937 resultados para Quality of Data


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Many next-generation distributed applications, such as grid computing, require a single source to communicate with a group of destinations. Traditionally, such applications are implemented using multicast communication. A typical multicast session requires creating the shortest-path tree to a fixed number of destinations. The fundamental issue in multicasting data to a fixed set of destinations is receiver blocking. If one of the destinations is not reachable, the entire multicast request (say, grid task request) may fail. Manycasting is a generalized variation of multicasting that provides the freedom to choose the best subset of destinations from a larger set of candidate destinations. We propose an impairment-aware algorithm to provide manycasting service in the optical layer, specifically OBS. We compare the performance of our proposed manycasting algorithm with traditional multicasting and multicast with over provisioning. Our results show a significant improvement in the blocking probability by implementing optical-layer manycasting.

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Electron Diffraction Structure Analysis (EDSA) with data from standard selected-area electron diffraction (SAED) is still the method of choice for structure determination of nano-sized single crystals. The recently determined heavy atom structure α-Ti2Se (Albe & Weirich, 2003) is used as an example to illustrate the developed procedure for structure determination from two-dimensionally SAED data via direct methods and kinematical least-squares refinement. Despite the investigated crystallite had a relatively large effective thickness of about 230 Å as determined from dynamical calculations, the obtained structural model from SAED data was found in good agreement with the result from an earlier single crystal X-ray study (Weirich, Pöttgen & Simon, 1996). Arguments, which support the validity of the used quasi-kinematical approach, are given in the text. The influences of dynamical and secondary scattering on the quality of the data and the structure solution are discussed. Moreover, the usefulness of first-principles calculations for verifying the results from EDSA is demonstrated by two examples, whereas one of the structures was unattainable by conventional X-ray diffraction.

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Because of frequent topology changes and node failures, providing quality of service routing in mobile ad hoc networks becomes a very critical issue. The quality of service can be provided by routing the data along multiple paths. Such selection of multiple paths helps to improve reliability and load balancing, reduce delay introduced due to route rediscovery in presence of path failures. There are basically two issues in such a multipath routing Firstly, the sender node needs to obtain the exact topology information. Since the nodes are continuously roaming, obtaining the exact topology information is a tough task. Here, we propose an algorithm which constructs highly accurate network topology with minimum overhead. The second issue is that the paths in the path set should offer best reliability and network throughput. This is achieved in two ways 1) by choice of a proper metric which is a function of residual power, traffic load on the node and in the surrounding medium 2) by allowing the reliable links to be shared between different paths.

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Femtocells are a new concept which improves the coverage and capacity of a cellular system. We consider the problem of channel allocation and power control to different users within a Femtocell. Knowing the channels available, the channel states and the rate requirements of different users the Femtocell base station (FBS), allocates the channels to different users to satisfy their requirements. Also, the Femtocell should use minimal power so as to cause least interference to its neighboring Femtocells and outside users. We develop efficient, low complexity algorithms which can be used online by the Femtocell. The users may want to transmit data or voice. We compare our algorithms with the optimal solutions.

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We consider optimal power allocation policies for a single server, multiuser system. The power is consumed in transmission of data only. The transmission channel may experience multipath fading. We obtain very efficient, low computational complexity algorithms which minimize power and ensure stability of the data queues. We also obtain policies when the users may have mean delay constraints. If the power required is a linear function of rate then we exploit linearity and obtain linear programs with low complexity.

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Streamflow forecasts at daily time scale are necessary for effective management of water resources systems. Typical applications include flood control, water quality management, water supply to multiple stakeholders, hydropower and irrigation systems. Conventionally physically based conceptual models and data-driven models are used for forecasting streamflows. Conceptual models require detailed understanding of physical processes governing the system being modeled. Major constraints in developing effective conceptual models are sparse hydrometric gauge network and short historical records that limit our understanding of physical processes. On the other hand, data-driven models rely solely on previous hydrological and meteorological data without directly taking into account the underlying physical processes. Among various data driven models Auto Regressive Integrated Moving Average (ARIMA), Artificial Neural Networks (ANNs) are most widely used techniques. The present study assesses performance of ARIMA and ANNs methods in arriving at one-to seven-day ahead forecast of daily streamflows at Basantpur streamgauge site that is situated at upstream of Hirakud Dam in Mahanadi river basin, India. The ANNs considered include Feed-Forward back propagation Neural Network (FFNN) and Radial Basis Neural Network (RBNN). Daily streamflow forecasts at Basantpur site find use in management of water from Hirakud reservoir. (C) 2015 The Authors. Published by Elsevier B.V.

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This report amplifies and refines some of the data already issued covering the water resources of Volusia County, which were published as Report of Investigations No. 21. The work in the report was accomplished as a cooperative program between the Department of Natural Resources, the U. S. Geological Survey and the Board of County Commissioners of Volusia County. Volusia County is almost totally dependent upon the water which falls upon the county and has a recharge area contained along the western portion and the central portions of the county. Excellent water is produced in the areal recharge and it is anticipated that this data will expand the existing knowledge of the water resources to permit the development of a great capacity for existing utilities and to offset and solve some of the problems now in the area. (PDF has 71 pages.)

