Merging Time Research Articles

A software to merge temperature and salinity profiles with climatology

Temperature and salinity are two major parameters deciding the characteristics of the ocean water column. Accurate information of these parameters is always a pre-requisite for any study of major climatic/physical processes. The insitu measurement of these parameters is done using instruments such as XBT, XCTD and CTD. Most of the instances, the data will not be collected upto the bottom depth due to instrument or time limitations. In such cases, the collected profiles are artificially extended up to ocean bottom, which is not always true. A better option is to extract the profile upto bottom by blending the insitu profile with climatology.The Profile blending software, written in Visual Basic, is for merging real time insitu temperature and salinity profiles with the climatology profiles for providing the data from surface to bottom. This s/w provides a smoother transition of gradient across the merge point without disturbing the insitu data. It also provides the climatological salinity profile for the corresponding near real time temperature profile obtained from expendable bathythermograph (XBT) records.

Effect of a risk factor in convoy merging manoeuvres considering uncertainty in travelling times

Cooperative guiding, and especially in convoys, for automated, non-contaminating transport units is a line of research for sustainable urban transport. In this paper we propose a strategy for facilitating the merging manoeuvre between independent units travelling in a transport scenario (usually a city) and a convoy following a pre-defined peripheral trajectory in the same scenario. The proposal consists of an inexpensive computational cost algorithm, which is able to calculate the optimal merging point and the efficient route to reach it. An optimal merging node is the one on the periphery which minimises the merging time. In addition to the complexity of the problem is the uncertainty associated to travelling times, as is habitual in a real urban setting. Sources of uncertainty include weather conditions, the effect of the zone (proximity to centres of social services or cultural interest), the day and time on traffic density, etc. All this justifies the variability in the time taken by any vehicle moving along a section in the transport scenario.In order to delimit the randomness inherent to the problem, the authors incorporate a novel “risk factor” parameter, which conditions the solution. This risk factor limits the probability of a convoy reaching the merging node before the pursuer (failed merging manoeuvre).The possibility of having the travelling experiences from any unit moving in the transport scenario means that the statistics (mean and variance) associated to the expected travelling times can be updated dynamically. This task is executed in a remote centre which communicates with all the units in the transport scenario. This dynamic updating means that the objectives (optimal merging node and efficient routing) can be re-evaluated, and makes it possible to adapt to the changing conditions of the transport scenario, each time the pursuing unit reaches an intermediate node.In order to validate the algorithm described in this paper and evaluate the effect of the aforementioned novel risk factor, we have tested them on a simulated transport scenario using Player/Stage. The results and conclusions are also shown.

A Novel Fusion Method for Dynamic Updating in Inverted Index Establishment

The establishment of inverted index is the main content of index system. In this paper, we propose a novel fusion method using dynamic updating. Firstly, the establishing process of the inverted index is introduced. Secondly, the regimes of the dynamic updating for hash lists based index are discussed in details. Experimental results show that this method can save index merging time as well as spare some memory space.

GENERATION OF HIGH RESOLUTION AND HIGH PRECISION ORTHORECTIFIED ROAD IMAGERY FROM MOBILE MAPPING SYSTEM

Abstract. In this paper, a novel technique to generate a high resolution and high precision Orthorectified Road Imagery (ORI) by using spatial information acquired from a Mobile Mapping System (MMS) is introduced. The MMS was equipped with multiple sensors such as GPS, IMU, odometer, 2-6 digital cameras and 2-4 laser scanners. In this study, a Triangulated Irregular Network (TIN) based approach, similar to general aerial photogrammetry, was adopted to build a terrain model in order to generate ORI with high resolution and high geometric precision. Compared to aerial photogrammetry, there are several issues that are needed to be addressed. ORI is generated by merging multiple time sequence images of a short section. Hence, the influence of occlusion due to stationary objects, such as telephone poles, trees, footbridges, or moving objects, such as vehicles, pedestrians are very significant. Moreover, influences of light falloff at the edges of cameras, tone adjustment among images captured from different cameras or a round trip data acquisition of the same path, and time lag between image exposure and laser point acquisition also need to be addressed properly. The proposed method was applied to generate ORI with 1 cm resolution, from the actual MMS data sets. The ORI generated by the proposed technique was more clear, occlusion free and with higher resolution compared to the conventional orthorectified coloured point cloud imagery. Moreover, the visual interpretation of road features from the ORI was much easier. In addition, the experimental results also validated the effectiveness of proposed radiometric corrections. In occluded regions, the ORI was compensated by using other images captured from different angles. The validity of the image masking process, in the occluded regions, was also ascertained.

