Top PDF Active-Distributed Temperature Sensing to continuously quantify vertical flow in boreholes

Active-Distributed Temperature Sensing to continuously quantify vertical flow in boreholes

Active-Distributed Temperature Sensing to continuously quantify vertical flow in boreholes

4. Field Methods We constructed the prototype A-DTS flowmeter from a single 295 m length of BruSens FO cable. Of this, 78 m could be heated by connecting this electrically isolated section to a power supply. During the experi- ments, the heated cable was powered by 220 and 233 ACV, giving power intensities along the cable of 18.8 and 21.8 W m 21 , respectively. An equal length of unheated cable, obtained by bending the cable back on itself after the latter electrical connection, was held at a uniform distance away of 3.5 cm using cable ties every 2 m (Figure 1b). From DTS temperature measurements along these two parallel lengths of heated and unheated cable, the heating effect DT can be obtained. A power supply cable and a steel cable to sup- port the weight of the system were also fixed relative to the central heated cable using cable ties. These cable tie centralizers also helped to ensure that the heated cable remained away from the borehole wall. The flowmeter was then installed in B2 to monitor the borehole vertical flow at all depths simultaneously. For the DTS calibration, additional lengths of unheated cable at the surface were placed in ambient (water kept mixed with an air pump) and a cold calibration bath (water wetted ice in an insulated box). Because the tool was constructed from a single length of cable containing two fibers, spliced together at the far end, the resulting duplexed DTS data set contained four reference sections. In each bath a Tinytag logger (Gem- ini Data Loggers, UK), independently recorded the temperature. The Stokes and anti-Stokes backscatter intensities were obtained every 12.5 cm along the cable using a Silixa Ultima instrument with 5 km range. The instrument integrated the backscatter over times ranging from 1 to 10 s. The data were subsequently postprocessed to derive the temperature using the Stokes and anti-Stokes intensities from three of the ref- erence sections and the single-ended algorithm outlined in Hausner et al. [2011].
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Capabilities, limitations and new horizons of Fibreoptic Distributed Temperature Sensing in. ecohydrological and hydrogeological research

Capabilities, limitations and new horizons of Fibreoptic Distributed Temperature Sensing in. ecohydrological and hydrogeological research

Thank You INTERFACES - Ecohydrological interfaces as critical hotspots for transformations of ecosystem exchange fluxes and biogeochemical cycling. FP7-PEOPLE-2013-ITN, 2013-2017 Large woody debris -A river restoration panacea for stream- bed nitrate attenuation? NERC-NE/L004437/1, 2014-1017 Groundwater flooding: GW-community recovery following an extreme recharge event. NERC-NE/M005151/1, 2014-2015 Active Distributed Temperature Sensing for high-resolution fluid-flow monitoring in boreholes. NE/L012715/1, 2014-2015 Smart tracers and distributed sensor networks for quantifying the metabolic activity in streambed reactivity hotspots NERC- NE/I016120/1, 2011-2013
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Temperature log simulations in high-enthalpy boreholes

Temperature log simulations in high-enthalpy boreholes

Another important application of temperature logs is the identification of fluid loss or feed zones from temperature data obtained under hydraulic testing conditions (Okandan 2012; Steingrimsson 2013). Examples of using temperature measurements in boreholes are multifold. Pehme et  al. (2010) identified hydraulically active fractures in dolomite and sandstone aquifers; Klepikova et  al. (2011) estimated local transmissivities and hydraulic head differences; Nian et al. (2015) predicted flow rates in oil and gas produc- tion wells. These authors stressed the satisfactory accuracy of temperature-derived flow velocities compared to direct flow measurement. In recent years, fiber-optic distributed temperate sensing (DTS), which is a robust means of acquiring continuous temperature profiles instantaneously along the length of the cable (Großwig et al. 1996), has also been extensively used to improve the accuracy of flow rate profiling and the detection of frac- ture zones (Read et al. 2013; Coleman et al. 2015; Read et al. 2015; Bense et al. 2016).
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Applications of Distributed

