bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving autonomy and control of autonomous surface vehicles in port protection and mine countermeasure scenarios
Authors: Pastore Thomas , Djapic Vladimir 
Published: August 2010

AbstractRecent experimentation with autonomous surface vehicles (ASVs) has focused on the use of such platforms to perform tasks of classification or identification of objects first discovered by another sensor. The ASV generally carries small sensors capable of high‐resolution imaging, but only at relatively short ranges. Reacquisition of a contact is inherent in the problem of classification and involves positioning of the surface vehicle with good precision such that the object of interest is in the field of view of the sensors aboard the ASV. This critical task of positioning the vehicle such that the classification sensors can be effectively brought to bear is the primary goal of our autonomy development. Experimental results from a variety of sensors are presented, but the most important in our present work has been a high‐resolution multibeam imaging sonar operating at 450 kHz. This sensor has been successfully used to image divers and bottom objects, with telemetry data sent back to shore via wireless LAN. Although classification was done by a human operator ashore, the vehicle has the capability to keep an object in view of the sensor, representing an important operational advantage of the autonomy. Future work could expand the role of the unmanned platform to deployment of effectors—warning devices or entanglement devices in the case of harbor protection missions or neutralization devices in the case of countermine operations. © 2010 Wiley Periodicals, Inc.
Airborne vision‐based collision‐detection system
Authors: Lai John , Mejias Luis , Ford Jason J. 
Published: August 2010

AbstractMachine vision represents a particularly attractive solution for sensing and detecting potential collision‐course targets due to the relatively low cost, size, weight, and power requirements of vision sensors (as opposed to radar and Traffic Alert and Collision Avoidance System). This paper describes the development and evaluation of a real‐time, vision‐based collision‐detection system suitable for fixed‐wing aerial robotics. Using two fixed‐wing unmanned aerial vehicles (UAVs) to recreate various collision‐course scenarios, we were able to capture highly realistic vision (from an onboard camera perspective) of the moments leading up to a collision. This type of image data is extremely scarce and was invaluable in evaluating the detection performance of two candidate target detection approaches. Based on the collected data, our detection approaches were able to detect targets at distances ranging from 400 to about 900 m. These distances (with some assumptions about closing speeds and aircraft trajectories) translate to an advance warning of between 8 and 10 s ahead of impact, which approaches the 12.5‐s response time recommended for human pilots. We overcame the challenge of achieving real‐time computational speeds by exploiting the parallel processing architectures of graphics processing units (GPUs) found on commercial‐off‐the‐shelf graphics devices. Our chosen GPU device suitable for integration onto UAV platforms can be expected to handle real‐time processing of 1,024 × 768 pixel image frames at a rate of approximately 30 Hz. Flight trials using manned Cessna aircraft in which all processing is performed onboard will be conducted in the near future, followed by further experiments with fully autonomous UAV platforms. © 2010 Wiley Periodicals, Inc.
Nonparametric sequential monitoring of longitudinal trials
Authors: Bogowicz P. , Gombay E. , Heo G. 
Published: August 2010

AbstractThis paper considers the sequential monitoring of multi‐armed longitudinal clinical trials. We describe an approach that is relatively simple and accessible. Sequential ranks are used to form partial sum statistics, yielding processes that have independent increments, and hence can be approximated by Brownian motions. Three monitoring procedures are proposed. The first two are asymptotic, continuous analogues of the well‐known Pocock and O'Brien–Fleming group sequential procedures, whereas the third procedure is exact. Performance of the procedures is assessed using Monte Carlo simulations. Data from an orthodontic clinical trial is used to illustrate the proposed methods, for the comparison of three treatment groups. Copyright © 2010 John Wiley & Sons, Ltd.
What can go wrong when ignoring correlation bounds in the use of generalized estimating equations
Authors: Sabo R. T. , Chaganty N. R. 
Published: August 2010

