller and a software core modeled on subsumption architecture. We begin by discussing the features and capabilities of IsoPod, a new processor for robotics which has enabled a streamlined implementation of our project. We argue that this processor offers a unique set of hardware and software features, making it a practical development platform for robotics in general and for subsumption-based control architectures in particular. Next, we summarize original ideas on subsumption architecture implementation for a six-legged robot, as presented by its inventor Rodney Brooks in 1980's. A comparison is then made to a more recent example of a hexapod control architecture based on subsumption. The merits of both systems are analyzed and a new subsumption architecture layout is formulated as a response. We conclude with some remarks regarding the development of this project as a hint at new potentials for intelligent robot design, opened up by a recent development in embedded controller market.
Real-Time Simulation of Robot Controlled Belt Grinding Processes of Sculptured Surfaces
Authors: Zhang Xiang , Cabaravdic Malik , Kneupner Klaus , Kuhlenkoetter Bernd
Published: March 2012

Industrial robots are introduced to belt grinding processes of free-formed surface with elastic wheel nowadays in order to obtain high quality product and high efficiency. However, it is a laborious task to plan grinding paths and write programs for the robot. To release people from it partially, it is necessary to simulate the belt grinding processes which are useful for path generating and dynamic robot control. In this paper, we present a framework of the robot controlled belt grinding simulation system and some key issues in it. We enhance the global removal model to local process model, which can simulate the grinding process more exactly. We also point out the bottleneck of the real-time simulation and put forward a neural network based regression method to meet this difficulty. At the end of the paper, some simple simulation examples are given.
Coevolution Based Adaptive Monte Carlo Localization (CEAMCL)
Authors: Ronghua Luo , Bingrong Hong
Published: March 2012

An adaptive Monte Carlo localization algorithm based on coevolution mechanism of ecological species is proposed. Samples are clustered into species, each of which represents a hypothesis of the robot's pose. Since the coevolution between the species ensures that the multiple distinct hypotheses can be tracked stably, the problem of premature convergence when using MCL in highly symmetric environments can be solved. And the sample size can be adjusted adaptively over time according to the uncertainty of the robot's pose by using the population growth model. In addition, by using the crossover and mutation operators in evolutionary computation, intra-species evolution can drive the samples move towards the regions where the desired posterior density is large. So a small size of samples can represent the desired density well enough to make precise localization. The new algorithm is termed coevolution based adaptive Monte Carlo localization (CEAMCL). Experiments have been carried out to prove the efficiency of the new localization algorithm.
On Algorithms for Planning S-Curve Motion Profiles
Authors: Nguyen Kim Doang , Ng Teck-Chew , Chen I-Ming
Published: March 2012

Although numerous researches on s-curve motion profiles have been carried out, up to date, no systematic investigation on the general model of polynomial s-curve motion profiles is considered. In this paper, the model of polynomial s-curve motion profiles is generalized in a recursive form. Based on that, a general algorithm to design s-curve trajectory with time-optimal consideration is proposed. In addition, a special strategy for planning s-curve motion profiles using a trigonometric model is also presented. The algorithms are implemented on a linear motor system. Experimental results show the effectiveness and promising application ability of the algorithms in s-curve motion profiling.
Mechanical Implementation and Simulation of MoboLab, A Mobile Robot for Inspection of Power Transmission Lines
Authors: Nayyerloo Mostafa , Yeganehparast Seyyed Mohammad Mehdi , Barati Alireza , Foumani Mahmud Saadat
Published: March 2012

This paper describes the first phase in development of a mobile robot that can navigate aerial power transmission lines completely unattended by human operator. Its ultimate purpose is to automate inspection of power transmission lines and their equipments.

The authors have developed a scaled functional model of such a mobile robot with a preliminary simple computer based on-off controller.