Control of Vortex Merging Induced From Diocotron Instability Using Rotating-Wall Electric Fields

Two-dimensional particle-in-cell simulation in a cylindrical geometry shows that the vortex formation and merging of a magnetically confined pure electron column are controllable with rotating-wall electric fields. With an optimized frequency, the vortex merging time can be extended longer than that without rotating fields.

Laparoscopic Anterior Hemifundoplication Improves Key Symptoms Without Impact on GE in Children With and Children Without Neurodevelopmental Delays

We investigated the impact of laparoscopic anterior hemifundoplication on gastric emptying (GE) and specific symptoms in children with and children without neurodevelopmental delays gastroesophageal reflux. Scintigraphic and ultrasonographic GE measurements were correlated. Twenty-six children (mean age 7 ± 6.1 years), of whom 14 were neurodevelopmentally delayed, were evaluated prospectively before 3 and 6 months after laparoscopic anterior hemifundoplication. All of the patients underwent clinical assessments, interviews, and 24-hour pH monitoring. Key symptoms were evaluated using a 5-point Likert scale. Gastric emptying was assessed by Tc-99m-DTPA-scintigraphy and ultrasonography. All of the children had significant catch-up growth after fundoplication, which was more pronounced in the neurologically normal children (P < 0.05 vs impaired), in line with a decrease in the use of omeprazol (mean 0.93 ± 0.7 mg · kg(-1) · day(-1) before and 0.06 ± 0.18 mg · kg(-1) · day(-1) at 6 months after operation; P < 0.001). The 24-hour pH monitoring normalized in all of the children, and the mean severity of the key symptoms such as vomiting, choking, and pain was significantly reduced (P < 0.001). Scintigraphic GE parameters, such as the elimination rate/minute, gastric half-emptying time (t1/2), gastric residual activity (RA), and duration of the initial merging time, were not altered significantly by the operation (P > 0.05). Ultrasonographic evaluations confirmed these results [positive correlation with scintigraphy for t1/2 (P = 0.006) and RA (P = 0.01)]. The symptoms evolution and GE were uncorrelated (P > 0.01). There were no significant differences between children with and children without neurodevelopmental delays. Laparoscopic anterior hemifundoplication achieves an excellent symptomatic outcome without affecting GE in children with and children without neurodevelopmental delays.

Simulation on motion of particles in vortex merging process

In a two-phase flow, the vortex merging influences both the flow evolution and the particle motion. With the blobs-splitting-and-merging scheme, the vortex merging is calculated by a corrected core spreading vortex method (CCSVM). The particle motion in the vortex merging process is calculated according to the particle kinetic model. The results indicate that the particle traces are spiral lines with the same rotation direction as the spinning vortex. The center of the particle group is in agreement with that of the merged vortex. The merging time is determined by the circulation and the initial ratio of the vortex radius and the vortex center distance. Under a certain initial condition, a stretched particle trail is generated, which is determined by the viscosity, the relative position between the particles and the vortex, and the asymmetrical circulation of the two merging vortices.

