An approach to vision-based station keeping for an unmanned underwater vehicle

This paper presents an automatic vision-based system for UUV station keeping. The vehicle is equipped with a down-looking camera, which provides images of the sea-floor. The station keeping system is based on a feature-based motion detection algorithm, which exploits standard correlation and explicit textural analysis to solve the correspondence problem. A visual map of the area surveyed by the vehicle is constructed to increase the flexibility of the system, allowing the vehicle to position itself when it has lost the reference image. The testing platform is the URIS underwater vehicle. Experimental results demonstrating the behavior of the system on a real environment are presented

A system to evaluate the accuracy of a visual mosaicking methodology

When underwater vehicles navigate close to the ocean floor, computer vision techniques can be applied to obtain motion estimates. A complete system to create visual mosaics of the seabed is described in this paper. Unfortunately, the accuracy of the constructed mosaic is difficult to evaluate. The use of a laboratory setup to obtain an accurate error measurement is proposed. The system consists on a robot arm carrying a downward looking camera. A pattern formed by a white background and a matrix of black dots uniformly distributed along the surveyed scene is used to find the exact image registration parameters. When the robot executes a trajectory (simulating the motion of a submersible), an image sequence is acquired by the camera. The estimated motion computed from the encoders of the robot is refined by detecting, to subpixel accuracy, the black dots of the image sequence, and computing the 2D projective transform which relates two consecutive images. The pattern is then substituted by a poster of the sea floor and the trajectory is executed again, acquiring the image sequence used to test the accuracy of the mosaicking system

Moderating effects of management control systems and innovation on performance. Simple methods for correcting the effects of measurement error for interaction effects in small samples

In the accounting literature, interaction or moderating effects are usually assessed by means of OLS regression and summated rating scales are constructed to reduce measurement error bias. Structural equation models and two-stage least squares regression could be used to completely eliminate this bias, but large samples are needed. Partial Least Squares are appropriate for small samples but do not correct measurement error bias. In this article, disattenuated regression is discussed as a small sample alternative and is illustrated on data of Bisbe and Otley (in press) that examine the interaction effect of innovation and style of use of budgets on performance. Sizeable differences emerge between OLS and disattenuated regression

Navegant entre narracions: recuperant silencis i subjectivitats. Recursos psicosocials en l’atenció a víctimes de violència de gènere en l’àmbit penal (jutjats i cos policial)

El treball pretén aportar un coneixement de caràcter psicosocial sobre els contextos on els professionals del sistema jurídic-penal ofereixen atenció a les víctimes de violència de gènere, concretament, les unitats i oficines habilitades per recollir la denúncia o atestat dins de les comissaries dels Mossos d’esquadra i els jutjats d´instrucció de la dona. L´àmbit territorial va ser Barcelona i Girona. Es va obtenir informació sobre judicis realitzats a l´Audiència provincial, així com documents legals en relació al tema. S’ha analitzat les necessitats i dificultats juntament amb la identificació dels recursos psicosocials que aporten tant aquests professionals com les dones que han patit o estan patit un procés de maltractament per part de la parella. La pretensió es oferir una mirada particular per suggerir transformacions que facilitin el procés d´atenció en aquests contextos, sovint difícil i, que comporta conseqüències emocionals per part de les víctimes i dels mateixos agents que les atenen. S’ha partit de les narracions de les víctimes i dels agents jurídics, com pràctiques socials a partir de les quals podem detectar valors, posicions, normes, emocions i efectes de gènere que permetrà dirigir la intervenció. Com a eines d´anàlisi s’ha fet ús els repertoris interpretatius els quals han permès analitzar les construccions socials i els seus efectes al voltant del maltracte, de les identitats de les víctimes i els victimaris.