AbstractThe analysis of repeated measure or clustered data is often complicated by the presence of correlation. Further complications arise for discrete responses, where the marginal probability‐dependent Fr'echet bounds impose feasibility limits on the correlation that are often more restrictive than the positive definite range. Some popular statistical methods, such as generalized estimating equations (GEE), ignore these bounds, and as such can generate erroneous estimates and lead to incorrect inferential results. In this paper, we discuss two alternative strategies: (i) using QIC to select a data‐driven correlation value within the Fréchet bounds, and (ii) the use of likelihood‐based latent variable modeling, such as multivariate probit, to get around the problem all together. We provide two examples of the repercussions of incorrectly using existing GEE software in the presence of correlated binary responses. Copyright © 2010 John Wiley & Sons, Ltd.
Propinquity in global software engineering: examining perceived distance in globally distributed project teams
Authors: Prikladnicki Rafael 
Published: August 2010

SUMMARYIn social psychology, propinquity refers to the physical (objective) or psychological (subjective) proximity between people. In this paper, we explore the psychological dimension of propinquity by examining the phenomenon of feeling distant from geographically distributed people, in the context of distributed software teams. The perceived distance is an important challenge faced by distributed teams, and it is frequently based on factors beyond the physical distance, such as communication and cultural differences. The purpose of this paper is to present a model to assess and make more visible the construct of ‘perceived distance’ among members of global software engineering teams. The model was applied in three real‐world cases to assess its effectiveness in uncovering hidden and useful information during the project lifecycle. The practical experience lived with the quantification of perceived distance gave us good indication that this data can benefit the practice of global software engineering. In most of the projects evaluated, project managers were not expecting the results found. We present the model, details of its applications, analysis of the results, lessons learned and practical implications for the management of distributed software projects and teams. Copyright © 2010 John Wiley & Sons, Ltd.
Methodology for process improvement through basic components and focusing on the resistance to change
Authors: Calvo‐Manzano Jose A. , Cuevas Gonzalo , Gómez Gerzón , Mejia Jezreel , Muñoz Mirna , San Feliu Tomás 
Published: August 2010

SUMMARYThis paper describes a multi‐model methodology that implements a smooth and continuous process improvement, depending on the organization's business goals and allowing users to establish their improvement implementation pace. The methodology focuses on basic process components known as ‘best practices’. Besides, it covers following the topics: knowledge management and change management. The methodology description and the results of a case study on project management process are included. Copyright © 2010 John Wiley & Sons, Ltd.
Performance analysis and comparison of burst transmission schemes in unsaturated 802.11e WLANs
Authors: Hu Jia , Min Geyong , Woodward Mike E. 
Published: August 2010

AbstractContention free bursting (CFB) and block acknowledgement (BACK) are two innovative burst transmission schemes specified in the IEEE 802.11e standard for reducing the contention overheads and further improving the channel utilization of wireless local area networks (WLANs). Existing studies on performance analysis of the CFB and BACK schemes have been primarily focused on the system throughput and have not taken into account the realistic factors, such as unsaturated traffic loads and finite buffer capacity. To fill this gap, this paper proposes a new and comprehensive analytical model for evaluating the Quality‐of‐Service (QoS) metrics including throughput, end‐to‐end delay, and frame loss probability of both burst transmission schemes under unsaturated traffic conditions. The proposed model is validated through extensive simulation experiments and then is used to conduct performance analysis and comparison of the burst transmission schemes under various working conditions. The analytical results reveal that (1) both CFB and BACK schemes can substantially improve the QoS performance; (2) BACK scheme outperforms the CFB scheme when the transmission opportunity (TXOP) limit exceeds a threshold; (3) the analytical model can be used to identify the optimal configuration of system parameters for the burst transmission schemes subject to QoS constraints. Copyright © 2010 John Wiley & Sons, Ltd.
Provenance of freshwater pulses in the Gulf of Mexico during the last deglaciation
Authors: Sionneau T. , Bout-Roumazeilles V. , Flower B.P. , Bory A. , Tribovillard N. , Kissel C. , Van Vliet-Lanoë B. , Montero Serrano J.C. 
Published: August 2010