The effect of gas dynamics on semi-analytic modelling of cluster galaxies

We study the degree to which non-radiative gas dynamics affect the merger histories of haloes along with subsequent predictions from a semi-analytic model (SAM) of galaxy formation. To this aim, we use a sample of dark matter only and non-radiative smooth particle hydrodynamics (SPH) simulations of four massive clusters. The presence of gas-dynamical processes (e.g. ram pressure from the hot intra-cluster atmosphere) makes haloes more fragile in the runs which include gas. This results in a 25 per cent decrease in the total number of subhaloes at z = 0. The impact on the galaxy population predicted by SAMs is complicated by the presence of 'orphan' galaxies, i.e. galaxies whose parent substructures are reduced below the resolution limit of the simulation. In the model employed in our study, these galaxies survive (unaffected by the tidal stripping process) for a residual merging time that is computed using a variation of the Chandrasekhar formula. Due to ram-pressure stripping, haloes in gas simulations tend to be less massive than their counterparts in the dark matter simulations. The resulting merging times for satellite galaxies are then longer in these simulations. On the other hand, the presence of gas influences the orbits of haloes making them on average more circular and therefore reducing the estimated merging times with respect to the dark matter only simulation. This effect is particularly significant for the most massive satellites and is (at least in part) responsible for the fact that brightest cluster galaxies in runs with gas have stellar masses which are about 25 per cent larger than those obtained from dark matter only simulations. Our results show that gas dynamics has only a marginal impact on the statistical properties of the galaxy population, but that its impact on the orbits and merging times of haloes strongly influences the assembly of the most massive galaxies.

EQUAL- AND UNEQUAL-MASS MERGERS OF DISK AND ELLIPTICAL GALAXIES WITH BLACK HOLES

We present binary galaxy merger simulations with varying mass ratios and different progenitor morphologies. The simulations include mergers of gas-rich disks (Sp-Sp), of early-type galaxies and disks (E-Sp, mixed mergers), and mergers of early-type galaxies (E-E, dry mergers). We follow the dynamics of gas, stars, and dark matter, and include radiative cooling, star formation and black hole (BH) accretion, and the associated feedback processes as in Springel et al. We study the mass assembly of the BHs and discuss technical issues of the implemented model in detail. For Sp-Sp mergers, the peak star formation rate and BH accretion rate decrease and the growth timescales of the central BHs and newly formed stars increase with higher progenitor mass ratios. The peak BH accretion rate typically occurs shortly after the time of BH merging for low progenitor mass ratios (e.g., 3:1 and lower), whereas for higher progenitor mass ratios there is no clear correlation between the peak BH accretion rate and the BH merging time. The termination of star formation by BH feedback in disk mergers is significantly less important for higher progenitor mass ratios (e.g., 3:1 and higher). In addition, the inclusion of BH feedback efficiently suppresses star formation in dry E-E mergers and mixed E-Sp mergers. All merger remnants, independent of their progenitors, follow the observed relations between the central BH mass and the stellar velocity dispersion (MBH − σ), the bulge mass (MBH − M*), and the bulge binding energy (MBH − M*σ2), with the dominant source of scatter arising from variations in the initial gas mass fraction. The normalizations for all relations and the simulated slope of the MBH − σ and MBH − M*σ2 relations are in good agreement with the observations, whereas the simulated slope of the MBH − M* relation is slightly steeper compared to the observations. This indicates that the simple BH feedback model self-regulates the mass growth of the BHs in accordance with the observed relations for a very wide range of merger progenitors.

A calibration of the relation between the abundance of close galaxy pairs and the rate of galaxy mergers

Estimates of galaxy merger rates based on counts of close pairs typically assume that most of the observed systems will merge within a few hundred Myr (for projected pair separations ≤25 h−1kpc). Here we investigate these assumptions using virtual galaxy catalogues derived from the Millennium Simulation, a very large N-body simulation of structure formation in the concordance Λ cold dark matter (ΛCDM) cosmology. These catalogues have been shown to be at least roughly consistent with a wide range of properties of the observed galaxy population at both low and high redshift. Here we show that they also predict close pair abundances at low redshift which agree with those observed. They thus embed a realistic and realistically evolving galaxy population within the standard structure formation paradigm, and so are well suited to calibrate the relation between close galaxy pairs and mergers. We show that observational methods, when applied to our mock galaxy surveys, do indeed identify pairs which are physically close and due to merge. The sample-averaged merging time depends only weakly on the stellar mass and redshift of the pair. At z≤ 2 this time-scale is T≈T0r25M−0.3*, where r25 is the maximum projected separation of the pair sample in units of 25 h−1kpc, M* is the typical stellar mass of the pairs in units of 3 × 1010h−1M⊙ and the coefficient T0 is 1.1 Gyr for samples selected to have line-of-sight velocity difference smaller than 300 km s−1 and 1.6 Gyr for samples where this velocity difference is effectively unconstrained. These time-scales increase slightly with redshift and are longer than assumed in most observational studies, implying that merger rates have typically been overestimated.

