bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptive Human-Aware Robot Navigation in Close Proximity to Humans
Authors: Svenstrup Mikael , Hansen Søren Tranberg , Andersen Hans Jørgen , Bak Thomas 
Published: March 2012

For robots to be able coexist with people in future everyday human environments, they must be able to act in a safe, natural and comfortable way. This work addresses the motion of a mobile robot in an environment, where humans potentially want to interact with it. The designed system consists of three main components: a Kalman filter-based algorithm that derives a person's state information (position, velocity and orientation) relative to the robot; another algorithm that uses a Case-Based Reasoning approach to estimate if a person wants to interact with the robot; and, finally, a navigation system that uses a potential field to derive motion that respects the person's social zones and perceived interest in interaction. The operation of the system is evaluated in a controlled scenario in an open hall environment. It is demonstrated that the robot is able to learn to estimate if a person wishes to interact, and that the system is capable of adapting to changing behaviours of the humans in the environment.
Design History and Advantages of a New Lever-Propelled Wheelchair Prototype
Authors: Sarraj Ahmad Rifai , Massarelli Raphael 
Published: March 2012

Wheelchair propulsion has been reported to be responsible for musculoskeletal pain in the upper extremities. Epidemiological studies have shown a high prevalence of shoulder complaints in paraplegic and quadriplegic spinal cord injured (SCI) people. It has been argued that the high incidence of shoulder complaints in SCI was the result of the weight-bearing or propulsion function of the upper extremity in those subjects. This work aimed at proposing an alternative wheelchair propulsion technique based on the levers' system. The interface prototype-users, the wheelchair skills evaluation, the oxygen uptake and the cardiac frequency are investigated by an objective and subjective studies. Our prototype is designed to be an attempt in the field of disabled athletes having some advantages of a non-conventional manual wheelchair propulsion technique, avoiding complications induced by the conventional one.
Landing Motion Control of Articulated Hopping Robot
Authors: Sung Sanghak , Youm Youngil 
Published: March 2012

This paper deals with the landing motion of an articulated legged robot. Humans use a peculiar crouching motion to land safely which can be characterized by body stiffness and damping. A stiffness controller formulation is used to realize this human behavior for the robot. Using this method, the landing motion is achieved with only the desired body stiffness and damping values, without desired COG(Center of Gravity) or joint paths. To achieve soft landing, variable body stiffness and damping values were optimized. PBOT, which has four links with flexible joints was used for validation of the landing controller. A body stiffness and damping controller was used as an outer landing control loop and a fast subsystem controller for flexible joints was used as an inner force control loop. Simulations and experimental results about the landing motion are presented to show the performance of the body stiffness and damping controller.
Power Tillers for Demining: Blast Test
Authors: Cepolina Emanuela Elisa , Hemapala Manjula Udayanga 
Published: March 2012

Power tillers are very simple and versatile machines with large scale diffusion in developing countries, where they are commonly used both for agriculture and for transportation purposes. A new integrated participatory approach that makes use of and improves local end-users knowledge has been used to design a new robotic system for humanitarian demining applications in Sri Lanka, using power tiller as core module. A demining machine composed by a tractor unit, a ground processing tool and a vegetation cutting tool is here presented together with results obtained from the first blast test on the preliminary version of tractor unit armouring. Different breakable connections between wheels and axle have been designed to cause physical detachment and interrupt the transmission of the shock wave released by the explosion of a mine under one wheel. Effects of explosions on different types of wheels and on the chassis have been recorded and commented.
Task Characterisation and Cross-Platform Programming Through System Identification
Authors: Kyriacou Theocharis , Nehmzow Ulrich , Iglesias Roberto , Billings Steve 
Published: March 2012