AbstractDuring the last deglaciation, the decaying Laurentide Ice Sheet (LIS) delivered huge volumes of meltwater toward the Gulf of Mexico. The present investigation of clay mineralogy and grain-size characteristics of terrigenous sediments deposited in the Orca Basin (Gulf of Mexico) offers a unique opportunity to link the marine record of these meltwater floods with the reconstructed continental glacial history and the modeled drainage patterns. Five peculiar sedimentary levels, characterized by high smectite content and low CaCO3 content, were identified and occurred simultaneously with major meltwater floods. According to recently published clay mineral distribution maps for North America, these results help to pinpoint the southwestern margin of the LIS as a main contributor to most of the meltwater discharges. In addition, the peculiar mineralogical composition (illite and chlorite-rich) of the sediments characterizing the meltwater episode associated with Heinrich event 1 suggests a provenance from the Great Lakes area, supporting the interpretation of destabilization of the LIS southeastern margin during this event. Decreased terrigenous contribution associated with changing provenance of sediments after 12.9 cal ka BP suggests strong modifications of the continental hydrography in relation to Lake Agassiz history and changes in the morphology of Mississippi delta due to rising sea level.
The Most Redundant Sequences in Human CpG Island Library Are Derived from Mitochondrial Genome
Authors: He Ximiao , Tao Shu , Jin Jing , Hu Songnian , Yu Jun 
Published: August 2010

Abstract
An altered pattern of epigenetic modifications, such as DNA methylation and histone modification, is critical to many common human diseases, including cancer. Recently, mitochondrial DNA (mtDNA) was reported to be associated with tumorigenesis through epigenetic regulation of methylation patterns. One of the promising approaches to study DNA methylation and CpG islands (CGIs) is sequencing and analysis of clones derived from the physical library generated by methyl-CpG-binding domain proteins and restriction enzyme MseI. In this study, we observed that the most redundant sequences of 349 clones in a human CGI library were all generated from the human mitochondrial genome. Further analysis indicated that there was a 5,845-bp DNA transfer from mtDNA to chromosome 1, and all the clones should be the products of a 510-bp MseI fragment, which contained a putative CGI of 270 bp. The 510-bp fragment was annotated as part of cytochrome c oxidase subunit II (COXII), and phylogenetic analysis of homologous sequences containing COXII showed three DNA transfer events from mtDNA to nuclear genome, one of which underwent secondary transfer events between different chromosomes. These results may further our understanding of how the mtDNA regulates DNA methylation in the nucleus.
Sequence Signatures of Nucleosome Positioning in Caenorhabditis Elegans
Authors: Chen Kaifu , Wang Lei , Yang Meng , Liu Jiucheng , Xin Chengqi , Hu Songnian , Yu Jun 
Published: August 2010

Abstract
Our recent investigation in the protist Trichomonas vaginalis suggested a DNA sequence periodicity with a unit length of 120.9 nt, which represents a sequence signature for nucleosome positioning. We now extended our observation in higher eukaryotes and identified a similar periodicity of 175 nt in length in Caenorhabditis elegans. In the process of defining the sequence compositional characteristics, we found that the 10.5-nt periodicity, the sequence signature of DNA double helix, may not be sufficient for cross-nucleosome positioning but provides essential guiding rails to facilitate positioning. We further dissected nucleosome-protected sequences and identified a strong positive purine (AG) gradient from the 5′-end to the 3′-end, and also learnt that the nucleosome-enriched regions are GC-rich as compared to the nucleosome-free sequences as purine content is positively correlated with GC content. Sequence characterization allowed us to develop a hidden Markov model (HMM) algorithm for decoding nucleosome positioning computationally, and based on a set of training data from the fifth chromosome of C. elegans, our algorithm predicted 60%-70% of the well-positioned nucleosomes, which is 15%-20% higher than random positioning. We concluded that nucleosomes are not randomly positioned on DNA sequences and yet bind to different genome regions with variable stability, well-positioned nucleosomes leave sequence signatures on DNA, and statistical positioning of nucleosomes across genome can be decoded computationally based on these sequence signatures.
Genome-Wide Survey and Evolutionary Analysis of Trypsin Proteases in Apicomplexan Parasites
Authors: Arenas Aylan Farid , Osorio-Méndez Juan Felipe , Gutierrez Andres Julian , Gomez-Marin Jorge E. 
Published: August 2010