Merged series of normalized water leaving radiances obtained from multiple satellite missions for the Mediterranean Sea

Merging time series of ocean color-derived products provided by independent satellite missions supports related biogeochemical and environmental applications by combining temporally overlapping data sets and by increasing data coverage. The creation of a merged series of normalized water leaving radiances L WN , the primary ocean color product, is presented for the Mediterranean Sea using the SeaWiFS and MODIS data records. The merging relies on an optically-based technique that combines the available L WN signal in a spectrally consistent way. Validation statistics indicate uncertainties associated with the merged L WN decreasing from 23% at 412 nm to 12% in the 500- to 555-nm spectral range. The inter-comparison of the sensor-specific products, conducted at the scale of the basin for daily-to-monthly time scales, indicates an overall consistency. The level of differences varies with the wavelength considered and shows a marked seasonal cycle, with differences that tend to be higher in winter. The merged series is remarkably consistent with the sensor-specific data, with average absolute percent differences lower than 10% for all wavelengths below 555 nm. The benefit of merging in terms of sampling frequency over the basin is also illustrated. A merged series of L WN data based on the two considered missions provides valid data over 36% of the basin area on a daily basis.

Numerical models of Saturn's long-lived anticyclones

New measurements of the dynamical properties of the long-lived Saturn's anticyclonic vortex known as “Brown Spot” (BS), discovered during the Voyager 1 and 2 flybys in 1980–1981 at latitude 43.1° N, and model simulations using the EPIC code, have allowed us to constrain the vertical wind shear and static stability in Saturn's atmosphere (vertically from pressure levels from 10 mbar to 10 bars) at this latitude. BS dynamical parameters from Voyager images include its size as derived from cloud albedo gradient (6100 km East–West times 4300 km North–South), mean tangential velocity ( 45 ± 11 m s −1 at 2400 km from center) and mean vorticity ( 4.0 ± 1.5 × 10 −5 s −1 ) , lifetime >1 year, drift velocity ( 5.3 ± 0.1 m s −1 ) relative to Voyager's System III rotation rate, mean meridional atmospheric wind profile at cloud level at its latitude and interactions with nearby vortices (pair orbiting and merging). An extensive set of numerical experiments have been performed to try to reproduce this single vortex properties and its observed mergers with smaller anticyclones by varying the vertical structure of the zonal wind and adjusting the static stability of the lower stratosphere and upper troposphere. Within the context of the EPIC model atmosphere, our simulations indicate that BS's drift velocity, longevity and merging behavior are very sensitive to these two atmospheric properties. The best results at the BS latitude occur for static stability conditions that use a Brunt–Väisäla frequency constant in the upper troposphere (from 0.5 to 10 bar) above 3.2 × 10 −3 s −1 and suggest that the wind speed slightly decays below the visible cloud deck from ∼0.5 to 10 bar at a rate ∂ u / ∂ z ∼ 2 – 6 m s −1 per scale height. Changing the vortex latitude within the band domain introduces latitude oscillations in the vortex but not a significant meridional migration. Simulated mergers always showed orbiting movements with a typical merging time of about three days, very close to the time-span observed in the interaction of real vortices. Although these results are not unique in view of the unknowns of Saturn's deep atmosphere, they serve to constrain realistically its structure for ongoing Cassini observations.

