WorldWideScience

Sample records for reservoirs exhibiting roc

  1. Introduction to ROC analysis

    International Nuclear Information System (INIS)

    Kelsey, C.A.; Mettler, F.A.

    1988-01-01

    An elementary introduction to ROC analysis illustrates how ROC curves depend on observer threshold levels and discusses the relation between ROC curve parameters and other measures of observer performance including accuracy sensitivity specificity true positive fraction, true negative fraction, false positive fraction and false negative fraction

  2. Exhibition

    CERN Document Server

    Staff Association

    2017-01-01

    A Look of Hope Islam Mahmoud Sweity From 19 to 30 June 2017 CERN Meyrin, Main Building Islam Mahmoud Sweity Islam Mahmoud Sweity was born in 1997 at Beit Awwa, Palestine. She is currently following a course to get an Art diploma of Painting at the college of Fine Arts at An-Najah National University under the supervision of Esmat Al As'aad. Her portraits, landscapes and still life paintings are full of life and shining colours. Charged of emotional empathy they catch the attention of the viewer and are reminding us that life is beautiful and worth living in spite of all difficulties we have to go through. She participated in many exhibitions and has exposed her drawings in 2015 at CERN and in France in the framework of the exhibition "The Origin“, and in 2017 in the Former Yugoslav Republic of Macedonia, Palestina and Jordan. In this exhibition the oil paintings made in the past year will be presented. For more information : staff.association@cern.ch | T&eacu...

  3. Exhibition

    CERN Multimedia

    Staff Association

    2016-01-01

    Encounters Hanne Blitz From February 1st to 12th 2016 CERN Meyrin, Main Building What is our reaction to a first encounter with a tourist attraction? Contemporary Dutch painter Hanne Blitz captures visitors' responses to art and architecture, sweeping vistas and symbolic memorials. Encounters, a series of oil paintings curated specially for this CERN exhibition, depicts tourists visiting cultural highlights around the world. A thought-provoking journey not to be missed, and a tip of the hat to CERN's large Hadron Collider.

  4. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Sintropie Flavio Pellegrini From 13 to 24 March 2017 CERN Meyrin, Main Building Energia imprigionata - Flavio Pellegrini. The exhibition is composed by eleven wood artworks with the expression of movement as theme. The artworks are the result of harmonics math applied to sculpture. The powerful black colour is dominated by the light source, generating reflexes and modulations. The result is a continuous variation of perspective visions. The works generate, at a first approach, an emotion of mystery and incomprehension, only a deeper contemplation lets one discover entangling and mutative details, evidencing the elegance of the lines and letting the meaning emerge. For more information : staff.association@cern.ch | Tél: 022 766 37 38

  5. Latent HIV reservoirs exhibit inherent resistance to elimination by CD8+ T cells.

    Science.gov (United States)

    Huang, Szu-Han; Ren, Yanqin; Thomas, Allison S; Chan, Dora; Mueller, Stefanie; Ward, Adam R; Patel, Shabnum; Bollard, Catherine M; Cruz, Conrad Russell; Karandish, Sara; Truong, Ronald; Macedo, Amanda B; Bosque, Alberto; Kovacs, Colin; Benko, Erika; Piechocka-Trocha, Alicja; Wong, Hing; Jeng, Emily; Nixon, Douglas F; Ho, Ya-Chi; Siliciano, Robert F; Walker, Bruce D; Jones, R Brad

    2018-02-01

    The presence of persistent, latent HIV reservoirs in CD4+ T cells obstructs current efforts to cure infection. The so-called kick-and-kill paradigm proposes to purge these reservoirs by combining latency-reversing agents with immune effectors such as cytotoxic T lymphocytes. Support for this approach is largely based on success in latency models, which do not fully reflect the makeup of latent reservoirs in individuals on long-term antiretroviral therapy (ART). Recent studies have shown that CD8+ T cells have the potential to recognize defective proviruses, which comprise the vast majority of all infected cells, and that the proviral landscape can be shaped over time due to in vivo clonal expansion of infected CD4+ T cells. Here, we have shown that treating CD4+ T cells from ART-treated individuals with combinations of potent latency-reversing agents and autologous CD8+ T cells consistently reduced cell-associated HIV DNA, but failed to deplete replication-competent virus. These CD8+ T cells recognized and potently eliminated CD4+ T cells that were newly infected with autologous reservoir virus, ruling out a role for both immune escape and CD8+ T cell dysfunction. Thus, our results suggest that cells harboring replication-competent HIV possess an inherent resistance to CD8+ T cells that may need to be addressed to cure infection.