Abstract
Apicomplexa are an extremely diverse group of unicellular organisms that infect humans and other animals. Despite the great advances in combating infectious diseases over the past century, these parasites still have a tremendous social and economic burden on human societies, particularly in tropical and subtropical regions of the world. Proteases from apicomplexa have been characterized at the molecular and cellular levels, and central roles have been proposed for proteases in diverse processes. In this work, 16 new genes encoding for trypsin proteases are identified in 8 apicomplexan genomes by a genome-wide survey. Phylogenetic analysis suggests that these genes were gained through both intracellular gene transfer and vertical gene transfer. Identification, characterization and understanding of the evolutionary origin of protease-mediated processes are crucial to increase the knowledge and improve the strategies for the development of novel chemotherapeutic agents and vaccines.
BiDiBlast: Comparative Genomics Pipeline for the PC
Authors: de Almeida João M.G.C.F. 
Published: August 2010

Abstract
Bi-directional BLAST is a simple approach to detect, annotate, and analyze candidate orthologous or paralogous sequences in a single go. This procedure is usually confined to the realm of customized Perl scripts, usually tuned for UNIX-like environments. Porting those scripts to other operating systems involves refactoring them, and also the installation of the Perl programming environment with the required libraries. To overcome these limitations, a data pipeline was implemented in Java. This application submits two batches of sequences to local versions of the NCBI BLAST tool, manages result lists, and refines both bi-directional and simple hits. GO Slim terms are attached to hits, several statistics are derived, and molecular evolution rates are estimated through PAML. The results are written to a set of delimited text tables intended for further analysis. The provided graphic user interface allows a friendly interaction with this application, which is documented and available to download at http://moodle.fct.unl.pt/course/view.php?id=2079 or https://sourceforge.net/projects/bidiblast/ under the GNU GPL license.
Transitivity in spaces of vector-valued functions
Authors: Sánchez Félix Cabello 
Published: August 2010

AbstractWe exhibit a real Banach space M such that C(K,M) is almost transitive if K is the Cantor set, the growth of the integers in its Stone–Čech compactification or the maximal ideal space of L∞. For finite K, the space C(K,M) = M|K| is even transitive.
Characterizing Jordan maps on C*-algebras through zero products
Authors: Alaminos J. , Brešar J. M. , Extremera J. , Villena A. R. 
Published: August 2010

AbstractLet A and B be C*-algebras, let X be an essential Banach A-bimodule and let T : A → B and S : A → X be continuous linear maps with T surjective. Suppose that T(a)T(b) + T(b)T(a) = 0 and S(a)b + bS(a) + aS(b) + S(b)a = 0 whenever a, b ε A are such that ab = ba = 0. We prove that then T = wΦ and S = D + Ψ, where w lies in the centre of the multiplier algebra of B, Φ: A → B is a Jordan epimorphism, D: A → X is a derivation and Ψ: A → X is a bimodule homomorphism.
Schmidt’s game, fractals, and orbits of toral endomorphisms
Authors: BRODERICK RYAN , FISHMAN LIOR , KLEINBOCK DMITRY 
Published: August 2010

AbstractGiven an integer matrix M∈GLn(ℝ) and a point y∈ℝn/ℤn, consider the set S. G. Dani showed in 1988 that whenever M is semisimple and y∈ℚn/ℤn, the set $ \tilde E(M,y)$ has full Hausdorff dimension. In this paper we strengthen this result, extending it to arbitrary M∈GLn(ℝ)∩Mn×n(ℤ) and y∈ℝn/ℤn, and in fact replacing the sequence of powers of M by any lacunary sequence of (not necessarily integer) m×n matrices. Furthermore, we show that sets of the form $ \tilde E(M,y)$ and their generalizations always intersect with ‘sufficiently regular’ fractal subsets of ℝn. As an application, we give an alternative proof of a recent result [M. Einsiedler and J. Tseng. Badly approximable systems of affine forms, fractals, and Schmidt games. Preprint, arXiv:0912.2445] on badly approximable systems of affine forms.
On the Suitability of SIFT Technique to Deal with Image Modifications Specific to Confocal Scanning Laser Microscopy
Authors: Stanciu Stefan G. , Hristu Radu , Boriga Radu , Stanciu George A. 
Published: August 2010