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The influences of age, size, and condition of spawning females on fecundity and oocyte quality were analyzed for the Patagonian stock of Argentine Hake (Merluccius hubbsi). Samples of mature females were collected in the spawning area as part of 2 research surveys conducted in January 2010 and 2011, during the peak of the reproductive season. Batch fecundity (BF) ranged between 40,500 (29 cm total length [TL]) and 2,550,000 (95 cm TL) hydrated oocytes, and was positively correlated with TL, gutted weight, age, hepatosomatic index (HSI), and the relative condition factor (Kn). Relative fecundity ranged between 85 and 1040 hydrated oocytes g–1 and showed significant positive relationships with gutted weight, HSI, and Kn; however, coefficients of determination were low for all regressions. Dry weights of samples of 100 hydrated oocytes ranged between 1.8 and 3.95 mg and were positively correlated with all variables analyzed, including batch and relative fecundity. Multiple regression models created with data of the morphophysiological characteristics of females supported maternal influences on fecundity and egg weights. Within the studied size range (29–95 cm TL), larger individuals had better somatic and egg condition, mainly revealed by higher HSI and hydrated oocytes with larger oil droplets (275.71μm [standard error 1.49]). These results were associated with the higher feeding activity of larger females during the spawning season in comparison with the feeding activity of young individuals (<5 years old); the better nutritional state of larger females, assumed to result from more feeding, was conducive to greater production of high-quality eggs.

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The present paper deals with the physico-chemical data of 13 rainfed and drainable dry bundhs of Bhilwara District (India). All the dry bundhs studied showed a slightly alkaline pH ranging from 7.5 to 8.5. Electrical conductivity ranged from 2 to 8 millimhos/cm. Organic carbon in sediment fluctuated from 0.30 to 0.75%. Nitrogen, phosphate and potassium levels were fairly good, at 30 to 50 and 24 to 36 mg/100 g of soil respectively. Based on these data it was inferred that these dry bundhs were highly productive and suitable for freshwater fish culture.

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The paper presents the results of a bacteriological survey carried out on 2,917 samples of frozen prawn, 55 samples of raw material, 35 samples of water, 4 samples of ice and 42 samples of various equipment used for processing. The survey covered a period of three years (1960-63) and comprised of samples collected from five of the leading processing factories in Cochin. Frozen products tested consisted of headless (marine and fresh water), peeled and deveined and cooked frozen samples. Statistical analysis of the data shows that there is no significant variation between samples and between factories with respect to product quality. The standard plate count varied between 1.0x10(4 superscript) and 1.0x10(6 superscript) per gram for headless and between 1.0x10(4 superscript) and 1.0x10(7 superscript) for peeled and deveined and cooked frozen samples. Majority of the samples had bacterial load well within the limits prescribed for such products.

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The proximate compositions and amino acid make-up of silver jew fish (Johnius argentatus), Indian halibut (Psettodes erumei), grey mullet (Mugil cephalus) and pearl spot (Etroplus suratensis) are reported. Calorific values of these fishes have been calculated from their proximate compositions and their amino acid make-up compared with the available data for beef and egg. From the study, pearl spot is adjudged to be the most nutritive among the fishes studied, followed by Indian halibut, grey mullet and silver jew fish.

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Data on proximate composition, total volatile bases, total non-protein nitrogen and bacterial quality of commercial samples of Indian fish meal are presented in this communication. The samples vary very much in quality depending on the type of raw material used and method of processing followed. The data are discussed in relation to the Indian standard Specifications for fish meal as livestock feed.

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The Dependency Structure Matrix (DSM) has proved to be a useful tool for system structure elicitation and analysis. However, as with any modelling approach, the insights gained from analysis are limited by the quality and correctness of input information. This paper explores how the quality of data in a DSM can be enhanced by elicitation methods which include comparison of information acquired from different perspectives and levels of abstraction. The approach is based on comparison of dependencies according to their structural importance. It is illustrated through two case studies: creation of a DSM showing the spatial connections between elements in a product, and a DSM capturing information flows in an organisation. We conclude that considering structural criteria can lead to improved data quality in DSM models, although further research is required to fully explore the benefits and limitations of our proposed approach.

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A self-organizing map (SOM) was used to cluster the water quality data of Xiangxi River in the Three Gorges Reservoir region. The results showed that 81 sampling sites could be divided into several groups representing different land use types. The forest dominated region had low concentrations of most nutrient variables except COD, whereas the agricultural region had high concentrations of NO3N, TN, Alkalinity, and Hardness. The sites downstream of an urban area were high in NH3N, NO2N, PO4P and TP. Redundancy analysis was used to identify the individual effects of topography and land use on river water quality. The results revealed that the watershed factors accounted for 61.7% variations of water quality in the Xiangxi River. Specifically, topographical characteristics explained 26.0% variations of water quality, land use explained 10.2%, and topography and land use together explained 25.5%. More than 50% of the variation in most water quality variables was explained by watershed characteristics. However, water quality variables which are strongly influenced by urban and industrial point source pollution (NH3N, NO2N, PO4P and TP) were not as well correlated with watershed characteristics.

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In the present study, the quality of post-thaw sperm of red seabream Pagrus major frozen with 6-24% DMSO was investigated. The motility, average path velocity and fertilizing capacity of fresh and their corresponding post-thaw sperm were examined for evaluation of the post-thaw sperm motion characteristics and its association with fertilizing capacity. An analysis of sperm motility before and after cryopreservation has been performed using computer-assisted sperm analysis (CASA). For post-thaw sperm frozen with 12-21% DMSO, the percentages of motile sperm were not significantly (P > 0.05) changed 10 s after activation. Moreover, the main motility pattern and swimming velocity of the motile post-thaw sperm were not significantly (P > 0.05) changed and the progressive linear motion was still the dominant pattern. However, the total motility of post-thaw sperm (72.3 +/- 6.3%) 30 s after activation was (P < 0.05) lower than the corresponding fresh sperm (82.7 +/- 7.2%). Additionally, the fertilizing capacity of post-thaw sperm was investigated with a standardized sperm to egg ratio 500:1. There is a linear regression relationship between the percentage of motile post-thaw sperm and fertilizing capability. These data demonstrate that 12-21% DMSO can provide good protection to the sperm during the freezing-thawing process. (c) 2006 Elsevier B.V. All rights reserved.