  6. Roc curves for continuous data

    CERN Document Server

    Krzanowski, Wojtek J

    2009-01-01

    Since ROC curves have become ubiquitous in many application areas, the various advances have been scattered across disparate articles and texts. ROC Curves for Continuous Data is the first book solely devoted to the subject, bringing together all the relevant material to provide a clear understanding of how to analyze ROC curves.The fundamental theory of ROC curvesThe book first discusses the relationship between the ROC curve and numerous performance measures and then extends the theory into practice by describing how ROC curves are estimated. Further building on the theory, the authors prese

  7. A comparison of ROC inferred from FROC and conventional ROC

    Science.gov (United States)

    McEntee, Mark F.; Littlefair, Stephen; Pietrzyk, Mariusz W.

    2014-03-01

    This study aims to determine whether receiver operating characteristic (ROC) scores inferred from free-response receiver operating characteristic (FROC) were equivalent to conventional ROC scores for the same readers and cases. Forty-five examining radiologists of the American Board of Radiology independently reviewed 47 PA chest radiographs under at least two conditions. Thirty-seven cases had abnormal findings and 10 cases had normal findings. Half the readers were asked to first locate any visualized lung nodules, mark them and assign a level of confidence [the FROC mark-rating pair] and second give an overall to the entire image on the same scale [the ROC score]. The second half of readers gave the ROC rating first followed by the FROC mark-rating pairs. A normal image was represented with number 1 and malignant lesions with numbers 2-5. A jackknife free-response receiver operating characteristic (JAFROC), and inferred ROC (infROC) was calculated from the mark-rating pairs using JAFROC V4.1 software. ROC based on the overall rating of the image calculated using DBM MRMC software, which was also used to compare infROC and ROC AUCs treating the methods as modalities. Pearson's correlations coefficient and linear regression were used to examine their relationship using SPSS, version 21.0; (SPSS, Chicago, IL). The results of this study showed no significant difference between the ROC and Inferred ROC AUCs (p≤0.25). While Pearson's correlation coefficient was 0.7 (p≤0.01). Inter-reader correlation calculated from Obuchowski- Rockette covariance's ranged from 0.43-0.86 while intra-reader agreement was greater than previously reported ranging from 0.68-0.82.

  8. Basic principles of ROC analysis

    International Nuclear Information System (INIS)

    Metz, C.E.

    1978-01-01

    The limitations of diagnostic accuracy as a measure of decision performance require introduction of the concepts of the sensitivity and specificity of a diagnostic test. These measures and the related indices, true positive fraction and false positive fraction, are more meaningful than accuracy, yet do not provide a unique description of diagnostic performance because they depend on the arbitrary selection of a decision threshold. The receiver operating characteristic (ROC) curve is shown to be a simple yet complete empirical description of this decision threshold effect, indicating all possible combinations of the relative frequencies of the various kinds of correct and incorrect decisions. Practical experimental techniques for measuring ROC curves are described, and the issues of case selection and curve-fitting are discussed briefly. Possible generalizations of conventional ROC analysis to account for decision performance in complex diagnostic tasks are indicated. ROC analysis is shown to be related in a direct and natural way to cost/benefit analysis of diagnostic decision making. The concepts of average diagnostic cost and average net benefit are developed and used to identify the optimal compromise among various kinds of diagnostic error. Finally, the way in which ROC analysis can be employed to optimize diagnostic strategies is suggested

  9. RocKeTeria restaurant

    Science.gov (United States)

    2000-01-01

    When StenniSphere at John C. Stennis Space Center in Hancock County, Miss., opened in May 2000, it introduced the RocKeTeria, a new 1960s-style, space-themed restaurant located in the newly expanded visitor center. The restaurant, operated by the owners of Mary's Drive Inn of Biloxi, features an extensive collection of space-related photos from that era, as well as a full menu of home-style cooking.

  10. Accrual of ROCs LECs and REGOs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the findings of a project to identify the technical and administrative difficulties experienced by microgenerators in accessing the benefits of Renewables Obligation Certificates (ROCs), Levy Exemption Certificates (LECs) and Renewable Electricity Guarantees of Origin (REGO). These include cost, administrative complexity and financial risk. Changes allowing bulk processing, meter data provision, sell and buyback contracts, and alignment of ROCs, LECs and REGOs are discussed as well as making the schemes more customer friendly. The background to the project is traced, and an overview of the processes associated with gaining ROCs, LECs and REGOs is presented.

