bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growing‐error correction of ensemble Kalman filter using empirical singular vectors
Authors: Ham Yoo‐Geun , Kang In‐Sik 
Published: October 2010

AbstractIn this study, a new Ensemble Kalman Filter (EnKF) algorithm called EnKF with growing‐error correction (EnKF‐GEC) is developed for minimizing the growing component of the forecast error; for this purpose, prospective observations are assimilated using empirical singular vectors (ESVs). Unlike the Ensemble Kalman Smoother (EnKS) or four‐dimensional EnKF (4DEnKF), the EnKF‐GEC is designed to reduce the analysis error at the last analysis time (errors of initial condition for prediction). By performing assimilation experiments using the CZ‐SPEEDY coupled model within a perfect model framework, it is shown that the analysis errors obtained using the EnKF‐GEC are significantly reduced as compared to those obtained using the conventional EnKF until the last analysis time as well as during the middle of analysis time. This indicates that the new algorithm is beneficial for prediction. Seasonal prediction results show that the prediction skill when initial conditions are generated by the EnKF‐GEC is superior to when initial conditions are generated by the conventional EnKF or EnKS, particularly during the early forecast lead month. For example, correlation skill improvement with 16 ensemble members is about 0.1 for a 3‐month lead forecast. In addition, it is shown that the new EnKF algorithm is more effective for unpredictable regions, where the value of the unstable singular vector is robust. Copyright © 2010 Royal Meteorological Society
Reliability estimation in a Weibull lifetime distribution with zero‐failure field data
Authors: Jiang Ping , Lim Jae‐Hak , Zuo Ming J. , Guo Bo 
Published: October 2010

AbstractThe estimation of product reliability has attracted worldwide attention during the past several decades. The estimation procedure usually begins with parameter estimation based on test data. When there is no failure occurring in tests, traditional approaches like Maximum Likelihood Estimation (MLE) cannot be applied to estimate parameters. When product lifetime follows a Weibull distribution, to cope with this problem, we propose the modified MLE (MMLE) for estimating the parameters, based on the zero‐failure data. In this paper, we also consider the prior reliability estimate from a similar product and make use of it by incorporating it with the MMLE to construct the shrinkage preliminary test estimator (SPTE). We present the calculation method of the shrinkage factor in the SPTE, by referring to the comparison of critical quality characteristics related to product reliability, between the current batch of products and the similar (or earlier version) batch of products. Restrictions for the shrinkage factor to ensure the performance of SPTE are also discussed. The example demonstrates that the proposed SPTE of the product reliability is an effective methodology to estimate the product reliability and improve the estimation performance of the MMLE, when only zero‐failure data are available. Copyright © 2010 John Wiley & Sons, Ltd.
A navigation system for open liver surgery: design, workflow and first clinical applications
Authors: Peterhans M. , vom Berg A. , Dagon B. , Inderbitzin D. , Baur C. , Candinas D. , Weber S. 
Published: October 2010

AbstractBackgroundThe surgical treatment of liver tumours relies on precise localization of the lesions and detailed knowledge of the patient‐specific vascular and biliary anatomy. Detailed three‐dimensional (3D) anatomical information facilitates complete tumour removal while preserving a sufficient amount of functional liver tissue.MethodsWe present an easy to use, clinically applicable navigation system for efficient visualization and tool guidance during liver surgery. Accurate instrument guidance within 3D planning models was achieved with a fast registration procedure, assuming a locally rigid and temporarily static scenario. After deformations occurring during the procedure, efficient means for registration updates are provided. Special focus was given to workflow integration and the minimization of overhead time. The navigation system was validated with nine clinical cases.ResultsNavigated surgical interventions were performed with a median time overhead of 16.5 min. The navigation technology had a median accuracy of 6.3 mm, improving anatomical orientation and the detection of structures at risk.ConclusionsSuccessful application of the navigation technology to open liver surgery was achieved by minimizing the procedural complexity and optimizing integration within the existing surgical environment. The assumption of locally rigid patient registration was validated, and clinical evaluation shows clear benefits for the surgeon. Copyright © 2010 John Wiley & Sons, Ltd.
Mesohabitat use by brown trout (Salmo trutta) in a small groundwater‐dominated stream
Authors: Gosselin M.‐P. , Maddock I. , Petts G. 
Published: October 2010

