bluuebunny/crossref_metadata_2025_split huggingface dataset:
Object identification based on uncertain sparse sensor information
Authors: Kawashima Toshio , Shirakawa Yoichi , Aoki Yoshinao 
Published: March 2014

AbstractThis paper discusses the problem of object identification based on spatially sparse uncertain information. First, it is assumed that the sensor information is composed of two kinds of information, i.e., the geometrical parameter distribution and the decision tree. The description format for the uncertain sensor information is defined. Then a method is presented where the set of uncertain sensor information obtained by the measurement of the object is combined (fusion), and the match between the object and the model is examined. Finally, the case of measurement of the two‐dimensional figure by the sparse shape sensor is considered. The process of fusion is demonstrated and the usefulness of the proposed method is shown by a matching experiment.In the proposed method, an object identification procedure is employed where the information obtained from several sensors is described as geometrical parameters together with their error distributions, and the match to the model is examined by combining those parameters. The information, for which more than one decision tree interpretation is possible, is described as the basic probability of the Dempster‐Shafer theory. The parameters are fused for each interpretation, and the reliability of the result of fusion is estimated by the combination rule. As a simulation experiment, the case with the tactile sensor in contact with a column object is considered, and the object identification process is demonstrated.
Scale‐space filtering for periodic waveforms
Authors: Wada Toshikazu , Gu Yi He , Sato Makoto 
Published: March 2014

AbstractScale‐space filtering is one of the hierarchical representations of the waveform in which the given waveform is observed in multiscale measurement. Scale‐space filtering using the Gaussian filter, whose bandwidth varies with the scale, continuously blurs the waveform. It has a property that the number of zero crossings of the waveform decreases monotonically while increasing the scale. This property is called monotonicity.The relations among intervals sectioned by zero crossings are represented by a tree structure. Thus, most of the past studies on the scale‐space filtering can be viewed as the studies of the waveforms in (‐∞, ∞). However, there has been no adequate discussion on the scale‐space filtering of the periodic waveform.This paper describes a method to construct scale‐space filtering so that the monotonicity of the zero crossings applies also to the periodic waveform. By analyzing the zero crossings of the waveform, essential differences between the ordinary scale‐space filtering and the periodic scale‐space filtering are indicated. An example is presented for the structural analysis of the speech waveform, and the difference between the hierarchical structures derived by those scale‐space filters is discussed.
Quantile regression analysis of length‐biased survival data
Authors: Wang Huixia Judy , Wang Lan 
Published: March 2014

AbstractLength‐biased time‐to‐event data commonly arise in epidemiological cohort studies and cross‐sectional surveys. Ignoring length‐biased sampling often leads to severe bias in estimating the survival time in the general population. We propose a flexible quantile regression framework for analysing the covariate effects on the population survival time under both length‐biased sampling and random censoring. This framework allows for easy interpretation of the statistical model. Furthermore, it allows the covariates to have different impacts at different tails of the survival distribution and thus is able to capture important population heterogeneity. Using an unbiased estimating equation approach, we develop a new estimator that allows the censoring variable to depend on covariates in a non‐parametric way. We establish the consistency and asymptotic normality for the proposed estimator. A lack‐of‐fit test is proposed for diagnosing the adequacy of the population quantile regression model. The finite sample performance of the proposed methods is assessed through a simulation study. We demonstrate that the proposed method is effective in discovering interesting covariate effects by analysing the Canadian Study of Health and Aging dementia data. Copyright © 2014 John Wiley & Sons Ltd
A review of PEM fuel cell durability: materials degradation, local heterogeneities of aging and possible mitigation strategies
Authors: Dubau Laetitia , Castanheira Luis , Maillard Frédéric , Chatenet Marian , Lottin Olivier , Maranzana Gaël , Dillet Jérôme , Lamibrac Adrien , Perrin Jean‐Christophe , Moukheiber Eddy , ElKaddouri Assma , De Moor Gilles , Bas Corine , Flandin Lionel , Caqué Nicolas 
Published: March 2014