  11. Receiver operator characteristic (ROC) analysis without truth

    International Nuclear Information System (INIS)

    Henkelman, R.M.; Kay, I.; Bronskill, M.J.

    1990-01-01

    Receiver operator characteristic (ROC) analysis, the preferred method of evaluating diagnostic imaging tests, requires an independent assessment of the true state of disease, which can be difficult to obtain and is often of questionable accuracy. A new method of analysis is described which does not require independent truth data and which can be used when several accurate tests are being compared. This method uses correlative information to estimate the underlying model of multivariate normal distributions of disease-positive and disease-negative patients. The method is shown to give results equivalent to conventional ROC analysis in a comparison of computed tomography, radionuclide scintigraphy, and magnetic resonance imaging for liver metastasis. When independent truth is available, the method can be extended to incorporate truth data or to evaluate the consistency of the truth data with the imaging data

  12. ROC analysis of acid demineralized artificial caries

    International Nuclear Information System (INIS)

    Kang, Byung Cheol

    1997-01-01

    This study is designed to determine the artificial incipient proximal caries lesion detectability by dentists on Ektaspeed Plus film using ROC analysis. Sixteen premolars and 30 molars, which have 52 proximal caries-like demineralized lesions using acid-gel technique were added to 20 sound premolars and 30 sound molars to make 24 plaster blocks. Each block with 4 teeth and 6 contacting proximal surfaces was placed in an optical bench to take 12 bitewing radiographs with Ektaspeed Plus film. Thirty-six dentists acted as observers to evaluated the proximal lesions using five rating scales for ROC analysis. They were also asked to determine the presence or absence of the proximal caries. The true status of the proximal caries was established by the consensus of three oral and maxillofacila radiologists. For evaluation of intra-observer agreement, 9 dentist reread the radiographs at an interval of 1 month. The Pearson correlation coefficient for the intra-observer agreement was 0.746 (good agreement). Ten observer's data set were degenerated. The mean area under ROC curve from 26 observers was 0.806 and standard deviation was 0.061. The sensitivity and the specificity of the binary response were 0.17 (SD=0.11) and 0.78 (SD=0.17) respectively. The binary response only reveal a single values of sensitivity and the specificity. The ROC analysis to assess the diagnostic accuracy in caries detection, which producing estimates of sensitivities for all specifities, yield more comprehensive measures of diagnostic performance than single values for sensitivity and specificity.

  13. pROC: an open-source package for R and S+ to analyze and compare ROC curves.

    Science.gov (United States)

    Robin, Xavier; Turck, Natacha; Hainard, Alexandre; Tiberti, Natalia; Lisacek, Frédérique; Sanchez, Jean-Charles; Müller, Markus

    2011-03-17

    Receiver operating characteristic (ROC) curves are useful tools to evaluate classifiers in biomedical and bioinformatics applications. However, conclusions are often reached through inconsistent use or insufficient statistical analysis. To support researchers in their ROC curves analysis we developed pROC, a package for R and S+ that contains a set of tools displaying, analyzing, smoothing and comparing ROC curves in a user-friendly, object-oriented and flexible interface. With data previously imported into the R or S+ environment, the pROC package builds ROC curves and includes functions for computing confidence intervals, statistical tests for comparing total or partial area under the curve or the operating points of different classifiers, and methods for smoothing ROC curves. Intermediary and final results are visualised in user-friendly interfaces. A case study based on published clinical and biomarker data shows how to perform a typical ROC analysis with pROC. pROC is a package for R and S+ specifically dedicated to ROC analysis. It proposes multiple statistical tests to compare ROC curves, and in particular partial areas under the curve, allowing proper ROC interpretation. pROC is available in two versions: in the R programming language or with a graphical user interface in the S+ statistical software. It is accessible at http://expasy.org/tools/pROC/ under the GNU General Public License. It is also distributed through the CRAN and CSAN public repositories, facilitating its installation.