ABSTRACTGroundwater‐dominated streams have particular flow regimes that commonly support populations of trout. Meso‐ and micro‐habitat surveys were carried out on a reach of the river Tern that drains a Triassic sandstone aquifer in the English West Midlands, to investigate brown trout (Salmo trutta) habitat use with varying flows. Mesohabitats were mapped over a range of summer and autumn flows and coupled with direct underwater observation (snorkelling) of fish locations together with point measurements of velocity and depth. The number of habitat types recorded was low and dominated by glides, runs, and backwaters. Brown trout showed a strong association with glides and runs with adults being more associated with runs and parr with glides. General habitat use curves showed brown trout to favour depths between 0.30 and 0.40 m and velocities below 0.40 m s−1. A clear preference was shown for sand and gravel bed materials. However, the differentiation of hydraulic habitats was weak and there was no trend in mesohabitats or change in trout use of mesohabitats with discharge. The study raises limitations of the mesohabitat survey approach when linking fish ecology, flow and physical habitat in small streams with low flow variability and low habitat diversity. In these situations, other factors (especially cover features) appear to strongly influence brown trout distribution. Copyright © 2010 John Wiley & Sons, Ltd.
Passage efficiency of offset and straight orifices for upstream movements of Iberian barbel in a pool‐type fishway
Authors: Silva A. T. , Santos J. M. , Ferreira M. T. , Pinheiro A. N. , Katopodis C. 
Published: October 2010

ABSTRACTAlthough coarse fish species are frequently the predominant taxa found in rivers, they are often neglected in fish passage studies. Detailed knowledge on the impact of hydraulics on the movements and swimming performance of these species is very limited. In this study, offset and straight orifices in a pool‐type fishway prototype were tested in terms of their suitability for Iberian barbel's (Luciobarbus bocagei) upstream movements. The effects of water velocity and turbulence descriptors on fish swimming performance were herein also analysed. Overall, the offset configuration was found to have a significantly higher rate of fish passage success (68%) than the straight arrangement (28%). The time taken to successfully negotiate the fishway was also significantly lower when it featured an offset configuration, particularly for small adults. Of all analysed hydraulic parameters, Reynolds shear stress (RSS) seemed to be the one that most strongly influenced the movements of Iberian barbel within the fishway. The findings provide evidence that the barbel's swimming performance and capacity to successfully migrate upstream through a fishway strongly depend on the arrangement of orifices and turbulence, in particular RSS, within a fish pass. More detailed research focusing on other ‘weak’ swimmers is recommended to improve future designs of pool‐type fishways suitable for other coarse species. Copyright © 2010 John Wiley & Sons, Ltd.
A framework for evaluating the spatial configuration and temporal dynamics of hydraulic patches
Authors: Wallis C. , Maddock I. , Visser F. , Acreman M. 
Published: October 2010

ABSTRACTA framework for evaluating the spatial configuration and temporal dynamics of hydraulic patches was tested in a UK lowland river. Detailed hydraulic assessment was carried out at four discharges between 0.303 m3 s−1 and 1.410 m3 s−1 in a 56 m reach. Five hydraulic patches, as combinations of depth and mean column velocity, and the transitional zones between them were delineated using fuzzy cluster analysis. The composition and configuration of the hydraulic patch mosaic was quantified using spatial metrics. Results showed that the proportion, size, shape and relative location of hydraulic patches all varied with discharge, however intermediate flows appeared to support the most diverse hydraulic patch composition and configuration. This suggests the spatial influence of mesoscale bedforms on hydraulic patches is mediated by temporal variations in discharge. Transitional areas between hydraulic patches occupied a significant proportion of the reach at all flows (33–38%) and may function as in‐stream ecotones. The framework addresses the need for a quantitative, spatially explicit approach to hydraulic assessment which could be used to assess the implications of flow regulation and hydromorphological alteration on hydraulic diversity. Copyright © 2010 John Wiley & Sons, Ltd.
Mental models, decision rules, and performance heterogeneity
Authors: Gary Michael Shayne , Wood Robert E. 
Published: October 2010