Development and validation of a technique for merging satellite derived aerosol optical depth from SeaWiFS and MODIS

Merging time series of satellite derived aerosol products from independent missions can support aerosol science by combining in a consistent way temporally overlapping data sets and by increasing data coverage. A merging technique applied to satellite aerosol optical depth τ a is presented and tested with SeaWiFS and MODIS-Aqua data. The technique relies on least squares fitting of the available τ a spectra onto a linear or second-order polynomial relation between log-transformed τ a and wavelengths. First, the sensor specific products are compared with field observations collected by a sun-photometer installed on the Acqua Alta Oceanographic Tower in the northern Adriatic Sea. Mean absolute percentage differences are approximately 21% at 412 and 443 nm, and increase with wavelength, with large overestimates in the red and near-infrared bands. The mean absolute differences are typically 0.04. When inter-compared, the 2 satellite products agree well, with mean absolute percentage differences lower than 20% at all wavelengths and little bias. The results of the comparison of the merger outputs with the field data are well in line with the validation results of the sensor specific products, and are comparable for the various merging procedures. The benefits of merging in terms of data coverage are briefly illustrated for the Mediterranean basin.

Sound installation: Blurring the boundaries of the Eye, the Ear, Space and Time

Sound installation interfaces musical and visual art through time and space. It is a sonic intermedia practice, which blurs the boundaries of the visual and aural and includes the spatial, the temporal and the haptic. Since 1977 I have been designing sound installations that merge the senses, offering unique experiences for the listener as participating auditor. In the discussion of several of these works the conceptual considerations in the design of cross-disciplinary works are addressed. These include the parameters derived from the disciplines of sculpture, sound, temporal composition, spatial architecture and audience interactivity. Some works merge many interdisciplinary elements such as sculptural forms, video, photography, radio and performance as well as sound, while others may appear almost invisible. The degree of musical composition and sound design features vary from work to work. Sound installations are rarely static, having many possible outcomes and many works have a high degree of immersive and interactive characteristics. As such they are difficult to document. This article will look at representative examples of my sound installations since 1977 showing diverse approaches to sound installation. It is a potent artform, which has stretched the boundaries of the disciplines of fine art and music, merging sound, time and space in new ways.

The luminosity and redshift distributions of short-duration GRBs

Using the BATSE peak flux distribution we rederive the short GRBs luminosity function and compare it with the observed redshift distribution of long bursts. We show that both distributions are compatible with the assumption that short as well as long bursts follow the star formation rate. In this case the difference between the two observed distributions can be interpreted as arising mostly from differences in the detector's sensitivity to long and short bursts, while the local rate of short bursts is 0.1 h 3 70 Gpc -3 yr -1 . We also consider the possibility that short GRBs may be associated with binary neutron star mergers and estimate the effect of the merging time delay on the luminosity function and redshift distribution. We find that in this case the local rate of short GRBs is ∼0.8 h 3 70 Gpc -3 yr -1 . Assuming that all binary merging systems lead to short GRBs, we find a typical jet opening angle of 1.6°.

Merging time zones: promoting international communication through videoconferencing

Nursing is viewed increasingly from an international perspective. Communication between nurses from different countries and cultures is becoming an important feature of nurses’ education as well as their professional lives. While it is often not possible for nurse educators and students to visit their counterparts in other countries, it is possible for them to engage in personal contact and discussion through videoconferencing technology. An exploratory international videoconferencing case-study project, which was undertaken to enable educators to further their knowledge of videoconferencing as a teaching method, and enable students to meet in a videoconference class and discuss common issues in nursing education and practice with their counterparts in another country is presented. Two groups of registered nurse students, one undergraduate and one graduate, from the Department of Nursing, University of Scranton, Pennsylvania, USA and the School of Nursing and Midwifery, University College Dublin, Ireland were brought together for one class each. This article presents these case studies in the context of videoconferencing in higher education, describes the practical and pedagogical considerations in implementation and makes recommendations for further use of videoconferencing to foster communication and help students in different countries to develop greater international awareness of nursing practice and health care.