Temperature Sensing in Subsurface

Hydrology

Applications of Distributed Temperature Sensing in Subsurface Hydrology

The measurement of the vertical flow in wells can improve our conceptual understanding of subsurface fluid movement, which can aid in, for example, groundwater resources man- agement or geothermal resource assessments. In open or long-screened wells penetrating multiple permeable units or fractures, vertical flow typically occurs in hydraulically un- stressed conditions due to the natural occurrence of a vertical head gradient. Flow logs obtained in unstressed conditions gives a qualitative guide to fracture inflow and outflow zones (Hess, 1986). Alternatively, flow logs obtained in a pumping well at multiple dif- ferent pumping rates allow the depth variability of transmissivity to be estimated (Paillet et al., 1987). Flow logs in observation wells affected by nearby pumping enables the con- nectivity of fractures to be determined (Paillet, 1998; Klepikova et al., 2013). In all cases, the in-well flow is not directly indicative of flow in the formation itself since the presence of the well as a high permeability vertical conduit allows the short circuiting of flow. In addition, flow logs have inherent value for geochemical sampling campaigns. Ambient vertical flow through the well may redistribute contaminants and mean that passive sam- pling approaches do not reproduce the same depth variability as present in the aquifer itself (Elci et al., 2003). Typical flow logging techniques involve lowering an impeller or electromagnetic flowmeter down a well and either measuring continuously (trolling) or at multiple points with the probe held stationary. At low flows a heat pulse flowmeter may be used at fixed depths (Paillet, 1998).
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FIBER-OPTIC DISTRIBUTED TEMPERATURE SENSING OF LARGE HOT WATER STORAGE TANKS

FIBER-OPTIC DISTRIBUTED TEMPERATURE SENSING OF LARGE HOT WATER STORAGE TANKS

Fiber-optic DTS versus PT100 temperature sensors Fig. 5 shows the temperature distribution over the heat storage height determined by the fiber-optic tempera- ture measuring compared to the values measured by the 16 PT100 temperature sensors. The mean of both measurements is identical, which is a direct conse- quence of the offset correction method described above. However, a pronounced correlation between the two measurement methods can be stated at each indi- vidual measuring point as well. The maximum deviation is 0.4 K at 6.7 m above the storage floor. In the upper storage tank area, the temperature readings of the PT100 sensors do not increase strictly monotone with the storage height. This contradicts the natural density stratification, especially since the measurement was carried out during a resting phase of the heat storage. Therefore these fluctuations of the PT100 data can be led back to a measurement uncertainty. The coinci- dence results between the two measurement methods at every position allow concluding that the fiber-optic DTS system is able to resolve the temperature distribu- tion in the storage.
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Technical note: Using distributed temperature sensing for Bowen ratio evaporation measurements

Technical note: Using distributed temperature sensing for Bowen ratio evaporation measurements

soil heat flux (Bense et al., 2016), and wind speed (Sayde et al., 2015). First introduced by Euser et al. (2014), DTS can also be used for measuring the Bowen ratio, to estimate the evaporation flux. A dry and wet stretch of the same fibre optic cable are installed vertically to obtain the so-called dry- and wet-bulb temperature gradient, respectively. This method mitigates some problems of the conventional Bowen ratio, since usually at least two different sensors are used to mea- sure the temperature and vapour pressure gradients, of which each has its own independent error (Angus and Watts, 1984; Fuchs and Tanner, 1970). The DTS-based Bowen ratio does not suffer from this drawback, by having a large amount of data points over the height (up to 8 per metre) with only a single sensor. It also has a resolution of 0.06 K for 1 min av- erages (Silixa machine calibration), and will be more accu- rate when measuring over a longer time period, allowing for very small temperature gradients to be measured.
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Autonomous distributed temperature sensing for long-term heated applications in remote areas

Autonomous distributed temperature sensing for long-term heated applications in remote areas