MoboLab (Mobile Laboratory) navigates a power transmission line between two strain towers. It can maneuver over obstructions created by line equipments such as insulators, warning spheres, dampers, and spacer dampers. It can also easily negotiate the towers by its three flexible arms. MoboLab has an internal main screw which enables the robot to move itself or its two front and rear arms independently through changing gripped points. When the front arm gets close to an obstacle, the arm detaches from the line and goes down, the robot moves forward, the arm passes the obstacle and grippes the line again. In a same way another arms pass the obstacle.
Workspace Topologies of Industrial 3R Manipulators
Authors: Ottaviano Erika , Ceccarelli Marco , Husty Manfred
Published: March 2012

A mathematical analysis is used to characterize workspace topologies of industrial 3R manipulators. A level-set reconstruction of the workspace is formulated to identify characteristic points with fairly simple algebraic expressions. Thus, industrial 3R manipulators are classified as functions of workspace kinematic properties. Examples are illustrated to show practical usefulness of the proposed workspace characterization.
Optical Flow Based Robot Obstacle Avoidance
Authors: Souhila Kahlouche , Karim Achour
Published: March 2012

In this paper we try to develop an algorithm for visual obstacle avoidance of autonomous mobile robot. The input of the algorithm is an image sequence grabbed by an embedded camera on the B21r robot in motion. Then, the optical flow information is extracted from the image sequence in order to be used in the navigation algorithm. The optical flow provides very important information about the robot environment, like: the obstacles disposition, the robot heading, the time to collision and the depth. The strategy consists in balancing the amount of left and right side flow to avoid obstacles, this technique allows robot navigation without any collision with obstacles. The robustness of the algorithm will be showed by some examples.
Modeling and Simulation of Elementary Robot Behaviors using Associative Memories
Authors: Touzet Claude F.
Published: March 2012

Today, there are several drawbacks that impede the necessary and much needed use of robot learning techniques in real applications. First, the time needed to achieve the synthesis of any behavior is prohibitive. Second, the robot behavior during the learning phase is – by definition – bad, it may even be dangerous. Third, except within the lazy learning approach, a new behavior implies a new learning phase. We propose in this paper to use associative memories (self-organizing maps) to encode the non explicit model of the robot-world interaction sampled by the lazy memory, and then generate a robot behavior by means of situations to be achieved, i.e., points on the self-organizing maps. Any behavior can instantaneously be synthesized by the definition of a goal situation. Its performance will be minimal (not necessarily bad) and will improve by the mere repetition of the behavior.
CoRoBa, a Multi Mobile Robot Control and Simulation Framework
Authors: Colon Eric , Sahli Hichem , Baudoin Yvan
Published: March 2012

This paper describes on-going development of a multi robot control framework named CoRoBa. CoRoBa is theoretically founded by reifying Real Time Design Patterns. It uses CORBA as its communication Middleware and consequently benefits from the interoperability of this standard. A multi-robot 3D simulator written in Java3D integrates seamlessly with this framework. Several demonstration applications have been developed to validate the design and implementation options.
Communication Patterns as Key towards Component-Based Robotics
Authors: Schlegel Christian
Published: March 2012

Vital functions of mobile robots are provided by software and software dominance is still growing. Mastering the software complexity is not only a demanding but also indispensable task towards an operational robot. Nevertheless, well-known and even always needed algorithms are often implemented from scratch over and over again instead of being reused as off-the-shelf components. A major reason is the lack of a framework that allows to compose robotics software out of standardized components without already prescribing a robotics architecture. Whereas Component Based Software Engineering (CBSE) is an approach to make a shift from implementation to composition, the general CBSE approach does not give any hints on how to ensure that independently provided components finally fit together as reusable components. This paper introduces a small set of communication patterns as basis for all intercomponent interactions. Since all externally visible interfaces of components are composed out of the same set of communication patterns, these are the key towards a stringent interface semantics. Generic communication patterns enforce decoupling of components and ensure composability by restricting the diversity of interfaces. The SmartSoft framework as one implementation of this approach already proved its adequacy in many projects.
Software Systems for Robotics An Applied Research Perspective
Authors: Broten Greg , Monckton Simon , Giesbrecht Jared , Collier Jack
Published: March 2012

Over the past 20 years, Defence Research and Development Canada has developed numerous tele-operated unmanned ground vehicles (UGV), many founded on the ANCÆUS command and control system. This paper relates how long experience with tele-operated UGVs influenced DRDC's shift in focus from tele-operated to autonomous unmanned vehicles (UV), the forces that guided DRDC's development approach and DRDC's experience adapting a specific tool set, MIRO, to a UGV implementation.
Control a 2-Axis Servomechanism by Gesture Recognition Using a Generic WebCam
Authors: Tavares J. M. R. S. , Ferreira R. , Freitas F.
Published: March 2012