Properties of cluster satellites in hydrodynamical simulations

We analyse the dynamical and thermal evolution of dark matter and the intracluster medium in hydrodynamical N-body simulations of galaxy clusters. Starting from a sample of 17 high-resolution objects, with virial mass ranging from 3 × 1014 to 1.7 × 1015h−1 M⊙, we follow the build-up of the systems in dark matter and hot gas through the repeated merging of satellites along their merging history trees. We measure the self-bound mass fraction of subhaloes as a function of time after the merging, estimate the satellite mean orbital properties as a function of the mass ratio with the main cluster at merging time, and study the evolution of their internal velocity dispersion, gas temperature and entropy as the substructure is disrupted by various dynamical processes, eventually reaching thermodynamic equilibrium in the gravitational potential of the main cluster. We model some relevant properties of subhalo orbits, as the time of the first pericentric and apocentric passages, and the typical distances and velocities at the corresponding times. This survival study can be used to interpret the dynamics of observed merging clusters; as an example, we apply our results to the system 1E0657-56. We show that, in the light of our results, the most likely interpretation of the data for this cluster points to the merger of a small group with mass M≈ 1 × 1013h−1 M⊙ with a massive cluster with M≈ 1.3 × 1015h−1 M⊙.

Time Scales and Tidal Effects in Minor Mergers

We use controlled N-body simulation to investigate the dynamical pro- cesses (dynamical friction, tidal truncation, etc.) involved in the merging of small satellites into bigger halos. We confirm the validity of some analytic formulae pro- posed earlier based on simple arguments. For rigid satellites represented by softened point masses, the merging time scale depends on both the orbital shape and con- centration of the satellite. The dependence on orbital ellipticity is roughly a power law, as suggested by Lacey & Cole, and the dependence on satellite concentration is similar to that proposed by White. When merging satellites are represented by non-rigid objects, Tidal eects must be considered. We found that material beyond the tidal radius are stripped o. The decrease in the satellite mass might mean an increase in the merging time scale, but in fact, the merging time is decreased, because the stripped-o material carries away a proportionately larger amount of of orbital energy and angular momentum.

Abundances for metal-poor stars with accurate parallaxes

Abundances for elements and Fe in about 150 field subdwarfs and early subgiants with accurate parallaxes and kinematic data are used to discuss the run of abundance ratios in metal-poor stars in the solar neighborhood. Based on kinematics, we separated stars into two populations: the first one has a positive velocity of rotation around the galactic center, and it is likely to be related to the dissipational collapse of the galaxy; the second one has either negligible or negative rotational velocity, and it is likely related to an accretion component. The two populations show a large overlap in metallicity. However, they show distinct chemical properties. For the first population we found that there are close correlations (with small scatters around) of the rotational velocity with metallicity and with the Fe/α abundance ratio: this might be a signature of a not very fast collapse of the progenitor clouds, with enough time for a significant contribution by SNe Ia, although this result needs to be confirmed by a 3-D/non-LTE study. On the other side, the second population exhibits a larger scatter in both the above mentioned relations, and on average, a larger Fe/α ratio at a given metallicity, suggesting a larger scatter in ages. We argue that the lack of stars with moderate rotational velocities and high Fe/α abundance ratios is due to the short merging time for protogalactic clouds with prograde motion, while the presence of a group of counter-rotating stars with this characteristics indicates a much longer typical lifetimes for protogalactic fragments having such a motion. Finally, we found that perigalactic distances correlate with the Fe/α abundance ratios better than the apogalactic distances.

Spurious trends in satellite MSU temperatures from merging different satellite records

Analysis of global surface air temperature records has indicated that recent years have been among the warmest since the late nineteenth century1, with 1995 being the warmest year on record2. But the rate of global annual mean surface warming of 0.13 °C per decade during the period 1979–95 differs substantially from the global lower-tropospheric cooling trend of – 0.05 °C per decade3 Inferred from the record (MSU-2R) of radiance measurements by the satellite Microwave Sounder Unit (MSU)4,5. Accordingly, the satellite record has been widely cited by sceptics as evidence against global warming6–10. However, a substantial fraction of the measured radiance originates not from the atmosphere but from the Earth's surface11, and gives rise to high noise levels. This noise can lead to errors when merging temperature time series obtained from different satellites. Here we present comparisons among different MSU retrievals, sea surface temperatures (SSTs), and equivalent MSU temperatures derived from an atmospheric general circulation model forced with observed SSTs. The comparisons, focused on the tropics where atmospheric temperatures are closely tied to SSTs, strongly suggest that two spurious downward jumps occur in the MSU-2R record coinciding with changes in satellites, and that the real trend in MSU temperatures is likely to be positive, albeit small.