Through a tight collaboration between chemical engineers, polymer scientists, and electrochemists, we address the degradation mechanisms of membrane electrode assemblies (MEAs) during proton exchange membrane fuel cell (PEMFC) operation in real life (industrial stacks). A special attention is paid to the heterogeneous nature of the aging and performances degradation in view of the hardware geometry of the stack and MEA. Macroscopically, the MEA is not fuelled evenly by the bipolar plates and severe degradations occur during start‐up and shut‐down events in the region that remains/becomes transiently starved in hydrogen. Such transients are dramatic to the cathode catalyst layer, especially for the carbon substrate supporting the Pt‐based nanoparticles. Another level of heterogeneity is observed between the channel and land areas of the cathode catalyst layer. The degradation of Pt3Co/C nanocrystallites employed at the cathode cannot be avoided in stationary operation either. In addition to the electrochemical Ostwald ripening and to crystallite migration, these nanomaterials undergo severe corrosion of their high surface area carbon support. The mother Pt3Co/C nanocrystallites are continuously depleted in Co, generating Co2+ cations that pollute the ionomer and depreciate the performance of the cathode. Such cationic pollution has also a negative effect on the physicochemical properties of the proton‐exchange membrane (proton conductivity and resistance to fracture), eventually leading to hole formation. These defects were localized with the help of an infrared camera. The mechanical fracture‐resistance of various perfluorosulfonated membranes further demonstrated that polytetrafluoroethylene‐reinforced membranes better resist hole formation, due to their high resistance to crack initiation and propagation. WIREs Energy Environ 2014, 3:540–560. doi: 10.1002/wene.113This article is categorized under:

Fuel Cells and Hydrogen > Science and Materials
Fuel Cells and Hydrogen > Systems and Infrastructure
Energy Research & Innovation > Science and Materials
Effects of intensity and seasonal timing of disturbances on a rocky intertidal benthic community on the southern coast of Korea
Authors: Kim Sangil , Kang Yun Hee , Choi Chang Jae , Won Nam‐Il , Seo In‐Soo , Lee Hyuk Je , Jung Sukgeun , Park Sang Rul 
Published: March 2014

AbstractThe effects of intensity and timing of disturbances on recovery of marine benthic organisms were investigated on a rocky intertidal shore in Gwangyang Bay, Korea. We hypothesized that the recovery pattern of the benthic community structure would be affected by disturbance intensity and season. Twenty‐eight permanent plots were set up, with disturbance intensity (cleared plots and sterile plots) and seasonal disturbance (fall 1999 and spring 2000) incorporated into the experimental design. To monitor natural seasonal variation in benthic community abundances, we established seven permanent unmanipulated plots. Turf‐forming algae were observed in the unmanipulated plots throughout the experimental period, whereas green algae and invertebrate presence varied with season. In the disturbance‐intensity experiment, turf‐forming and green algae were dominant in cleared plots. The highest coverage of sessile organisms was observed in sterile plots, which exhibited the highest species richness because of their relatively low macroalgal coverage. Seasonal effects of disturbance were an important factor in the recovery pattern of benthic organisms under high disturbance intensity. Coverage of green algae was higher in sterile spring plots than in sterile fall plots; this result was attributed to low spatial competition, as the disturbances occurred just before green algal blooms. On the other hand, the abundances of barnacles and bivalves were highest on sterile fall plots, as these organisms were suppressed by green algal blooms in other periods. These results indicate that the effects of disturbance intensity on benthic community recovery patterns can be influenced by season of disturbance.
Effective conditions for the reflection of an acoustic wave by low-porosity perforated plates
Authors: Laurens S. , Piot E. , Bendali A. , Fares M’B. , Tordeux S. 
Published: March 2014