This paper presents two approaches used to control a 2-axis servomechanism by gesture recognition. For both approaches, the adopted control philosophy was: In the system's learning phase, the control images are acquired by a generic webcam and associated to the desired orders. On the other hand, in the working phase, each control image is acquired, by the same webcam and, by comparison with the stored orders images, the desired order is recognized and processed by the servomechanism in quasi real time. In this paper, the used servomechanism and both implemented approaches are described, and are indicated some advantages and weakness of each one. Two examples of images control sets are also presented, and some conclusions and future works are addressed.
Audit, Control and Monitoring Design Patterns (ACMDP) for Autonomous Robust Systems (ARS)
Authors: Trad A. , Trad C.
Published: March 2012

This paper proposes the Audit, Control and Monitoring Design Patterns (ACMDP) for building Autonomous and Robust Systems (ARS) such as Mobile Robot Systems (MRS). These patterns are also applicable to other Mission Critical and Complex Systems (MCCS). This paper presents a proposal which will help ARS project managers and engineers design, build and estimate the probability that an ARS will succeed or fail. Furthermore, this proposal offers the possibility to ARS problems with the help of audit, monitoring and controlling components, adjust the project management pathways, and define the problem sources as well as their possible solutions, in order to deliver an ARS or an MRS.
Nonlinear Receding-Horizon Control of Rigid Link Robot Manipulators
Authors: Hedjar R. , Boucher P.
Published: March 2012

The approximate nonlinear receding-horizon control law is used to treat the trajectory tracking control problem of rigid link robot manipulators. The derived nonlinear predictive law uses a quadratic performance index of the predicted tracking error and the predicted control effort. A key feature of this control law is that, for their implementation, there is no need to perform an online optimization, and asymptotic tracking of smooth reference trajectories is guaranteed. It is shown that this controller achieves the positions tracking objectives via link position measurements. The stability convergence of the output tracking error to the origin is proved. To enhance the robustness of the closed loop system with respect to payload uncertainties and viscous friction, an integral action is introduced in the loop. A nonlinear observer is used to estimate velocity. Simulation results for a two-link rigid robot are performed to validate the performance of the proposed controller.
An Agent-Based Manufacturing Management System for Production and Logistics within Cross-Company Regional and National Production Networks
Authors: Heinrich S. , Durr H. , Hanel T. , Lassig J.
Published: March 2012

The goal is the development of a simultaneous, dynamic, technological as well as logistical real-time planning and an organizational control of the production by the production units themselves, working in the production network under the use of Multi-Agent-Technology. The design of the multi-agent-based manufacturing management system, the models of the single agents, algorithms for the agent-based, decentralized dispatching of orders, strategies and data management concepts as well as their integration into the SCM, basing on the solution described, will be explained in the following.
Social Odometry: Imitation Based Odometry in Collective Robotics
Authors: Gutiérrez Álvaro , Campo Alexandre , Santos Francisco C. , Monasterio-Huelin Félix , Dorigo Marco
Published: March 2012

The improvement of odometry systems in collective robotics remains an important challenge for several applications. Social odometry is an online social dynamics which confers the robots the possibility to learn from the others. Robots neither share any movement constraint nor access to centralized information. Each robot has an estimate of its own location and an associated confidence level that decreases with distance traveled. Social odometry guides a robot to its goal by imitating estimated locations, confidence levels and actual locations of its neighbors. This simple online social form of odometry is shown to produce a self-organized collective pattern which allows a group of robots to both increase the quality of individuals' estimates and efficiently improve their collective performance.
A Tethering Device for Mobile Robot Guidance
Authors: Na Sangik , Ahn Hyo-Sung , Lee Yu-Cheol , Yu Wonpil
Published: March 2012

A new human and robot interface tool, so-called Navi-Guider, which makes it easy to handle mobile robots, is presented in this paper. The Navi-Guider is easily mounted on a mobile robot and is able to detect a length and a direction of the tether pulled out by a user. Those detected factors are utilized for the robot guidance and control. This paper addresses detailed hardware and software architecture of the Navi-Guider and demonstrates the practical usability of the system through actual experimental tests. The new device, Navi-Guider, is an intuitive control tool for moving mobile robots from a place to another place just by pulling the tether.
SLAM-based Cross-a-Door Solution Approach for a Robotic Wheelchair
Authors: Cheein Fernando A. Auat , De La Cruz Celso , Bastos Teodiano F. , Carelli Ricardo
Published: March 2012