AbstractThis paper focuses on the role of managerial cognition as a source of heterogeneity in firm strategies and performance. We link differences in mental models to differences in decision rules and performance in a management simulation. Our results show more accurate mental models lead to better decision rules and higher performance. We also find that decision makers do not need accurate knowledge of the entire business environment; accurate mental models of the key principles are sufficient to achieve superior performance. A fundamental assumption in much of strategic management is that managers who have a richer understanding about organizational capabilities and the dynamics of industry structure can improve the performance of their firms. Our findings provide empirical evidence supporting this assumption and show that differences in mental models help explain ex ante why managers and firms adopt different strategies and achieve different levels of competitive success. Copyright © 2010 John Wiley & Sons, Ltd.
Governing collaborative activity: interdependence and the impact of coordination and exploration
Authors: Aggarwal Vikas A. , Siggelkow Nicolaj , Singh Harbir 
Published: October 2010

AbstractWe examine the performance implications of selecting alternate modes of governance in interorganizational alliance relationships. While managers can choose from a range of modes to govern alliances, prior empirical evidence offers limited guidance on the performance impact of this choice. We use an agent‐based simulation of interfirm decision making to complement empirical studies in this area. Our results point to a complex interplay between interdependencies, governance structures, and firms' search capabilities. Different patterns of interdependence create varying needs with respect to coordination and exploration, while at the same time different governance modes, coupled with organizational search capabilities, supply varying degrees of these factors. Firm performance in an alliance relationship improves when the needs and supplies of coordination and exploration are matched. We find situations in which stronger organizational search capabilities can backfire, leading to lower exploration within the alliance relationship, and hence to lower firm performance. Moreover, we show that for higher levels of interdependence, coordination can become more critical for firm performance than exploration: unless it is tied to coordination, exploration can be ineffective in alliance settings. Copyright © 2010 John Wiley & Sons, Ltd.
Firm resources, competitive actions and performance: investigating a mediated model with evidence from the in‐vitro diagnostics industry
Authors: Ndofor Hermann Achidi , Sirmon David G. , He Xiaoming 
Published: October 2010

AbstractBuilding on the resource‐based view (RBV) and competitive dynamics literatures, this paper proposes that considering resources or actions independently offers an incomplete understanding of the drivers of superior performance. Instead, we hypothesize that resources enable competitive actions and that when these actions leverage the firm's resources, superior performance results. We tested these hypotheses with panelized data on the technological resources and competitive actions of firms in the in‐vitro medical diagnostic substance manufacturing industry. The results provide substantial support for our hypotheses, specifically with respect to mediation. Our theory and results underscore how the integration of the competitive dynamics and RBV literatures can significantly improve our understanding of firm performance. Copyright © 2011 John Wiley & Sons, Ltd.
Moisture adsorption behavior of banana flours (Musa paradisiaca) unmodified and modified by acid‐treatment
Authors: Aguirre‐Cruz Andrés , Alvarez‐Castillo Alberto , Castrejón‐Rosales Teodoro , Carmona‐García Roselis , Bello‐Pérez Luis A. 
Published: October 2010

AbstractThe moisture sorption isotherms of untreated banana flour (UBF) and acid treated banana flours (ATBFs) were determined using the static gravimetric method of saturated salt solutions at temperatures of 30°C. The range of water activities (aw) was calculated to be between 0.14 and 0.97. The equilibrium moisture content absorption data were fitted to four sorption models that differ in the information that can be obtained from each one: Brunauer‐Emmett‐Teller equation (BET), Guggenheim, Anderson and de Boer (GAB), Smith, and Iglesias‐Chirife. Monolayer moisture content (X0) for UBF and ATBFs were found in the range of 4.06–5.47 (BET model) and 3.87–5.88 (GAB model). The GAB model was found to be the most suitable model to describe the isothermal water sorption of UBF and ATBFs in the intervals proposed of aw. TheX0values of both models (BET and GAB) increase with increasing aw. The Banana flour treated for 11 days (ATBF3) presents the highest value ofX0compared with all samples. This result suggests that mechanism of adsorption of water and molecular structure in ATBFs was affected, attributed to changes in morphology and crystallinity of the samples with treatment.
Seismic damage and fragility analysis of structures with tuned mass dampers based on plastic energy
Authors: Wong Kevin K. F. , Harris John L. 
Published: October 2010