Determinants of Spanish firms' life cycle and job

This paper examines the role of human capital, individual entrepreneurial traits and the business environment on firms' life cycle and on job creation in Spain. For this purpose, we have constructed a pseudo-panel, by using the Global Entrepreneurship Monitor survey over the period 2001-2008. We have found that the creation, maturity and survival of firms were aided by the availability of bank credit and the large immigration inflows that Spain received over this period. However, of these two factors, only bank credit had a positive effect on the creation of jobs and on improving expectations of job expansion. The relatively high levels of youth unemployment experienced even before the crises of 2008 hurt the firm's chances of maturity and survival. The results also suggested that the gender gap in entrepreneurial activities had narrowed. In relative terms, women with higher levels of education were more likely to create mature firms than men. Based on the empirical findings and those of related literature, the paper offers policy recommendations to foster a sustainable entrepreneurial sector capable of contributing to the recovery of the Spanish economy.

Positioning an underwater vehicle through image mosaicking

Mosaics have been commonly used as visual maps for undersea exploration and navigation. The position and orientation of an underwater vehicle can be calculated by integrating the apparent motion of the images which form the mosaic. A feature-based mosaicking method is proposed in this paper. The creation of the mosaic is accomplished in four stages: feature selection and matching, detection of points describing the dominant motion, homography computation and mosaic construction. In this work we demonstrate that the use of color and textures as discriminative properties of the image can improve, to a large extent, the accuracy of the constructed mosaic. The system is able to provide 3D metric information concerning the vehicle motion using the knowledge of the intrinsic parameters of the camera while integrating the measurements of an ultrasonic sensor. The experimental results of real images have been tested on the GARBI underwater vehicle

Incidència de l’entorn educatiu, familiar i social en les actituds lingüístiques i identitàries dels joves d’origen xinès i llatinoamericà a Catalunya

From an interdisciplinary perspective, the present investigation undertaken by the GREILI-UPF research group has expanded a previous study aiming at explaining how young secondary school students of Latin American and Chinese origin in Catalonia construct their linguistic and cultural identity. Here we analyze the relationship between these youngsters and their social environment in order to determine how these relationships and the socialization process that derives from them influence language attitudes and practices. We focus on two spaces of socialization: (1) the school, where youngsters from diverse cultural and linguistic backgrounds coexist and interact, and (2) the neighborhood, a geographic and symbolic space where social identity is constructed and, consequently, where young newcomers construct their perceptions regarding the host society, including its linguistic reality. We have collected several sets of data in three public secondary schools and three neighborhoods from Barcelona’s metropolitan area with a high index of immigrant population: (1) interviews with secondary school students, (2) interviews with teachers, (3) social discourses in newspapers that consolidate the social image of the neighborhood, (4) narratives from immigrant families in relation to their neighborhood, (5) participant observation in schools, and (5) observation in the neighborhood. The results of the thematic and, when appropriate, discursive analysis of the data allow us to reach conclusions regarding: (a) the social image of the neighborhoods, (b) the socialization of young newcomers in the schools and the neighborhoods, (c) the identity games, and (d) the language and cultural practices and attitudes of young people, in relation to their countries and languages of origin as well as the school and the neighborhood investigated.

A new all-round density functional based on spin states and SN2 barriers

We report here a new empirical density functional that is constructed based on the performance of OPBE and PBE for spin states and SN 2 reaction barriers and how these are affected by different regions of the reduced gradient expansion. In a previous study [Swart, Sol̀, and Bickelhaupt, J. Comput. Methods Sci. Eng. 9, 69 (2009)] we already reported how, by switching between OPBE and PBE, one could obtain both the good performance of OPBE for spin states and reaction barriers and that of PBE for weak interactions within one and the same (SSB-sw) functional. Here we fine tuned this functional and include a portion of the KT functional and Grimme's dispersion correction to account for π- π stacking. Our new SSB-D functional is found to be a clear improvement and functions very well for biological applications (hydrogen bonding, π -π stacking, spin-state splittings, accuracy of geometries, reaction barriers)

Gènere i identitats en la construcció d'una comunitat colonial a Empúries (segles VI-V a.C.)