This paper proposes a solution to the cross-a-door problem in unknown environments for a robotic wheelchair commanded through a Human-Machine Interface (HMI). The problem is solved by a dynamic path planning algorithm implementation based on successive frontier points determination. An adaptive trajectory tracking control based on the dynamic model of the robotic wheelchair is implemented on the vehicle to direct the wheelchair motion along the path in a smooth movement. An EKF feature-based SLAM is also implemented on the vehicle which gives an estimate of the wheelchair pose inside the environment. The SLAM allows the map reconstruction of the environment for safe navigation purposes. The whole system steers satisfactorily the wheelchair with smooth movements through common doorways which are narrow considering the size of the vehicle. Implementation results validating the proposal are also shown in this work.
Hybrid Collaborative Stereo Vision System for Mobile Robots Formation
Authors: Roberti Flavio , Toibero Juan Marcos , Soria Carlos , Vassallo Raquel Frizera , Carelli Ricardo
Published: March 2012

This paper presents the use of a hybrid collaborative stereo vision system (3D-distributed visual sensing using different kinds of vision cameras) for the autonomous navigation of a wheeled robot team. It is proposed a triangulation-based method for the 3D-posture computation of an unknown object by considering the collaborative hybrid stereo vision system, and this way to steer the robot team to a desired position relative to such object while maintaining a desired robot formation. Experimental results with real mobile robots are included to validate the proposed vision system.
Fault-tolerant Control of Unmanned Underwater Vehicles with Continuous Faults: Simulations and Experiments
Authors: Liu Qian , Zhu Daqi
Published: March 2012

A novel thruster fault diagnosis and accommodation method for open-frame underwater vehicles is presented in the paper. The proposed system consists of two units: a fault diagnosis unit and a fault accommodation unit. In the fault diagnosis unit an ICMAC (Improved Credit Assignment Cerebellar Model Articulation Controllers) neural network information fusion model is used to realize the fault identification of the thruster. The fault accommodation unit is based on direct calculations of moment and the result of fault identification is used to find the solution of the control allocation problem. The approach resolves the continuous faulty identification of the UV. Results from the experiment are provided to illustrate the performance of the proposed method in uncertain continuous faulty situation.
Robot-Assisted Risky Intervention, Search, Rescue and Environmental Surveillance
Authors: Habib Maki K. , Baudoin Yvan
Published: March 2012

Technology has become the solution to many long-standing problems, and while current technologies may be effective, it is far from fully addressing the hug, complex, difficult and challenging tasks associated with disaster missions and risky intervention. The challenge is in finding creative, reliable and applicable technical solutions in such highly constrained and uncertain environment. In addition, it is necessary to overcome constrains on resources by developing innovative, cost effective and practical technology. Robotics can play important intelligent and technological roles that support first response equipment in harsh and dangerous environments while replacing rescue personnel from entering unreachable or unsafe places. Robotics solutions that are well adapted to local conditions of unstructured and unknown environment can greatly improve safety and security of personnel as well as work efficiency, productivity and flexibility. Solving and fulfilling the needs of such tasks presents challenges in robotic mechanical structure and mobility, sensors and sensor fusion, autonomous and semi autonomous control, planning and navigation, and machine intelligence. This paper categorizes the source of disasters and associated missions, and highlights the needs for suitable and reliable technology and technical and functional requirements of robotic systems to fulfill task objectives. In addition, it shows that robotic technologies can be used for disasters prevention or early warning, intervention and recovery efforts during disasters with all possible kinds of relevant missions while ensuring quality of service and safety of human beings. Some of these missions may include: demining, search and rescue, surveillance, reconnaissance and risk assessment, evacuation assistance, intrusion/victim detection and assessment, etc.
Indoles via Palladium‐Catalyzed Cyclization
Authors: Cacchi Sandro , Fabrizi Giancarlo , Goggiamani Antonella
Published: March 2012