  14. Corrected ROC analysis for misclassified binary outcomes.

    Science.gov (United States)

    Zawistowski, Matthew; Sussman, Jeremy B; Hofer, Timothy P; Bentley, Douglas; Hayward, Rodney A; Wiitala, Wyndy L

    2017-06-15

    Creating accurate risk prediction models from Big Data resources such as Electronic Health Records (EHRs) is a critical step toward achieving precision medicine. A major challenge in developing these tools is accounting for imperfect aspects of EHR data, particularly the potential for misclassified outcomes. Misclassification, the swapping of case and control outcome labels, is well known to bias effect size estimates for regression prediction models. In this paper, we study the effect of misclassification on accuracy assessment for risk prediction models and find that it leads to bias in the area under the curve (AUC) metric from standard ROC analysis. The extent of the bias is determined by the false positive and false negative misclassification rates as well as disease prevalence. Notably, we show that simply correcting for misclassification while building the prediction model is not sufficient to remove the bias in AUC. We therefore introduce an intuitive misclassification-adjusted ROC procedure that accounts for uncertainty in observed outcomes and produces bias-corrected estimates of the true AUC. The method requires that misclassification rates are either known or can be estimated, quantities typically required for the modeling step. The computational simplicity of our method is a key advantage, making it ideal for efficiently comparing multiple prediction models on very large datasets. Finally, we apply the correction method to a hospitalization prediction model from a cohort of over 1 million patients from the Veterans Health Administrations EHR. Implementations of the ROC correction are provided for Stata and R. Published 2017. This article is a U.S. Government work and is in the public domain in the USA. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  15. Statistical evaluation of diagnostic performance topics in ROC analysis

    CERN Document Server

    Zou, Kelly H; Bandos, Andriy I; Ohno-Machado, Lucila; Rockette, Howard E

    2016-01-01

    Statistical evaluation of diagnostic performance in general and Receiver Operating Characteristic (ROC) analysis in particular are important for assessing the performance of medical tests and statistical classifiers, as well as for evaluating predictive models or algorithms. This book presents innovative approaches in ROC analysis, which are relevant to a wide variety of applications, including medical imaging, cancer research, epidemiology, and bioinformatics. Statistical Evaluation of Diagnostic Performance: Topics in ROC Analysis covers areas including monotone-transformation techniques in parametric ROC analysis, ROC methods for combined and pooled biomarkers, Bayesian hierarchical transformation models, sequential designs and inferences in the ROC setting, predictive modeling, multireader ROC analysis, and free-response ROC (FROC) methodology. The book is suitable for graduate-level students and researchers in statistics, biostatistics, epidemiology, public health, biomedical engineering, radiology, medi...

  16. Applications of ROC analysis in diagnostic image evaluation

    International Nuclear Information System (INIS)

    Metz, C.E.

    1979-01-01

    The need for Receiver Operating Characteristic (ROC) analysis is indicated by a discussion of the limitations of accuracy and of sensitivity and specificity as indices of diagnostic detection or discrmination performance. The concept of a variable decision threshold is shown to lead in a natural way to the ROC curve as a means for specifying diagnostic performance. Practical techniques for measuring ROC curves are described, and directions for possible generalizations of conventional ROC analysis are indicated

  17. Large reservoirs: Chapter 17

    Science.gov (United States)

    Miranda, Leandro E.; Bettoli, Phillip William

    2010-01-01

    Large impoundments, defined as those with surface area of 200 ha or greater, are relatively new aquatic ecosystems in the global landscape. They represent important economic and environmental resources that provide benefits such as flood control, hydropower generation, navigation, water supply, commercial and recreational fisheries, and various other recreational and esthetic values. Construction of large impoundments was initially driven by economic needs, and ecological consequences received little consideration. However, in recent decades environmental issues have come to the forefront. In the closing decades of the 20th century societal values began to shift, especially in the developed world. Society is no longer willing to accept environmental damage as an inevitable consequence of human development, and it is now recognized that continued environmental degradation is unsustainable. Consequently, construction of large reservoirs has virtually stopped in North America. Nevertheless, in other parts of the world construction of large reservoirs continues. The emergence of systematic reservoir management in the early 20th century was guided by concepts developed for natural lakes (Miranda 1996). However, we now recognize that reservoirs are different and that reservoirs are not independent aquatic systems inasmuch as they are connected to upstream rivers and streams, the downstream river, other reservoirs in the basin, and the watershed. Reservoir systems exhibit longitudinal patterns both within and among reservoirs. Reservoirs are typically arranged sequentially as elements of an interacting network, filter water collected throughout their watersheds, and form a mosaic of predictable patterns. Traditional approaches to fisheries management such as stocking, regulating harvest, and in-lake habitat management do not always produce desired effects in reservoirs. As a result, managers may expend resources with little benefit to either fish or fishing. Some locally

  18. Receiver Operating Characteristics (ROCs) in Recognition Memory: A Review

    Science.gov (United States)

    Yonelinas, Andrew P.; Parks, Colleen M.