Developing robust and reliable control code for autonomous mobile robots is difficult, because the interaction between a physical robot and the environment is highly complex, it is subject to noise and variation, and therefore partly unpredictable. This means that to date it is not possible to predict robot behaviour, based on theoretical models. Instead, current methods to develop robot control code still require a substantial trial-and-error component to the software design process. Such iterative refinement could be reduced, we argue, if a more profound theoretical understanding of robot-environment interaction existed. In this paper, we therefore present a modelling method that generates a faithful model of a robot's interaction with its environment, based on data logged while observing a physical robot's behaviour. Because this modelling method — nonlinear modelling using polynomials — is commonly used in the engineering discipline of system identification, we refer to it here as “robot identification”. We show in this paper that using robot identification to obtain a computer model of robot-environment interaction offers several distinct advantages: Very compact representations (one-line programs) of the robot control program are generated The model can be analysed, for example through sensitivity analysis, leading to a better understanding of the essential parameters underlying the robot's behaviour, and The generated, compact robot code can be used for cross-platform robot programming, allowing fast transfer of robot code from one type of robot to another. We demonstrate these points through experiments with a Magellan Pro and a Nomad 200 mobile robot.
A Novel Exploration Algorithm Based on a Improvement Strategy
Authors: Gartshore Rachel , Palmer Phil , Illingworth John 
Published: March 2012

In this paper we present a strategy for the problem of exploring an unknown 2D environment. Existing techniques can be methodical, goal oriented or non-reactive to additional knowledge received at each new viewpoint. We present an approach which is not goal driven, but rather seeks new unseen areas to view and explore. The novelty of the strategy presented is the use of a view-improvement technique along with an optimal viewpoint planning method for the calculation and selection of the next-best-viewpoint. The strategy is designed for a sensor system with a limited field-of-view. Example explorations are presented and we demonstrate that the strategy finds new areas to view without exhaustive searching.
Metathesis Polymerization
Authors: Nuyken Oskar , Schneider Martin , Frenzel Ulrich 
Published: March 2012

AbstractEspecially since the turn of the century, metathesis has become one of the most attractive developments in organic synthesis, particularly for the synthesis of polymers. A major reason for this has been the discovery of a wide range of new catalysts. The development of Ru‐based catalysts has opened up new avenues of synthesis due to their functional group tolerance. It this review, homogeneous, heterogeneous, and immobilized catalysts are described. It is shown that13C NMR spectroscopy is a valuable tool for the evaluation of the microstructure of polymers synthesized from bicyclic monomers, such as norbornene and its derivatives. Acyclic diene metathesis polymerization (ADMET) is also addressed. Indeed, the intermolecular reaction of α,ω‐dienes yielding ethene has become increasingly important over the past 10 years. Degradation of polymers via cross‐metathesis of unsaturated polymers with olefins can be used for analytical purposes and for the design of tailor‐made polymers. This article also discuses about the growing interest in terminally functionalized polymers and oligomers. Synthetic strategies based on metathesis reactions are discussed in some detail. The section titled Macromolecular Engineering summarizes trends in polymer chemistry involving metathesis polymerization combined with other chain growth mechanisms to synthesize block and graft copolymers with novel molecular structures. In addition, this article details synthetic routes to advanced materials based on ring‐opening metathesis polymerization (ROMP). Furthermore, some of the industrial polymers synthesized via ROMP are introduced and discussed in some detail. This review concludes with a discussion on mono‐, bi‐, and tri‐cyclic monomers and their ring‐opening polymerizations.
Single‐Site Catalysts
Authors: Heurtefeu Bertrand , Vaultier Florent , Leino Reko , Boisson Christophe , Cramail Henri 
Published: March 2012