The palladium‐catalyzed assembly of the functionalized pyrrole nucleus on a benzenoid scaffold is a widley used synthetic tool for the preparation of indole derivatives. This construction can be categorized into four main types: (1) cyclization of alkynes; (2) cyclization of alkenes; (3) cyclization viaC‐vinyl reactions; and (4) cyclization viaN − arylation orN − vinylation reactions. The first approach is the most versatile in terms of range of the added functional groups and of the bonds that can be created in the construction of the pyrrole ring. This method is based on the utilization of precursors containing nitrogen nucleophiles and carbon‐carbon triple bonds. The nitrogen nucleophile and alkyne moiety may be part of the same molecule or belong to two different molecules. Some of the most general cyclizations of indoles are summarized. Alkene‐based cyclizations to give indoles are also summarized. Cyclization to indoles via arene vinylation has limited synthetic scope. Indoles can be prepared via cyclizations proceeding throughN‐arylation and N‐vinylation reactions based on pioneering work. In general, only synthetic procedures where palladium catalysis is involved in the pryrrole ring construction event are discussed in this chapter.
Reactive Extrusion of Polymers
Authors: Tzoganakis Costas , Zhu Shuihan
Published: March 2012

Reactive extrusion (REX) is a process that combines the mass and heat transport operations with simultaneous chemical reactions taking place inside the extruder for the purpose of modifying the properties of existing polymers or for producing new ones. REX is increasingly becoming a powerful technique to develop and fabricate a variety of novel polymeric materials in a highly efficient and flexible way. This combination of chemical reactions and transport phenomena in an extruder provides a large opportunity window for fast prototyping a plethora of specialty polymers filling in the end‐use gaps among the existing commercial resins and natural products. A very large amount of literature on REX has been accumulated over the past few decades, and this review addresses some of the most recent publications while earlier references can be found in previous literature reviews.
Evaporative‐Based Detectors as Global Response Instruments
Authors: Márquez Sillero Isabel , Cárdenas Aranzana Ma Soledad
Published: March 2012

Evaporative‐based detectors are a new generation of instruments, which provide a universal response for a wide variety of compounds or their families whose determination by other conventional detection systems is limited by different reasons. Both evaporative light scattering detector (ELSD) and corona‐charged aerosol detector (C‐CAD) have been recognized as global response detectors in liquid and supercritical chromatographies. Their advantage over optical or electrochemical detectors is that they do not require from the analytes to present special physicochemical properties. The evaporative‐based detectors nebulized the mobile‐phase/liquid stream effluent, producing analyte particles that are optically detected through the scattered light in the case of ELSD or by charge transfer in the case of the C‐CAD. The foundation of the detection and the main applications of these detectors will be deeply commented in this article. Moreover, a comparison with conventional detectors (ultraviolet/visible (UV/VIS), refractive index (RI), and mass spectrometers (MSs)) is included. In the light of the bibliography available on this topic, future applications of and perspectives on the use of these detectors can also be anticipated.
Developing Genetically Engineered Mouse Models to Study Tumor Suppression
Authors: Xiong Shunbin , Parker‐Thornburg Jan , Lozano Guillermina
Published: March 2012

Since the late 1980s, the tools to generate mice with deletions of tumor suppressors have made it possible to study such deletions in the context of a whole animal. Deletion of some tumor suppressors results in viable mice while deletion of others yield embryo lethal phenotypes, cementing the concept that genes that often go awry in cancer are also of developmental importance. More sophisticated mouse models were subsequently developed to delete a gene in a specific cell type at a specific time point. Additionally, incorporation of point mutations in a specific gene as observed in human tumors has also revealed their contributions to tumorigenesis. On the other hand, some models never develop cancer unless combined with other deletions, suggesting a modifying role in tumorigenesis. This review will describe the technical aspects of generating these mice and provide examples of the outcomes obtained from alterations of different tumor suppressors. Curr. Protoc. Mouse Biol. 2:9‐24 © 2012 by John Wiley & Sons, Inc.
Rituximab or a second anti–tumor necrosis factor therapy for rheumatoid arthritis patients who have failed their first anti–tumor necrosis factor therapy? Comparative analysis from the British Society for Rheumatology Biologics Register
Authors: Soliman Moetaza M. , Hyrich Kimme L. , Lunt Mark , Watson Kath D. , Symmons Deborah P. M. , Ashcroft Darren M. ,   on behalf of the British Society for Rheumatology Biologics Register
Published: March 2012

Objective

To compare the effectiveness of rituximab (RTX) or a second anti–tumor necrosis factor (anti‐TNF) therapy in rheumatoid arthritis (RA) patients who had failed their first anti‐TNF and switched to either RTX or a second anti‐TNF, in routine clinical practice.

Methods

RA patients were registered with the British Society for Rheumatology Biologics Register. Response to treatment 6 months after switching was assessed using European League Against Rheumatism (EULAR) criteria and improvements in a Health Assessment Questionnaire (HAQ) score (0.22 unit or more). Regression analyses were used to compare EULAR response and improvement in HAQ score between the 2 groups, adjusting for propensity scores.