AbstractThe effectiveness of using a tuned mass damper (TMD) to improve a structure's ability to dissipate earthquake input energy is investigated through the use of seismic fragility curves. The nonlinear material behaviour of the structure is captured using the force analogy method, the backbone for analytically quantifying plastic energy dissipation in the structure. Numerical analysis was performed to study the global response and local energy dissipation of a six‐storey moment‐resisting steel frame with and without a TMD installed for 100 simulated non‐stationary Gaussian earthquake ground motions. The effectiveness of the TMD, based on reduction of seismic responses and enhancement of the seismic fragility, is considered at structural performance levels for immediate occupancy and life safety as identified in FEMA 440. An ‘equivalent monotonic plastic strain’ approach—a local measure of structural damage—is used to correlate the seismic fragilities at different global performance levels based on storey drift. Results illustrate that a TMD can enhance the structure's ability to dissipate energy at low levels of earthquake shaking, while less effective during moderate to strong earthquakes, which can cause a significant period shift associated with major structural damage. This ‘de‐tuning’ effect suggests that an extremely sizable TMD is not effective in reducing damage of a structure. Published in 2010 by John Wiley & Sons, Ltd.
Experimental study for seismic retrofit of non‐seismic designed reinforced concrete structures
Authors: Park Tae Won , Na Ung Jin , Chung Lan 
Published: October 2010

AbstractAn evaluation of seismic performance was conducted for a reinforced concrete (RC) structure designed without seismic considerations. The seismic performances of many existing structures are often inadequate based on the current seismic design codes, and it is sure that this is the general tendency in most countries.Six specimens were designed and constructed to simulate RC frames built in the 1980s, before the introduction of earthquake‐resistance design provisions in South Korea. The specimens were composed of one control specimen without any retrofit and five specimens retrofitted using wire‐bracing, brick infill wall, steel bracing (X‐ and K‐type) and corner gusset plate. All retrofitted specimens show significant increase in strength and ductility. The behaviours of each specimen are compared in the view of maximum strength, maximum moment, stiffness and energy dissipation capacity. Overall, efficiency analysis was also demonstrated in this study. Copyright © 2010 John Wiley & Sons, Ltd.
Added value of three‐/four‐dimensional ultrasound in offline analysis and diagnosis of congenital heart disease
Authors: Yagel S. , Cohen S. M. , Rosenak D. , Messing B. , Lipschuetz M. , Shen O. , Valsky D. V. 
Published: October 2010

AbstractObjectiveMany published studies have shown that application of three‐dimensional (3D) and real‐time 3D (4D) ultrasound modalities can improve certain aspects of fetal echocardiography, but have left open the question of whether these modalities improved the accuracy of prenatal detection of anatomical fetal cardiovascular malformations. We aimed to determine whether 3D/4D ultrasound improved diagnostic ability in cases of congenital heart disease (CHD).MethodsWomen who attended for early‐ or midtrimester targeted organ scans had complete fetal echocardiography according to our five‐planes protocol, as well as examination of the ductus venosus and longitudinal aortic arch planes, performed with 2D ultrasound combined with 2D color Doppler, spatiotemporal image correlation (STIC), STIC with color Doppler, and STIC with B‐flow. Ultrasound data of cases of CHD were stored in a dedicated archive. Stored cases were anonymized and the list order was randomized. Stored 2D ultrasound cineloops and 4D ultrasound volumes were reviewed separately according to a standardized table of 23 specified structures on five required planes of visualization: the upper abdomen, four‐chamber view, five‐chamber view, pulmonary artery bifurcation view, and three vessels and trachea plane. Separate diagnoses were recorded and finally compared. Diagnoses were confirmed by pathological examination or neonatal echocardiography.ResultsDuring the study period, 13 101 examinations were performed; 181 diagnoses of CHD were made. In 12 of these, 3D/4D ultrasound added to the accuracy of our diagnosis: one right aortic arch with anomalous branching; one transposition of the great arteries with pulmonary atresia diagnosed with tomographic ultrasound imaging (TUI); one segmental interrupted aortic arch diagnosed with TUI; one right ventricle aneurysm diagnosed with B‐flow; two agenesis of ductus venosus to the coronary sinus diagnosed by multiplanar reconstruction (MPR) and B‐flow; two total anomalous pulmonary venous connection diagnosed with MPR; and four ventricular septal defect (VSD) diagnosed with the aid of virtual planes. There were 12 missed diagnoses and no false‐positive results.Conclusions3D/4D ultrasound modalities may have advantages in some aspects of fetal cardiovascular evaluation, however, overall 3D/4D ultrasound modalities had added value in only about 6% of cases of fetal anatomical cardiovascular anomalies. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Non‐invasive prediction of intra‐amniotic inflammation in women with preterm labor
Authors: Jung H. J. , Park K. H. , Kim S. N. , Hong J.‐S. , Oh K. J. , Kim G. , Kwon J. Y. 
Published: October 2010