AbstractComputer vision tasks such as recognition and classification of objects and structures or image registration and retrieval can provide significant information when applied to microscopy images. Recently developed techniques for the detection and description of local features make the extraction and description of local image features that are invariant to various changes possible. The invariance and robustness of feature detection and description techniques play a key role in the design and implementation of object recognition, image registration, or image mosaicing applications. The scale-invariant feature transform (SIFT) technique is a widely used method for the detection, description, and matching of image features. In this article we present the results of our experiments regarding the repeatability of SIFT features, and to the precision of the SIFT feature matching, under image modifications specific to confocal scanning laser microscopy (CSLM). We have analyzed the behavior of SIFT while changing the pinhole aperture, photomultiplier gain, laser beam power, and electronic zoom. Our experiments, conducted on CSLM images, show that the SIFT technique is able to match detected key points between images acquired at different values of the acquisition parameters with good precision and represents a consistent tool for computer vision applications in CSLM.
Dominant and diet-responsive groups of bacteria within the human colonic microbiota
Authors: Walker Alan W , Ince Jennifer , Duncan Sylvia H , Webster Lucy M , Holtrop Grietje , Ze Xiaolei , Brown David , Stares Mark D , Scott Paul , Bergerat Aurore , Louis Petra , McIntosh Freda , Johnstone Alexandra M , Lobley Gerald E , Parkhill Julian , Flint Harry J 
Published: August 2010

Abstract
The populations of dominant species within the human colonic microbiota can potentially be modified by dietary intake with consequences for health. Here we examined the influence of precisely controlled diets in 14 overweight men. Volunteers were provided successively with a control diet, diets high in resistant starch (RS) or non-starch polysaccharides (NSPs) and a reduced carbohydrate weight loss (WL) diet, over 10 weeks. Analysis of 16S rRNA sequences in stool samples of six volunteers detected 320 phylotypes (defined at &gt;98% identity) of which 26, including 19 cultured species, each accounted for &gt;1% of sequences. Although samples clustered more strongly by individual than by diet, time courses obtained by targeted qPCR revealed that ‘blooms’ in specific bacterial groups occurred rapidly after a dietary change. These were rapidly reversed by the subsequent diet. Relatives of Ruminococcus bromii (R-ruminococci) increased in most volunteers on the RS diet, accounting for a mean of 17% of total bacteria compared with 3.8% on the NSP diet, whereas the uncultured Oscillibacter group increased on the RS and WL diets. Relatives of Eubacterium rectale increased on RS (to mean 10.1%) but decreased, along with Collinsella aerofaciens, on WL. Inter-individual variation was marked, however, with &gt;60% of RS remaining unfermented in two volunteers on the RS diet, compared to &lt;4% in the other 12 volunteers; these two individuals also showed low numbers of R-ruminococci (&lt;1%). Dietary non-digestible carbohydrate can produce marked changes in the gut microbiota, but these depend on the initial composition of an individual's gut microbiota.
Multiple syntrophic interactions in a terephthalate-degrading methanogenic consortium
Authors: Lykidis Athanasios , Chen Chia-Lung , Tringe Susannah G , McHardy Alice C , Copeland Alex , Kyrpides Nikos C , Hugenholtz Philip , Macarie Hervé , Olmos Alejandro , Monroy Oscar , Liu Wen-Tso 
Published: August 2010

Abstract
Terephthalate (TA) is one of the top 50 chemicals produced worldwide. Its production results in a TA-containing wastewater that is treated by anaerobic processes through a poorly understood methanogenic syntrophy. Using metagenomics, we characterized the methanogenic consortium inside a hyper-mesophilic (that is, between mesophilic and thermophilic), TA-degrading bioreactor. We identified genes belonging to dominant Pelotomaculum species presumably involved in TA degradation through decarboxylation, dearomatization, and modified β-oxidation to H2/CO2 and acetate. These intermediates are converted to CH4/CO2 by three novel hyper-mesophilic methanogens. Additional secondary syntrophic interactions were predicted in Thermotogae, Syntrophus and candidate phyla OP5 and WWE1 populations. The OP5 encodes genes capable of anaerobic autotrophic butyrate production and Thermotogae, Syntrophus and WWE1 have the genetic potential to oxidize butyrate to CO2/H2 and acetate. These observations suggest that the TA-degrading consortium consists of additional syntrophic interactions beyond the standard H2-producing syntroph–methanogen partnership that may serve to improve community stability.