AbstractThe recent rapid development of organometallic single‐site catalysts (SSCs) has revolutionized polyolefin research and permitted the production of new specialty polymers and commodity polyolefins with improved properties. These well‐defined catalyst systems generally consist of a transition metal atom, such as titanium, zirconium, hafnium, iron, nickel, or palladium, complexed with an organic ligand set and an initiating group. In most cases, activation with methylaluminoxane or compounds bearing a weakly coordinating anions generates cationic‐active species responsible for olefin coordination and polymer chain growth. Representative examples of SSCs include the bis(cyclopentadienyl) or bis(phenoxyimine)‐type group 4 catalysts as well as the diimine complexes of nickel and palladium. By variation of the organic ligand and thus the steric and electronic environment of the metal center, these catalysts can be tailored to control the olefin polymerization reaction in an unprecedented fashion. Almost any vinyl monomer, irrespective of molecular weight or steric hindrance, can be polymerized by choosing the proper catalyst. Virtually all feasible poly(α‐olefin) microstructures ranging from atactic to isotactic, hemiisotactic, syndiotactic, and stereoblock polymers can be produced by rational modification of the catalyst structure. Functional monomers are readily copolymerized with the less oxophilic late transition metal catalysts. Entirely new materials, not accessible with traditional Ziegler–Natta catalysts, have emerged, including high melting syndiotactic polystyrene and cycloaliphatic polymers. This article provides a broad overview of SSCs and their application in olefin polymerization. Evolution and classification of SSCs, polymerization of ethylene, propylene, as well as functional olefins, macromolecular architecture bearing polyolefin blocks are covered. Finally, heterogenization of SSCs for use in industrial processes is described.
DNA
Immobilization
Authors: Wittmann Christine , Marquette Christophe 
Published: March 2012

Abstract
Immobilized DNA is required for the development of DNA chips and arrays, DNA sensors, or other sensing devices including microfluidics, in addition to gene delivery devices. The broad application range for all of these DNA‐based systems is to a major extent found in the medical area, using the devices also in DNA sequencing and furthermore for food and environmental analyses. Therefore, strategies for DNA immobilization are described in this article, with focus on immobilization chemistry. Depending on the different surfaces, various immobilization techniques (e.g. via physical adsorption, covalent, affinity binding, and matrix entrapment) were developed and optimized, which are described for carbonaceous materials (e.g. carbon nanotubes), silica and silicon surfaces, gold surfaces, the same as for more recently complex biocompatible surfaces (e.g. polymeric gels). The ‘top‐down techniques’ can be distinguished from the ‘bottom‐up’ techniques started in the very beginning of DNA chip development. More recently, surfaces such as stents or biocompatible transplants are on focus to generate therapeutic devices. In the future, the power of DNA as a self‐assembling material could be used to combine both the ‘bottom‐up’ and ‘top‐down’ strategies to generate complex nanostructures with multifunctional applications (e.g. three‐dimensional DNA ‘origami’). Overall, the main aim of this article is to provide an overview of the methods currently used for DNA immobilization regarding the broad variety of the above mentioned potential applications.
Stable Isotope Analysis: Hair and Nails
Authors: Meier‐Augenstein Wolfram , Kemp Helen F 
Published: March 2012

AbstractWhile bone and teeth provide a long‐term stable isotope record of a person's life history measured in years (seeStabel Isotope Analysis: Bone and Teeth), stable isotope profiles of hair and nail can yield information on a person's recent life circumstance up to 15 months into a person's past. Since hair and nail samples can be collected noninvasively, stable isotope profiles of these tissues may also be used to reveal information on recent geographic movement in living people. This information may prove useful to check on the veracity of a suspect's statement about their recent geographic movements.
Image Comparison: Facial, Photographic
Authors: Davis Josh P. 
Published: March 2012