El projecte de recerca ha analitzat la complexitat ètnica, social i de gènere de l’assentament colonial d’Empúries a partir d’un exhaustiu estudi contextual dels materials ceràmics d’ús quotidià provinents de diferents sectors excavats als anys vuitanta a la Neàpolis empuritana (N-7000, N-5000 i N-1000). Aquests sectors datats els segles V i IV a.C., corresponen a un moment en el qual s’està construint una identitat colonial diferenciada en l’espai emporità. La comparació dels aixovars domèstics usats quotidianament pels habitants d’aquest tres sectors situats en punts distants de la Neàpolis mostra que estem davant d’un assentament colonial molt heterogeni, on conflueixen materialitats, tradicions tecnològiques i pràctiques quotidianes iberes, gregues i híbrides. Els estudis de materials confirmen que no va existir una segregació espacial entre poblacions d’origen grec i iber en aquest assentament i suggereixen la cohabitació de gent –tant d’homes com de dones- d’origen grec i iber a les diferents àrees estudiades d’aquest assentament portuari. En el registre material ceràmic de totes les zones estudiades s’observa un predomini dels productes ceràmics de tradició grega (colonials o àtics) en els serveis de taula, però no així en els estris utilitzats a la cuina, que són majoritàriament de tradició ibera. També els materials ceràmics relacionats amb l’emmagatzematge domèstic i amb el transport i el comerç (àmfores) són predominantment ibers. Aquest patró suggereix que els ibers que van cohabitar amb els grecs al port emporità no van assumir en tots els casos posicions subalternes, sinó que tingueren un rol rellevant en la gestió econòmica i comercial d’aquest espai portuari.

CO2 emissions embodied in international trade: A multiregional Inputoutput model for Spain

As a result of globalization and free trade agreements, international trade is enormously growing and inevitably putting more pressure on the environment over the last few decades. This has drawn the attention of both environmentalist and economist in response to the ever growing concerns of climate change and urgent need of international action for its mitigation. In this work we aim at analyzing the implication of international trade in terms of CO2 between Spain and its important partners using a multi-regional input-output (MRIO) model. A fully integrated 13 regions MRIO model is constructed to examine the pollution responsibility of Spain both from production and consumption perspectives. The empirical results show that Spain is a net importer of CO2 emissions which is equivalent to 29% of its emission due to production. Even though the leading partner with regard to import values are countries such as Germany, France, Italy and Great Britain, the CO2 embodied due to trade with China takes the largest share. This is mainly due to the importation of energy intensive products from China coupled with Chinese poor energy mix which is dominated by coal-power plant. The largest portion (67%) of the global imported CO2 emissions is due to intermediate demand requirements by production sectors. Products such as Motor vehicles, chemicals, a variety of machineries and equipments, textile and leather products, construction materials are the key imports that drive the emissions due to their production in the respective exporting countries. Being at its peak in 2005, the Construction sector is the most responsible activity behind both domestic and imported emissions.

Estudi de la regulació del procés de formació de la fusta per a l’obtenció de biomassa i biocombustibles: el paper clau de dos factors de transcripció MYB amb funcions antagòniques

Estudi realitzat a partir d’una estada al Laboratoire de Recherche en Sciences Végétales - Université Toulouse III, entre 2010 i 2012. Durant l’estada s’han pogut complir els principals objectius del projecte de recerca sobre la regulació de la formació de les parets secundàries en un arbre d’importància econòmica, l’eucaliptus. S’ha caracteritzat dos factors de transcripció, EgMYB1 i 2, comparant el seu patró d’expressió espaciotemporal a nivell cel•lular i estudiant l’efecte fenotípic de la pèrdua de funció d’aquests gens. A més, s’ha construït una llibreria de xilema d’eucaliptus adaptada a la tècnica dels dos híbrids i s’ha descobert alguns del partners proteics d’EgMYB1 i 2, els quals estic actualment validant per mètodes alternatius. Augmentant els objectius inicials de la sol•licitud, he aprofitat la recent publicació del genoma de l’Eucalyptus grandis per identificar i caracteritzar el patró d’expressió de vàries famílies gèniques.