AbstractObjectiveTo develop a model based on non‐invasive variables to predict the probability of intra‐amniotic inflammation in women with preterm labor and intact membranes.MethodsTransvaginal ultrasonography and digital examination for the assessment of cervical length and cervical dilatation were performed, and maternal blood was collected for the determination of C‐reactive protein and white blood cell (WBC) count immediately after amniocentesis in 153 consecutive women with preterm labor. Amniotic fluid obtained by amniocentesis was cultured for aerobic and anaerobic bacteria and mycoplasmas, and the WBC was determined. Intra‐amniotic inflammation was defined as an elevated amniotic fluid interleukin‐6 concentration (> 2.6 ng/mL). Receiver–operating characteristics (ROC) curves and logistic regression analysis were used for statistical analysis.ResultsThe prevalence of a positive amniotic fluid culture was 7.2% (11/153) and the prevalence of intra‐amniotic inflammation was 19.6% (30/153). The final logistic regression model was based on non‐invasive clinical variables, including gestational age at assessment, cervical length and maternal blood WBC count, which were the best predictors of intra‐amniotic inflammation. The model was shown to have an adequate goodness of fit (P = 0.754), and the area under the ROC curve was 0.724, indicating reasonably good discrimination.ConclusionIn women with preterm labor and intact membranes, the risk for intra‐amniotic inflammation can be predicted non‐invasively with a risk score based on gestational age, cervical length and maternal blood WBC count. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Motion perception: behavior and neural substrate
Authors: Mather George 
Published: October 2010

AbstractVisual motion perception is vital for survival. Single‐unit recordings in primate primary visual cortex (V1) have revealed the existence of specialized motion sensing neurons; perceptual effects such as the motion after‐effect demonstrate their importance for motion perception. Human psychophysical data on motion detection can be explained by a computational model of cortical motion sensors. Both psychophysical and physiological data reveal at least two classes of motion sensor capable of sensing motion in luminance‐defined and texture‐defined patterns, respectively. Psychophysical experiments also reveal that motion can be seen independently of motion sensor output, based on attentive tracking of visual features. Sensor outputs are inherently ambiguous, due to the problem of univariance in neural responses. In order to compute stimulus direction and speed, the visual system must compare the responses of many different sensors sensitive to different directions and speeds. Physiological data show that this computation occurs in the visual middle temporal (MT) area. Recent psychophysical studies indicate that information about spatial form may also play a role in motion computations. Adaptation studies show that the human visual system is selectively sensitive to large‐scale optic flow patterns, and physiological studies indicate that cells in the middle superior temporal (MST) area derive this sensitivity from the combined responses of many MT cells. Extraretinal signals used to control eye movements are an important source of signals to cancel out the retinal motion responses generated by eye movements, though visual information also plays a role. A number of issues remain to be resolved at all levels of the motion‐processing hierarchy. WIREs Cogni Sci 2011 2 305–314 DOI: 10.1002/wcs.110Additional Supporting Information may be found in http://www.lifesci.sussex.ac.uk/home/George_Mather/Motion/index.htmlThis article is categorized under:

Psychology > Perception and Psychophysics