Results

In total, 1,328 patients were included in the analysis of EULAR response, and 937 patients were included in the analysis of HAQ scores. Six months after switching, 54.8% of patients who switched to RTX were EULAR responders compared to 47.3% of those who switched to a second anti‐TNF. A total of 38.4% of RTX patients achieved a clinically important improvement in HAQ score compared to 29.6% in anti‐TNF patients. After adjustment using propensity scores, patients who switched to RTX were significantly more likely to achieve EULAR response (odds ratio [OR] 1.31; 95% confidence interval [95% CI] 1.02, 1.69) compared to those who switched to an alternative anti‐TNF. RTX patients were also significantly more likely to achieve improvements in HAQ score (OR 1.49; 95% CI 1.07, 2.08).

Conclusion

The results suggest that switching to RTX may be of more benefit than switching to an alternative anti‐TNF therapy after failing the first anti‐TNF therapy in RA patients.
Identifying generic predictors of outcome in patients presenting to primary care with nonspinal musculoskeletal pain
Authors: Henschke Nicholas , Ostelo Raymond W. J. G. , Terwee Caroline B. , van der Windt Danielle A. W. M.
Published: March 2012

Objective

To identify which generic prognostic factors, such as pain intensity, levels of disability, and psychological factors, are most strongly associated with outcome from musculoskeletal pain, regardless of the location of pain. We tested the hypothesis that pain location does not add predictive value to these generic prognostic models, and that such prognostic factors are equally important across different pain locations.

Methods

Data from a prospective observational cohort of primary care patients with acute (n = 413) and chronic (n = 414) nonspinal musculoskeletal pain were used to develop predictive models. The analysis was carried out in 3 steps: derivation of predictive models including generic factors only, investigation of the added predictive value of pain location, and investigation of effect modification by pain location.

Results

Generic factors predicted outcome over different time periods (3 months and 12 months) and for both acute and chronic musculoskeletal pain (area under the receiver operating characteristic curve 0.73–0.75). The most consistent predictors of poor outcome were having had the same complaint in the previous year (odds ratio range 2.03–3.46), a lower level of education, lower scores on the Short Form 36 vitality subscale, using pain medication at baseline, and being bothered by the complaint more often in the past 3 months. Pain location variables only slightly improved the predictive ability of the models over generic factors and were inconsistent across the models.

Conclusion

Generic factors appear to play an important role in the prognosis of acute and chronic nonspinal musculoskeletal pain, regardless of the location of pain.
Ultrasonographic hand features in systemic sclerosis and correlates with clinical, biologic, and radiographic findings
Authors: Elhai Muriel , Guerini Henri , Bazeli Ramin , Avouac Jerôme , Freire Véronique , Drapé Jean‐Luc , Kahan André , Allanore Yannick
Published: March 2012

Objective

To investigate ultrasonographic (US) hand features in systemic sclerosis (SSc) patients and their relationship with clinical, biologic, and radiographic data.

Methods

Fifty‐two consecutive SSc patients were included in a cross‐sectional observational study together with 24 rheumatoid arthritis (RA) patients enrolled as controls. All patients underwent clinical examination, including tender and swollen joint counts, measurement of disability indices, and hand/wrist radiographs. US was performed on the hand and wrist joints and was aimed at the detection of synovitis, tenosynovitis, and calcinosis.

Results

Synovitis and tenosynovitis were more frequently detected with US in SSc patients (46% and 27%, respectively) than with clinical examination (15% and 6%, respectively; P < 0.01 for both comparisons). Fifty‐seven percent of patients had inflammatory synovitis (mostly Doppler grade 1), and tenosynovitis was either inflammatory or fibrotic. Calcifications were observed using US and radiographs in 40% and 36% of SSc patients, respectively (P = 0.8). As compared to RA, US features specific to SSc were sclerosing tenosynovitis (P < 0.01) and soft tissue calcifications (P = 0.01).

Conclusion

Our study confirms that articular involvement in SSc is underestimated by a single clinical examination. It is characterized by mild inflammatory changes and the specific findings include sclerotic US aspects together with calcinosis. Further prospective studies are warranted to evaluate the predictive value of these findings and determine whether they should be considered for adapting a therapeutic strategy.