An assessment of gene prediction accuracy in large DNA sequences

One of the first useful products from the human genome will be a set of predicted genes. Besides its intrinsic scientific interest, the accuracy and completeness of this data set is of considerable importance for human health and medicine. Though progress has been made on computational gene identification in terms of both methods and accuracy evaluation measures, most of the sequence sets in which the programs are tested are short genomic sequences, and there is concern that these accuracy measures may not extrapolate well to larger, more challenging data sets. Given the absence of experimentally verified large genomic data sets, we constructed a semiartificial test set comprising a number of short single-gene genomic sequences with randomly generated intergenic regions. This test set, which should still present an easier problem than real human genomic sequence, mimics the approximately 200kb long BACs being sequenced. In our experiments with these longer genomic sequences, the accuracy of GENSCAN, one of the most accurate ab initio gene prediction programs, dropped significantly, although its sensitivity remained high. Conversely, the accuracy of similarity-based programs, such as GENEWISE, PROCRUSTES, and BLASTX was not affected significantly by the presence of random intergenic sequence, but depended on the strength of the similarity to the protein homolog. As expected, the accuracy dropped if the models were built using more distant homologs, and we were able to quantitatively estimate this decline. However, the specificities of these techniques are still rather good even when the similarity is weak, which is a desirable characteristic for driving expensive follow-up experiments. Our experiments suggest that though gene prediction will improve with every new protein that is discovered and through improvements in the current set of tools, we still have a long way to go before we can decipher the precise exonic structure of every gene in the human genome using purely computational methodology.

X-chromosome tiling path array detection of copy number variants in patients with chromosome X-linked mental retardation

Background: Aproximately 5–10% of cases of mental retardation in males are due to copy number variations (CNV) on the X chromosome. Novel technologies, such as array comparative genomic hybridization (aCGH), may help to uncover cryptic rearrangements in X-linked mental retardation (XLMR) patients. We have constructed an X-chromosome tiling path array using bacterial artificial chromosomes (BACs) and validated it using samples with cytogenetically defined copy number changes. We have studied 54 patients with idiopathic mental retardation and 20 controls subjects. Results: Known genomic aberrations were reliably detected on the array and eight novel submicroscopic imbalances, likely causative for the mental retardation (MR) phenotype, were detected. Putatively pathogenic rearrangements included three deletions and five duplications (ranging between 82 kb to one Mb), all but two affecting genes previously known to be responsible for XLMR. Additionally, we describe different CNV regions with significant different frequencies in XLMR and control subjects (44% vs. 20%). Conclusion:This tiling path array of the human X chromosome has proven successful for the detection and characterization of known rearrangements and novel CNVs in XLMR patients.

Cross recurrence quantification for cover song identification

There is growing evidence that nonlinear time series analysis techniques can be used to successfully characterize, classify, or process signals derived from realworld dynamics even though these are not necessarily deterministic and stationary. In the present study we proceed in this direction by addressing an important problem our modern society is facing, the automatic classification of digital information. In particular, we address the automatic identification of cover songs, i.e. alternative renditions of a previously recorded musical piece. For this purpose we here propose a recurrence quantification analysis measure that allows tracking potentially curved and disrupted traces in cross recurrence plots. We apply this measure to cross recurrence plots constructed from the state space representation of musical descriptor time series extracted from the raw audio signal. We show that our method identifies cover songs with a higher accuracy as compared to previously published techniques. Beyond the particular application proposed here, we discuss how our approach can be useful for the characterization of a variety of signals from different scientific disciplines. We study coupled Rössler dynamics with stochastically modulated mean frequencies as one concrete example to illustrate this point.

Patient-specific computational hemodynamics of intracranial aneurysms from 3D rotational angiography and CT angiography: an in vivo reproducibility study

Patient-specific simulations of the hemodynamics in intracranial aneurysms can be constructed by using image-based vascular models and CFD techniques. This work evaluates the impact of the choice of imaging technique on these simulations