AbstractThis paper describes an investigation of the acoustic properties of a rigid plate with a periodic pattern of holes, in a compressible, ideal, inviscid fluid in the absence of mean flow. Leppington & Levine (J. Fluid Mech., vol. 61, 1973, pp. 109–127) obtained an approximation of the reflection and transmission coefficients of a plane wave incident on an infinitely thin plate with a rectangular array of perforations, assuming that a characteristic size of the perforations is negligible relative to that of the unit cell of the grating, itself assumed to be negligible relative to the wavelength. One part of the present study is of methodological interest. It establishes that it is possible to extend their approach to thick plates with a skew grating of perforations, thus confirming recent results of Bendali et al. (SIAM J. Appl. Math., vol. 73 (1), 2013, pp. 438–459), but in a much simpler way without using complex matched asymptotic expansions of the full wave or to a grating of multipoles. As is well-known, effective compliances for the plate can then be derived from the corresponding approximations of the reflection and transmission coefficients. These compliances are expressed in terms of the Rayleigh conductivity of an isolated perforation. Consequently, in one other part of the present study, the methodology recently introduced by Laurens et al. (ESAIM, Math. Model. Numer. Anal., vol. 47 (6), 2013, pp. 1691–1712) to obtain sharp bounds for the Rayleigh conductivity has been extended to include the case for which the openings of the perforations on the upper and lower sides of the plate are elliptical in shape. This not only enables the determination of these bounds and of the associated reflection and transmission coefficients for actual plates with tilted perforations but also yields single expressions covering all usual cases of perforations: straight or tilted with a circular or an elliptical cross-section.
On precessing flow in an oblate spheroid of arbitrary eccentricity
Authors: Zhang Keke , Chan Kit H. , Liao Xinhao 
Published: March 2014

AbstractWe consider a homogeneous fluid of viscosity$\nu $confined within an oblate spheroidal cavity of arbitrary eccentricity$\mathcal{E}$marked by the equatorial radius$d$and the polar radius$d \sqrt{1-\mathcal{E}^2}$with$0<\mathcal{E}<1$. The spheroidal container rotates rapidly with an angular velocity${\boldsymbol{\Omega}}_0 $about its symmetry axis and precesses slowly with an angular velocity${\boldsymbol{\Omega}}_p$about an axis that is fixed in space. It is through both topographical and viscous effects that the spheroidal container and the viscous fluid are coupled together, driving precessing flow against viscous dissipation. The precessionally driven flow is characterized by three dimensionless parameters: the shape parameter$\mathcal{E}$, the Ekman number${\mathit{Ek}}=\nu /(d^2 \delimiter "026A30C {\boldsymbol{\Omega}}_0\delimiter "026A30C )$and the Poincaré number${\mathit{Po}}=\pm \delimiter "026A30C {\boldsymbol{\Omega}}_p\delimiter "026A30C / \delimiter "026A30C \boldsymbol{\Omega}_0\delimiter "026A30C $. We derive a time-dependent asymptotic solution for the weakly precessing flow in the mantle frame of reference satisfying the no-slip boundary condition and valid for a spheroidal cavity of arbitrary eccentricity at${\mathit{Ek}}\ll 1$. No prior assumptions about the spatial–temporal structure of the precessing flow are made in the asymptotic analysis. We also carry out direct numerical simulation for both the weakly and the strongly precessing flow in the same frame of reference using a finite-element method that is particularly suitable for non-spherical geometry. A satisfactory agreement between the asymptotic solution and direct numerical simulation is achieved for sufficiently small Ekman and Poincaré numbers. When the nonlinear effect is weak with$\delimiter "026A30C {\mathit{Po}}\delimiter "026A30C \ll 1$, the precessing flow in an oblate spheroid is characterized by an azimuthally travelling wave without having a mean azimuthal flow. Stronger nonlinear effects with increasing$\delimiter "026A30C {\mathit{Po}}\delimiter "026A30C $produce a large-amplitude, time-independent mean azimuthal flow that is always westward in the mantle frame of reference. Implications of the precessionally driven flow for the westward motion observed in the Earth’s fluid core are also discussed.
Coupling of surface water and groundwater nitrate-N dynamics in two permeable agricultural catchments
Authors: MELLANDER P.-E. , MELLAND A. R. , MURPHY P. N. C. , WALL D. P. , SHORTLE G. , JORDAN P. 
Published: March 2014