AbstractPhotographic facial image comparison analysis refers to techniques designed to determine whether two or more photographic images depict the same person or not. One of the images will normally either be the suspect in a police investigation, or the defendant in court. Comparison crime scene evidence will often be images acquired from sources such as closed circuit television cameras (CCTV). There are three primary techniques used by expert witnesses to present opinion evidence of identity in court. With photoanthropometric analysis, the proportional distances and angles between specified facial features visible in photographs are measured and compared across evidence. With morphological comparison analysis, facial features are visually inspected and classified into predetermined categories. Finally, with photographic superimposition analysis, one photograph or video still is superimposed over a second, to perform a series of visual inspections. The forensic reliability of each method with two‐dimensional photographs is questionable, particularly, if the image quality is poor, or the facial viewpoints in different images do not match. Furthermore, expert opinion of identity evidence is rarely accompanied with statistical margins of error, or the probability that images depict two different individuals. Nevertheless, recent innovations using three‐dimensional image capture technology have suggested that in the future, there may be improvements in the reliability of photographic facial image comparison techniques.
Sleep and EEG Phenotyping in Mice
Authors: Mang Géraldine Morgane , Franken Paul 
Published: March 2012

AbstractAlthough alternative, noninvasive methods are being developed, current research on rodent sleep still almost exclusively relies on recording the electroencephalogram (EEG). EEG provides information about the electrical activity of the brain and is, in combination with the electromyogram (EMG), primarily used to distinguish the different sleep and wake states. This unit describes the technique used to record EEG and EMG signals in freely moving mice, under standard laboratory conditions or specific experimental protocols such as sleep deprivation (SD). In addition to its use to determine behavioral state, the EEG contains a wealth of information concerning rhythmic brain activity that can be extracted using signal analysis tools. We will describe the protocol for implantation of EEG and EMG electrodes, provide examples of experimental designs, and discuss data acquisition and analysis illustrating the type of information that can be obtained from the EEG in mice. Curr. Protoc. Mouse Biol. 2:54‐74 © 2012 by John Wiley & Sons, Inc.
Acoustic Startle Reflex and Prepulse Inhibition
Authors: Ouagazzal Abdel Mottalib , Meziane Hamid 
Published: March 2012

AbstractThe completion of genome sequencing in humans and mice has opened new opportunities to study the relationship between gene expression and behavior and for development of novel therapeutic approaches for brain diseases. Recently, several international programs for large‐scale production and phenotyping of genetically modified mice have been launched (e.g., EUCOMM, EUMODIC, IMPC), and comprehensive high‐throughput behavioral phenotyping strategies have been developed (EUMORPHIA). In this context, startle reflex represents an important research tool for studying the impact of genetic manipulations not only on sensory processes but also on complex brain functions such as cognition, emotions, and movement control. In this unit, step‐by‐step protocols for measurement of acoustic startle reactivity and prepulse inhibition of startle in mice are described, and supporting experimental data presented. Curr. Protoc. Mouse Biol. 2:25‐35 © 2012 by John Wiley & Sons, Inc.
Superhard Materials
Authors: Mohammadi Reza , Kaner Richard B. 
Published: March 2012