    2007-01-01

    Receiver operating characteristic (ROC) analysis is being used increasingly to examine the memory processes underlying recognition memory. The authors discuss the methodological issues involved in conducting and analyzing ROC results, describe the various models that have been developed to account for these results, review the behavioral empirical…

  19. Technology Exhibition

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1979-09-15

    Linked to the 25th Anniversary celebrations, an exhibition of some of CERN's technological achievements was opened on 22 June. Set up in a new 600 m{sup 2} Exhibition Hall on the CERN site, the exhibition is divided into eight technology areas — magnets, vacuum, computers and data handling, survey and alignment, radiation protection, beam monitoring and handling, detectors, and workshop techniques.

  20. Immersive Exhibitions

    DEFF Research Database (Denmark)

    Achiam, Marianne

    2015-01-01

    The immersive exhibition is a specialized exhibition genre in museums, which creates the illusion of time and place by representing key characteristics of a reference world and by integrating the visitor in this three-dimensionally reconstructed world (Mortensen 2010). A successful representation...... of the reference world depends on three criteria: whether the exhibition is staged as a coherent whole with all the displayed objects supporting the representation, whether the visitor is integrated as a component of the exhibition, and whether the content and message of the exhibition become dramatized...

  1. Compare diagnostic tests using transformation-invariant smoothed ROC curves⋆

    Science.gov (United States)

    Tang, Liansheng; Du, Pang; Wu, Chengqing

    2012-01-01

    Receiver operating characteristic (ROC) curve, plotting true positive rates against false positive rates as threshold varies, is an important tool for evaluating biomarkers in diagnostic medicine studies. By definition, ROC curve is monotone increasing from 0 to 1 and is invariant to any monotone transformation of test results. And it is often a curve with certain level of smoothness when test results from the diseased and non-diseased subjects follow continuous distributions. Most existing ROC curve estimation methods do not guarantee all of these properties. One of the exceptions is Du and Tang (2009) which applies certain monotone spline regression procedure to empirical ROC estimates. However, their method does not consider the inherent correlations between empirical ROC estimates. This makes the derivation of the asymptotic properties very difficult. In this paper we propose a penalized weighted least square estimation method, which incorporates the covariance between empirical ROC estimates as a weight matrix. The resulting estimator satisfies all the aforementioned properties, and we show that it is also consistent. Then a resampling approach is used to extend our method for comparisons of two or more diagnostic tests. Our simulations show a significantly improved performance over the existing method, especially for steep ROC curves. We then apply the proposed method to a cancer diagnostic study that compares several newly developed diagnostic biomarkers to a traditional one. PMID:22639484

  2. Consistency Results for the ROC Curves of Fused Classifiers

    National Research Council Canada - National Science Library

    Bjerkaas, Kristopher

    2004-01-01

    .... An established performance quantifier is the Receiver Operating Characteristic (ROC) curve, which allows one to view the probability of detection versus the probability of false alarm in one graph...

  3. Test for the statistical significance of differences between ROC curves

    International Nuclear Information System (INIS)

    Metz, C.E.; Kronman, H.B.

    1979-01-01

    A test for the statistical significance of observed differences between two measured Receiver Operating Characteristic (ROC) curves has been designed and evaluated. The set of observer response data for each ROC curve is assumed to be independent and to arise from a ROC curve having a form which, in the absence of statistical fluctuations in the response data, graphs as a straight line on double normal-deviate axes. To test the significance of an apparent difference between two measured ROC curves, maximum likelihood estimates of the two parameters of each curve and the associated parameter variances and covariance are calculated from the corresponding set of observer response data. An approximate Chi-square statistic with two degrees of freedom is then constructed from the differences between the parameters estimated for each ROC curve and from the variances and covariances of these estimates. This statistic is known to be truly Chi-square distributed only in the limit of large numbers of trials in the observer performance experiments. Performance of the statistic for data arising from a limited number of experimental trials was evaluated. Independent sets of rating scale data arising from the same underlying ROC curve were paired, and the fraction of differences found (falsely) significant was compared to the significance level, α, used with the test. Although test performance was found to be somewhat dependent on both the number of trials in the data and the position of the underlying ROC curve in the ROC space, the results for various significance levels showed the test to be reliable under practical experimental conditions