SUMMARYThe current study investigated the coupling of groundwater and surface water nitrogen (N) dynamics over 3 years, and considered intensive agricultural land-management influences over this period where the risk of N loss to water was considered high. Groundwater N (as nitrate) was monitored monthly in different strata and zones in four hillslopes, two in each of two agricultural catchments ofc. 10 km2, and stream water N flux was monitored sub-hourly in the catchment outlets. Field nutrient sources were connected to surface waterviagroundwater; the groundwater along hillslopes was seen to be influenced spatially and temporally by management, geology and weather as observed in the concentration variability of nitrate in groundwater. Based on spatio-temporal averages of nitrate-N concentration, groundwater status was considered good (at least below a maximum acceptable concentration (MAC) of 11·3 mg/l). However, zones coincident with land-use change (ploughing and reseeding, typical of a management event in intensive landscapes), showed high spatio-temporal variability in nitrate-N concentration, exceeding the MAC temporarily, before recovering. This spatio-temporal variability highlighted the need for insight into these differences when interpreting groundwater quality data from a limited number of basin-scale sampling points and occasions. In both catchments the 3-year mean nitrate-N concentration in stream water was similar to the spatio-temporal mean concentration in groundwater. The magnitude and variability of loads, however, were more related to changes in annual runoff rather than changes in annual groundwater nitrate-N status. In one wet year, nitrate-N loads exceeded 48 kg/ha from an Arable catchment and 45 kg/ha from a grassland catchment (close to double the loss in a dry year).
Dynamics of bovine intramammary infections due to coagulase-negative staphylococci on four farms
Authors: Bexiga Ricardo , Rato Márcia G. , Lemsaddek Abdelhak , Semedo-Lemsaddek Teresa , Carneiro Carla , Pereira Helena , Mellor Dominic J , Ellis Kathryn A , Vilela Cristina L 
Published: March 2014

The objectives of this study were to compare the impact of different coagulase-negative species (CNS) on udder health measured in terms of individual quarter milk somatic cell count (SCC) and duration of intramammary infection, and to get some insight into most likely routes of infection for different CNS species. This longitudinal observational study was performed on four farms that were sampled at 4-week intervals for a total of 12 visits each. Quarters infected with CNS were followed through time with milk samples being submitted for bacteriological culture and SCC determination. PCR amplification of the internal transcribed spacer region and sequencing of the sodA and rpoB genes were used for species allocation. Pulsed-field gel electrophoresis (PFGE) was performed to assess strain identity. The percentage of quarters affected per farm varied between 6 and 35%, with the most frequently isolated CNS species being Staphylococcus epidermidis, followed by Staph. simulans, Staph. chromogenes and Staph. haemolyticus. It was possible to follow 111 intramammary infections due to CNS through time. Duration of infection had a mean of 188 d and was not significantly different between CNS species. Geometric mean quarter SCC overall was 132 000 cells/ml and was also not significantly different between CNS species. Despite the possibility of a different epidemiology of infection, the impact in terms of udder health seems to be similar for different CNS species.
Effects of overmilking and liner type and characteristics on teat tissue in small ruminants
Authors: Alejandro Manuel , Roca Amparo , Romero Gema , Díaz José-Ramón 
Published: March 2014

The aim of this work was to study the effect on teat wall thickness and canal length in sheep and goats of overmilking for 2 min (OM+2) and of milking with used (AL; +3000 milkings) and twisted (TL; 45°) liners in sheep and goats, as well as the effect of milking goats with liners designed for sheep (SL, shorter length and diameter than liners for goats). To this end, we performed four experiments in goats and three in sheep, in a Latin square design with two experimental periods. During the experimental period 4 controls were carried out, performing ultrasound scans before and immediately after milking to determine the teat wall thickness (TWT), teat wall area (TWA), teat end area (TEWA) and teat canal length (TCL). OM+2 caused a significant increase in TWT, TWA, TEWA and TCL in goats and in TWA, TEWA and TCL in sheep. Liner features had a strong influence on the variables studied; aged liners caused significant changes in TWT and TCL in goats and in TWT in sheep; twisted liners produced a significant effect on the increase of TWT and TCL in goats, without reaching significance level in sheep; and milking goats with sheep liners led to a significant increase in TWT, TWA, TEWA and TCL. In practice, it is therefore important to avoid overmilking and the use of worn-out liners. It is also necessary to use liners designed for the morphological features of each species, taking special care to carry out periodic liner positioning revisions to ensure the benefits of pulsation on the teat end. Finally, it would be necessary to carry out long-term experiments to study whether the increase in thickness observed in some experiments is sufficient to affect milking efficiency and mammary gland health status.
IX.—Water Movements in the Tay Estuary
Authors: West J. R. 
Published: March 2014