Abstract

Materials possessing superior hardness can be divided into two main categories: ultra‐hard and superhard. Diamond and cubic boron nitride (
c
‐BN) are considered ultra‐hard with hardness values ranging from 70 to 110 and 45 to 60 GPa, respectively. All other materials with a hardness of greater than 40 GPa are called superhard. Ultra‐hard materials are traditionally used in industrial applications including cutting tools and wear‐protecting surfaces. However, diamond is not a good choice for high‐speed cutting of ferrous‐based alloys because of its graphitization on the material's surface and formation of brittle carbides, which leads to poor cutting performance. In addition, the synthesis of both diamond and
c
‐BN requires high pressure‐high temperature conditions. Therefore, a great deal of effort has been made to address these shortcomings and to find a reliable substitute for these ultra‐hard materials. Studies have been directed toward the development of either main group compounds (such as SiC and Si
3
N
4
) or transition‐metal compounds (such as WC and HfN). Unfortunately, most of these compounds are not superhard (e.g., WC, SiC) or their synthesis needs high pressures and high temperatures (e.g., Si
3
N
4
) that entails expensive equipment and processing costs. Among these compounds, dense transition‐metal diborides have exhibited very promising mechanical properties including great hardness, while remaining relatively easy to synthesize at ambient pressure, and may form the next generation of cutting tools and abrasion‐resistant coatings. In this article, we will review the recent advancements in synthesis and characterization of single‐phase ultra‐hard and superhard materials, with a special focus on transition‐metal diborides. We hope that this article may shed light on the inconsistencies of some of the data reported in the literature and make comparisons among materials possessing great hardness easier. Except for some rare cases, the hardness of thin films and composites will not be covered here and left for a future study.
Time‐dependent increased risk for serious infection from continuous use of tumor necrosis factor antagonists over three years in patients with rheumatoid arthritis
Authors: Sakai Ryoko , Komano Yukiko , Tanaka Michi , Nanki Toshihiro , Koike Ryuji , Nagasawa Hayato , Amano Koichi , Nakajima Atsuo , Atsumi Tatsuya , Koike Takao , Ihata Atsushi , Ishigatsubo Yoshiaki , Saito Kazuyoshi , Tanaka Yoshiya , Ito Satoshi , Sumida Takayuki , Tohma Shigeto , Tamura Naoto , Fujii Takao , Sugihara Takahiko , Kawakami Atsushi , Hagino Noboru , Ueki Yukitaka , Hashiramoto Akira , Nagasaka Kenji , Miyasaka Nobuyuki , Harigai Masayoshi ,   for the Real Study Group
Published: March 2012

AbstractObjectiveTo investigate associations between continuous treatments with tumor necrosis factor (TNF) antagonists and risk for developing serious infections (SIs) over 3 years in Japanese patients with rheumatoid arthritis (RA) enrolled in the Registry of Japanese RA Patients for Long‐Term Safety (REAL) database.MethodsWe analyzed 727 RA patients who had started either infliximab or etanercept (the anti‐TNF group; 1,480.1 patient‐years [PY]) and 571 RA patients who had started conventional nonbiologic disease‐modifying antirheumatic drugs (the unexposed group; 1,104.1 PY) at the time of enrollment in the REAL. We assessed the occurrence of SIs within a 3‐year observation period, including the period after switching to other TNF antagonists, and all SIs, unlimited to the first one in each patient as reported in other studies, to evaluate the real safety of TNF antagonists in daily practice.ResultsThe incidence rate of SIs per 100 PY was 5.54 (95% confidence interval [95% CI] 4.44–6.84) in the anti‐TNF group and 2.72 (95% CI 1.87–3.83) in the unexposed group. Poisson regression analysis revealed that the relative risk (RR) of continuous use of TNF antagonists for SIs after adjusting for baseline and time‐dependent covariates was significantly elevated both overall (1.97, 95% CI 1.25–3.19) and for the first year (2.40, 95% CI 1.20–5.03), but not for the second and third years combined (1.38, 95% CI 0.80–2.43). The adjusted RR for SIs of etanercept compared to infliximab was not significantly elevated.ConclusionContinuous anti‐TNF therapy was significantly associated with increased risks for developing SIs during, but not after, the first year.
Sources of Hysteresis in Carbon Nanotube Field‐Effect Transistors and Their Elimination Via Methylsiloxane Encapsulants and Optimized Growth Procedures
Authors: Jin Sung Hun , Islam Ahmad E. , Kim Tae‐il , Kim Ji‐hun , Alam Muhammad A. , Rogers John A. 
Published: March 2012

AbstractThe origins of gate‐induced hysteresis in carbon nanotube field‐effect transistors are explained and techniques to eliminate this hysteresis with encapsulating layers of methylsiloxane and modified processes for nanotube growth are reported. A combined experimental and theoretical analysis of the dependence of hysteresis on the gate voltage sweep‐rate reveals the locations, types, and densities of defects that contribute to hysteresis. Devices with designs that eliminate these defects exhibit more than ten times reduction in hysteresis compared to conventional layouts. Demonstrations in individual transistors that use both networks and arrays of nanotubes, and in simple logic gates built with these devices, illustrate the utility of the proposed approaches.