In summary we see that heat delivery, per meter, increases with the square of applied voltage, and decreases with the square of cable length (since total power delivered increases linearly, as does the number of meters over which that energy is divided). Thus short fiber-optic cables with a copper armor can be heated at low voltage, and long cables with a stainless steel armor require high voltage. Tests at the River Thur in Switzerland have shown that a 1500 m copper strand with a total cross-section of 0.85 mm 2 wrapped around a 250 m long fiber-optic cable reached a maximum change in temperature of around 2 Kelvin (K) in flowing water with a temperature of 15.5 to 18.0 ◦ C when heated for 15 min at 230 V. How- ever, this degree of heating would differ according to the di- ameter of the fiber-optic cable and the thermal heat capacity of the cable and surrounding material, and if flowing water was present. Hence, pre-tests regarding the heating behavior must be performed prior to the field installation to evaluate the heating behavior in the surrounding medium, e.g. water, soil, gravel, etc. In general, the fiber-optic cable should not be kept in loops or on cable drums during heated applications, as this might cause overheating of the metal armor of the ca- ble, leading to cable damage and potentially cable fires. In order to evade this risk only small sections of the fiber-optic cable may be heated. This would exclude sections particu- larly vulnerable to heating, such as cable sections kept on a cable drum or in tight loops. For safety reasons, an au- tonomous DTS system should have an alarm that automat- ically switches off the power, and thereby stops heating of the fiber-optic cable, when temperatures reach a critical level, e.g. the 85 ◦ C which outdoor cables typically resist whilst in continuous operation.
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Quantifying thermal refugia connectivity by combining  temperature modeling, distributed temperature  sensing, and thermal infrared imaging

Quantifying thermal refugia connectivity by combining temperature modeling, distributed temperature sensing, and thermal infrared imaging

DTS units measure temperatures by sending a laser pulse down a fiber-optic cable and timing the return signal. Al- though most of the reflected energy has its original wave- length, a portion of the energy is absorbed and re-emitted at both shorter (anti-Stokes backscatter) and longer (Stokes backscatter) wavelengths. Temperatures along the cable are determined from the Stokes / anti-Stokes ratio (Selker et al., 2006). A 1 km silver armored DTS cable was deployed to measure diurnal stream temperatures in the main stem and East Walker rivers. Data were collected over 400 m in the East Walker River at Rafter 7 Ranch on 18–23 June 2015 and over 450 m in the main stem Walker River at Stanley Ranch on 25–30 June 2015 (Fig. 1). The year 2015 was dry and the snowpack was at 5 % of normal levels. The DTS ca- ble was deployed in a U shape at both sites, with approxi- mately 400 m of cable on each side of the stream to capture lateral stream temperature differences. The cable was sus- pended in the water column approximately 10 cm above the streambed with steel stakes and leashes. Main stem Walker River DTS deployment included approximately 20 m of a flood irrigation return flow canal named the Wabuska Drain. The Wabuska Drain was not flowing during the drought when the DTS was deployed but contained standing water and was connected on the surface with the Walker River.
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SORET AND DUFOUR EFFECTS ON STEADY MHD CONVECTIVE FLOW PAST A CONTINUOUSLY MOVING POROUS VERTICAL PLATE DIPAK SARMA

SORET AND DUFOUR EFFECTS ON STEADY MHD CONVECTIVE FLOW PAST A CONTINUOUSLY MOVING POROUS VERTICAL PLATE DIPAK SARMA

A steady two dimensional MHD convective flow of an incompressible viscous and electrically conducting fluid past a continuously moving porous vertical plate with Soret and Dufour effects is analyzed. A magnetic field of uniform strength is assumed to be applied transversely to the direction of the main flow. The solutions for the velocity field, temperature and concentrations are performed for a wide range of the governing flow parameters viz the Soret number, Prandtl number, Schmidt number, Grashof number for heat transfer, Dufour number, Solutal Grashof number and Hartmann number. The effects of these flow parameters on the velocity, temperature, concentration, skin friction coefficient and Sherwood number are discussed graphically.
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Active heat pulse sensing of 3 D flow fields in streambeds

Active heat pulse sensing of 3 D flow fields in streambeds

The rigidity and robustness of the Hot Rod and use of heating elements at three different vertical positions provided a method to examine how the flux and its direction varied vertically with depth beneath the streambed interface at indi- vidual locations in a range of different environmental settings and sediment types. The use of two horizontal spacings be- tween the heating elements and thermistors as well as addi- tional thermistors at multiple angles to the heating elements increased confidence in the measurement of heat transport processes and tightened the optimisation routine of the tem- perature data. The addition of the measured input of energy at the heating element in the heat transport equation as a se- ries of discrete heat pulses over the injection period provided one less unknown variable to calibrate against. In many of the experiments conducted in the sand tank and at the ex- perimental site, the optimisation routine using the DREAM algorithm showed that the most likely flux direction from the heat injection depth was not towards the sensor that showed the maximum temperature breakthrough because it uses all of the sensor temperature breakthrough curves in the analysis. The 3-D time series plot was a valuable tool in assessing this result and it also showed whether heat transport was domi- nated by diffusion and/or conduction with radial symmetry around the heating element or whether there was convective heat flow. This interrogation process was found to be critical in the data assessment to ensure that the model did not over- fit the measured data with unrealistic physical values for the sediment and heat transport conditions.
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Investigating patterns and controls of groundwater up welling in a lowland river by combining Fibre optic Distributed Temperature Sensing with observations of vertical hydraulic gradients