SynopsisThe present poor understanding of the fundamental mechanisms of estuarine water movement necessitates an empirical or semi-empirical approach to the circulation problem.The Tay estuary may be considered as a system for which the inputs consist of phenomena of marine and fluvial origin, and the output is the resultant fluid motion. The definition of the boundaries of the system and of the inputs is explained. The functional dependence of fluid motion is examined with respect to the existing knowledge of estuarine circulation and the economic and technological difficulties associated with prototype estuarine investigations. The results of these studies formed the basis for planning a field study of the Tay estuary.Data collected during the year 1969-70 has permitted the formulation of empirical relationships between parametric forms of the input and output variables. Thus, to a first approximation, the parameters of estuarine water motion can be predicted for particular antecedent input conditions.
XIII.—The Fisheries of the Forth–Tay Estuaries
Authors: Thomas H. J. , Saville A. 
Published: March 2014

SynopsisThe most valuable species are Nephrops, salmon, haddock, lobster and sprat. Demersal fish, haddock, whiting, cod, plaice and lemon sole, are mainly taken by seine-netters and light trawlers from 40 to 70 ft overall length. Landings of cod and lemon sole have declined, as has fishing effort. The estuarine environment is especially important for plaice and cod, which spend their early life in coastal waters. Pelagic fish, herring, sprat and mackerel, are unimportant but occasionally pair-trawling for sprats occupies up to 75 boats. Nephrops trawlers, from 40 to 55 ft, fish mainly west of May Island. The Nephrops stocks are heavily exploited. Creel fishing for lobster and crab supports 85 boats. The lobster stocks are intensively fished and landings have decreased. Periwinkles and mussels are gathered but shrimps, though present, are not exploited. Landings of salmon and sea trout, mainly by net and coble from the estuaries, are important chiefly in the Tay. The fisheries have changed dramatically in the past century. Those for herring, oysters and queens have ceased whilst new fisheries have developed for Nephrops and sprat.
The Distribution of Bottom Sediments in Loch Leven, Kinross
Authors: Calvert S. E. 
Published: March 2014

SynopsisThe sediments of shallow and deep water areas of Loch Leven are, respectively, medium to very fine-grained sands and silty clays (muds). The largest area of more or less uniform sediment type (sands) occurs on the north-eastern shelf. The sediments with the finest grain size are found in an area to the south and east of Castle Island and Reed Bower. Here, the median grain size is less than 4 microns. The amount of sand in a sediment is very highly correlated with the median grain size of the sediment and may therefore most usefully be used to describe the general distribution of sediments in the loch. The distribution of organic carbon in the loch sediments is largely confined to deep-water areas. The southern deep area is more organic rich than the northern deep area. The amount of organic carbon in a sediment is positively correlated with the amounts of clay and silt in the sediment.
Preliminary Comparative Studies on Denitrification and Methane Production in Loch Leven, Kinross, and other Freshwater Lakes
Authors: Johnston D. W. , Holding A. J. , McCluskie J. E. 
Published: March 2014

SynopsisData on the evolution of nitrogen gas and methane, and the utilisation of nitrate were obtained from sediment-water interface core samples obtained from Loch Leven, Kinross, and Windermere Esthwaite Water, Coniston Water and Ennerdale Water in the English Lake District. Differences in the rate of evolution and total quantity of the gases are discussed in relation to the trophic state of the lakes. The potential importance of nitrogen gas loss to the nitrogen budget of the lakes is considered.
The Algal Plankton of Loch Leven, Kinross
Authors: Bailey-Watts A. E. 
Published: March 2014

SynopsisThe species composition and succession of the algal plankton are described. Population density changes, as indicated by chlorophylla, cell volume and numbers are discussed in relation to physical, chemical and biological factors in the environment.The quality and the amounts of the plankton vary considerably from year to year. However, for most of the period reviewed it has been dominated by dense developments of nanno and other small algae belonging to the diatom and blue-green groups.Factors of particular importance affecting the high observed biomass and production include the water depth, adequate mixing and a rich supply of nutrients from the inflows and the sediments. Competition from other green plants appears to be low. Utilisation of living algal cells in the plankton by crustacean and protozoan grazing and fungal parasitism is rarely important.The composition of the phytoplankton is discussed in relation to the eutrophic nature of the loch.