  4. ROC Analysis for Evaluation of Radiation Biodosimetry Technologies

    International Nuclear Information System (INIS)

    Williams, Benjamin B.; Swartz, Harold M.; Flood, Ann Barry; Demidenko, Eugene

    2016-01-01

    Receiver operating characteristic (ROC) analysis is a fundamental tool used for the evaluation and comparison of diagnostic systems that provides estimates of the combinations of sensitivity and specificity that can be achieved with a given technique. Along with critical considerations of practical limitations, such as throughput and time to availability of results, ROC analyses can be applied to provide meaningful assessments and comparisons of available biodosimetry methods. Accordingly, guidance from the Food and Drug Administration to evaluate biodosimetry devices recommends using ROC analysis. However, the existing literature for the numerous biodosimetry methods that have been developed to address the needs for triage either do not contain ROC analyses or present ROC analyses where the dose distributions of the study samples are not representative of the populations to be screened. The use of non-representative sample populations can result in a significant spectrum bias, where estimated performance metrics do not accurately characterize the true performance under real-world conditions. Particularly, in scenarios where a large group of people is screened because they were potentially exposed in a large-scale radiation event, directly measured population data do not exist. However, a number of complex simulations have been performed and reported in the literature that provide estimates of the required dose distributions. Based on these simulations and reported data about the output and uncertainties of biodosimetry assays, we illustrate how ROC curves can be generated that incorporate a realistic representative sample. A technique to generate ROC curves for biodosimetry data is presented along with representative ROC curves, summary statistics and discussion based on published data for triage-ready electron paramagnetic resonance in vivo tooth dosimetry, the dicentric chromosome assay and quantitative polymerase chain reaction assay. We argue that this

  5. Exhibit Engineering

    DEFF Research Database (Denmark)

    Mortensen, Marianne Foss

    Science museums define the objectives of their exhibitions in terms of visitor learning outcomes. Yet, exhibit designers lack theoretical and empirical research findings on which to base the creation of such educational environments. Here, this shortcoming is addressed through the development...... of tools and processes to guide the design of educational science exhibits. The guiding paradigm for this development is design-based research, which is characterised by an iterative cycle of design, enactment, and analysis. In the design phase, an educational intervention is planned and carried out based...... on the generation of theoretical ideas for exhibit design is offered in a fourth and parallel research undertaking, namely the application of the notion of cultural border-crossing to a hypothetical case of exhibit design....

  6. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.

    1992-01-01

    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neural reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers, geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  7. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.

    1992-01-01

    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neutral reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  8. ROC Analysis of Diagnostic Performance in Liver Scan

    International Nuclear Information System (INIS)

    Lee, Myung Chul; Moon, Dyuk Hyuk; Koh, Chang Soon; Matumoto, Toru; Tateno, Yukio

    1988-01-01

    To evaluate diagnostic accuracy of liver scintigraphy we analysed liver scans of 143 normal and 258 patients with various liver diseases. Three ROC curves for SOL, liver cirrhosis and diffuse liver disease were fitted using rating methods and areas under the ROC curves and their standard errors were calculated by the trapezoidal rule and the variance of the Wilcoxon statistic suggested by McNeil. We compared these results with that of National Institute of Radiological Science in Japan. 1) The sensitivity of liver scintigraphy was 74.2% in SOL, 71.8% in liver cirrhosis and 34.8% in diffuse liver disease. The specificity was 96.0% in SOL, 94.2% in liver cirrhosis and 87.6% in diffuse liver disease. 2) ROC curves of SOL and liver cirrhosis approached the upper left-hand corner closer than that of diffuse liver disease. Area (± standard error) under the ROC curve was 0.868±0.024 in SOL and 0.867±0.028 in liver cirrhosis. These were significantly higher than 0.658±0.043 in diffuse liver disease. 3) There was no interobserver difference in terms of ROC curves. But low sensitivity and high specificity of authors' SOL diagnosis suggested we used more strict decision threshold.

  9. ROC analysis of diagnostic performance in liver scintigraphy

    International Nuclear Information System (INIS)

    Fritz, S.L.; Preston, D.F.; Gallagher, J.H.