Investigating patterns and controls of groundwater up welling in a lowland river by combining Fibre optic Distributed Temperature Sensing with observations of vertical hydraulic gradients

Although streambed VHG patterns identified in this study were not suitable for directly determining groundwater– surface water exchange fluxes, when combined with FO- DTS observations of streambed temperature anomalies, they proved a useful indicator for the discrimination of driv- ing forces and inhibitors of exchange over the aquifer–river interface. The comparison of patterns in VHG and FO- DTS monitored temperature anomalies provides a powerful framework for the identification of aquifer–river exchange flow in dependence of streambed hydraulic conductivity pat- terns. Our results illustrate the value of combining observa- tions of VHG and FO-DTS sampled temperature patterns for improving the understanding of drivers and controls of groundwater–surface water exchange in lowland rivers with complex small-scale patterns in streambed transmissivity. By using comparative FO-DTS and VHG observations as a hy- potheses testing tool, this study furthermore provides a suc- cessfully validated strategy for the optimisation of experi- mental design in lowland river streambeds with limited in- formation on streambed structure and physical properties.
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Monitoring temporal patterns of vertical hyporheic flux via distributed temperature sensors

Monitoring temporal patterns of vertical hyporheic flux via distributed temperature sensors

Abstract Hyporheic exchange is of great significance for evaluating and developing water resources, as well as protecting ecosystem health. Temperature monitoring is one of the powerful tools for recognizing the hyporheic flux with high precision, low cost and great convenience. The streambed temperature at different depths (0 to 1.00 m), and the air and stream water temperatures at Dawen River, Jining City, were monitored using distributed temperature sensors (DTS). The temperature series were used to estimate the hyporheic flux through the analytical solution of the governing one-dimensional heat transport equation. The temporal patterns of flux along the vertical profile were analysed. The results indicated that surface water and air temperatures fluctuated approximately sinusoidally, and the groundwater temperature was relatively stable over time. The hyporheic flux at different depths showed different temporal patterns. Moreover, the dynamic curves of hyporheic flux were depth-dependent and probably controlled by the stream water level and groundwater field.
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Sensory flow shaped by active sensing: sensorimotor strategies in electric fish

Sensory flow shaped by active sensing: sensorimotor strategies in electric fish

As introduced above, latency-coded sensory input is being transformed through a temporal gating mechanism into rate-based information in the ELL, which is subjected to plastic modulations depending on prior sensory input. Indeed it was shown that the behavioral sensitivity of electric fish to novel stimuli depends on the time-averaged mean of the prior sensory input, so that responses following long periods of stationary input are enhanced (Caputi et al., 2003; Röver et al., 2012). The plastic feedback to the ELL and the formation of anti-Hebbian plasticity (Fig.8) are in agreement with these results. One could expect that the responsiveness in the ELL would be suppressed under perfectly static condition. This is similar to the visual system, where fixation and suppression of eye movements leads to fading (Troxler’s effect). As a result, neurons in the ELL would be highly sensitive to changes in the environment. Alternatively, comparable to the effect of eye movements, small body motions in electric fish may suppress complete adaptation in a static environment (Stamper et al., 2012). The relevant parameters for electric flow analysis are the differences in locally measured EI amplitudes over time. The difference in local EOD amplitude between successive EODs would enable measurement of the temporal slope parameter discussed above. In contrast to the spatial coding based on the somatotopic maps of the ELL, temporal coding is not dependent on a high number of electroreceptors and a moving animal may in principle be able to obtain object information by analysing the reading of a single electroreceptor in time. During va-et-vient behavior, the peak of activity in the ELL would move somatotopically while the animal scans an object. Thus, in order to decipher the sensory input in its temporal pattern, spatially disparate data need to be compared. This is different for a temporal approach in which successive inputs from a single location are compared. The circuitry of the ELL as briefly explained above is
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Magnetohydrodynamic Buoyancy-Driven Flow In Partially Active Vertical Walls Of A Square Cavity

Magnetohydrodynamic Buoyancy-Driven Flow In Partially Active Vertical Walls Of A Square Cavity

Fig. 11 exhibits the average Nusselt number for three different active locations for various Hartmann numbers for Pr = 0.71, Gr = 10 5 and EC=10 -5 . As expected when the Hartmann number increases the average Nusselt number decreases, but the rate of heat transfer is high in the middle–middle active locations and low for bottom-top active locations. The influence of the Hartmann number (Ha) on mid-height and mid-width velocity profiles for top-bottom active location are presented in Fig. 7 and Fig. 8 respectively for Pr = 0.71, Gr = 10 5 and EC=10 -5 . The mid-height velocity profile is enhanced when the Hartmann number is decreases are shown in Fig 7. The U- velocity along the vertical centerline of the enclosure for top-bottom active location with various values of Ha presented in Fig. 8. The variation of velocity is increases along vertically from bottom to top, the velocity variation is noticed more upper of the enclosure but the mid-width velocity decreases with increasing of Hartmann number (Ha). Fig. 9 and Fig. 10 delineate variation of U- velocity profile along the vertical centerline in cavity for Ha=0 and Ha=30 with different active locations, mainly observe U-velocity profile for top- bottom, middle-middle and bottom-top active locations. The velocity increases with the active location moving from top to bottom are shown in Fig. 10. The velocity variation is observed more for bottom-top active location (Fig. 9c) and also low velocity variation is noticed for Ha=0 and Ha=30 for top-bottom active location (Fig. 9c).The magnetic field effect (Ha=30) on horizontal velocity profile, the velocity curve shifted from wave form to linear curve. This change observed clearly near top wall/upper half of the cavity.
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Using Flow Cytometry to Quantify Microbial Heterogeneity

Using Flow Cytometry to Quantify Microbial Heterogeneity

Recently Attfield and colleagues (Attfield et al., 2001) investigated heterogeneity of stress gene expression in Saccharomyces cerevisiae using enhanced green fluorescent protein (EGFP). A sequence of DNA encoding the heat shock and stress elements of the S. cerevisiae HSP104 gene was used to express EGFP. EGFP expression was found to increase two-fold as cells progressed from growth on glucose to growth on ethanol in an aerobic batch culture. Elegantly designed experiments exploiting the sorting capability of flow cytometry were performed to obtain 3 subpopulations according to the level of stress response (EGFP expression). Clones isolated from these subpopulations all showed similar heat shock responses, irrespective of which group they were isolated from. Thus, it was concluded that although the genetic background influences the mean level of gene expression of a population, heterogeneity of gene expression in a clonal population may have a physiological basis.
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Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

Raman scattering fiber optic distributed temperature sens- ing (DTS) has recently proven to be a powerful tool for accurately measuring ambient temperature at high temporal (1 min) and spatial (1 m) resolution over distances of several kilometers (Selker et al., 2006a,b; Tyler et al., 2009; Roth et al.). It is based on the inelastic scattering of photons (Ra- man effect) causing a temperature dependent intensity ratio between the amplitudes of the backscattered Stokes to anti- Stokes signals. Laser pulses travel within an optical fiber and the backscattered light reaches a detector where the in- tensity of the incident signals is evaluated. The exact position on the fiber of a backscattered signal is determined from the time of flight of a light pulse. The spatial resolution of a DTS system is hardware constraint and depends on the laser pulse length and frequency, and the detector analysis speed. The temporal resolution is basically user specified and de- pends on the noise level acceptance. A longer integration time reduces the noise level by means of a longer sampling and averaging period. For a more detailed description of the DTS system, the reader is referred to Selker et al. (2006a) who also give several examples of possible applications of DTS for temperature measurements in different environmen- tal systems. To date, the use of DTS in environmental mon- itoring has been predominantly focused on hydrological ap- plications (e.g. Selker et al., 2006b; Westhoff et al., 2007; Moffett et al., 2008; Tyler et al., 2008; Hoes et al., 2009; Vogt et al., 2010; Roth et al.), although its characteristics also per- fectly meet the requirements for atmospheric sensing.
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Assessment of detection limits of fiber-optic distributed temperature sensing for detection of illicit connections

Assessment of detection limits of fiber-optic distributed temperature sensing for detection of illicit connections

In order to be able to detect temperature gradients in the sewer, three cable positions were tested by placing one fiber-optic cable (Ø 6mm) mounted at the invert (bottom), on the soffit (top) and on the water level (floating), as displayed in red in Figure 3. The top-mounted part is placed directly under the house connections, such that test volumes come in contact with the cable. There are house connections of 5, 8 and 20 meter. These connections make it possible to look at the temperature attenuation in comparison to discharging directly onto the conduit.
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A continuously towed vertical bipole source for marine magnetometric resistivity surveying

A continuously towed vertical bipole source for marine magnetometric resistivity surveying

The source-receiver separation for the towed source method has a range because the source is not vertical; the lo- cation of the source has a range due to the difference in hor- izontal locations between the surface and the bottom elec- trodes of the bipole source. Then, the source-receiver sep- aration for the towed source method can be derived from two end members. The first one is the horizontal distance between the receiver and the surface electrode of the bipole source, and this distance is the same as that in the station- ary source method. The second one is the horizontal dis- tance between the receiver and the bottom electrode of the bipole source. This horizontal distance is calculated from an acoustic measurement of the distance from the fish at- tached to the winch wire at 100 m above the bottom elec- trode to three OBEMs along the survey line. Figure 4 shows the distances between the fish and each OBEM ob- tained from the acoustic measurement over time. 21, 37, and 24 data points were obtained for OBEM1, OBEM2, and OBEM3, respectively; the measurement was made con- tinuously, but some measurements failed. The horizontal distance between the fish and each OBEM was derived by assuming the fish moved along a line with a constant off- set from each OBEM. The offset was composed of two components; one was the difference in depth between the fish and each OBEM, and the other was the horizontal dis- tance perpendicular to the survey line between the fish and
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Flow  Past an  Exponentially  Accelerated  Infinite  Vertical Plate  and  Temperature  with  Variable  Mass  Diffusion

Flow Past an Exponentially Accelerated Infinite Vertical Plate and Temperature with Variable Mass Diffusion

Mixed heat and mass transfer plays vital roles, in nuclear reactors, space craft design, design of chemical processing equipment, pollution of the environment, formation and dispersion of fog and moisture of agricultural fields. Soundalgekar [19] presented an exact solution to the flow of a viscous fluid past an impulsively started infinite isothermal vertical plate. The solution was derived by the Laplace- transform technique and the effects of heating or cooling of the plate on the flow field were discussed Singh and Naveen Kumar [20] studied free convection effects on flow past an exponentially accelerated vertical plate. Gupta et al. [8] studied free convection on flow past an linearly accelerated vertical plate in the presence of viscous dissipative heat using perturbation method. Chamkha [5] studied the effects of heat absorption and thermal radiation on heat transfer in a fluid particle flow past a surface in the presence of a gravity field. Muthucumaraswamy and Valliamal [16] considered first order chemical reaction on exponentially accelerated isothermal vertical plate with mass diffusion, the dimensionless governing equations are solved using laplace-transform technique. Chandrakala [3] considered analytically thermal radiation effects on moving infinite vertical plate with uniform heat flux. Muthucumaraswamy et al. [15] studied the unsteady flow past an accelerated infinite vertical plate with variable temperature and uniform mass diffusion. Basanth Jha
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Efficient Integration of Web Services with Distributed Data Flow and Active Mediation

Efficient Integration of Web Services with Distributed Data Flow and Active Mediation

There are many issues associated with the current service composition frameworks, and two noticeable ones are interface incompatibility and performance. Web services are normally provided as software services managed by independent service providers [6, 31]. They are globally heterogeneous and adhere to a variety of conventions for control and data. Even when standards are promulgated, such as SQL, the precise meaning and scope of the output will not necessarily match the expectations of another service. A prime example of available web services today are information providers, which expose their functionalities through XML, SQL, and report generators, but are not geared to interoperate with other services, as analytical services or predictive simulations [28]. In a typical composed application, all results from one web service have to be shipped to the application site, handled there, and then shipped to the next web service. In most cases, the centralized data-flow approach is inefficient for integrating large-scale software services. This inefficiency is implicit in all common composition protocols, such as CORBA, DCOM, J2EE, SOAP, and Microsoft .NET.
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