    1981-01-01

    Studies on the accuracy of liver scintigraphy for the detection of metastases were assembled from 38 sources in the medical literature. An ROC curve was fitted to the observed values of sensitivity and specificity using an algorithm developed by Ogilvie and Creelman. This ROC curve fitted the data better than average sensitivity and specificity values in each of four subsets of the data. For the subset dealing with Tc-99m sulfur colloid scintigraphy, performed for detection of suspected metastases and containing data on 2800 scans from 17 independent series, it was not possible to reject the hypothesis that interobserver variation was entirely due to the use of different decision thresholds by the reporting clinicians. Thus the ROC curve obtained is a reasonable baseline estimate of the performance potentially achievable in today's clinical setting. Comparison of new reports with these data is impossible, but is limited by the small sample sizes in most reported series

  10. ROC analysis of diagnostic performance in liver scintigraphy.

    Science.gov (United States)

    Fritz, S L; Preston, D F; Gallagher, J H

    1981-02-01

    Studies on the accuracy of liver scintigraphy for the detection of metastases were assembled from 38 sources in the medical literature. An ROC curve was fitted to the observed values of sensitivity and specificity using an algorithm developed by Ogilvie and Creelman. This ROC curve fitted the data better than average sensitivity and specificity values in each of four subsets of the data. For the subset dealing with Tc-99m sulfur colloid scintigraphy, performed for detection of suspected metastases and containing data on 2800 scans from 17 independent series, it was not possible to reject the hypothesis that interobserver variation was entirely due to the use of different decision thresholds by the reporting clinicians. Thus the ROC curve obtained is a reasonable baseline estimate of the performance potentially achievable in today's clinical setting. Comparison of new reports with these data is possible, but is limited by the small sample sizes in most reported series.

  11. Human Exhibitions

    DEFF Research Database (Denmark)

    Andreassen, Rikke

    light on the staging of exhibitions, the daily life of the exhibitees, the wider connections between shows across Europe and the thinking of the time on matters of race, science, gender and sexuality. A window onto contemporary racial understandings, the book presents interviews with the descendants...... of displayed people, connecting the attitudes and science of the past with both our (continued) modern fascination with ‘the exotic’, and contemporary language and popular culture. As such, it will be of interest to scholars of sociology, anthropology and history working in the areas of gender and sexuality...

  12. "Remember" source memory ROCs indicate recollection is a continuous process.

    Science.gov (United States)

    Slotnick, Scott D

    2010-01-01

    The dual process model assumes memory is based on recollection (retrieval with specific detail) or familiarity (retrieval without specific detail). A current debate is whether recollection is a threshold process or, like familiarity, is a continuous process. In the present study two continuous models and two threshold models of recollection were evaluated using receiver operating characteristic (ROC) analysis. These models included the continuous signal detection unequal variance model and the threshold dual process model. In the study phase of three experiments, objects were presented to the right or left of fixation. At test, participants made either remember-know responses or item confidence responses followed by source memory (spatial location) confidence ratings. Recollection-based ROCs were generated from source memory confidence ratings associated with "remember" responses (in Experiments 1-2) or the highest item confidence responses (in Experiment 3). Neither threshold model adequately fit any of the recollection-based ROCs. By contrast, one or both of the continuous models adequately fit all of the recollection-based ROCs. The present results indicate recollection and familiarity are both continuous processes.

  13. ROC analysis in gammagraphic diagnosis of hepatic cirrhosis

    International Nuclear Information System (INIS)

    Hdez-Armas, J.; Allende, A.; Alarco, R.; Panero, J.; Oton, C.

    1982-01-01

    An application of the ROC statistical method is described on a sample of 161 patients who underwent hepatic gammagraphy and biopsies obtained by laparsocopy, and of whom 90 were found to have hepatic cirrhosis according to pathological anatomy. Five decision thresholds have been established in the elaboration of the gammagraphic diagnosis of cirrhosis. The true positive fraction (TPF) and false positive fraction (FPF) of these five thresholds are shown on an ordinate axis and an ROC curve is obtained. By means of a simplified cost-benefit analysis the optimal point of operation for this type of diagnosis is determined on this curve, according to which the diagnosis of cirrhosis should be considered positive when alterations in the size of the liver and distribution of the isotope in the liver are found simultaneously with splenomegaly. (orig.)

  14. On the form of ROCs constructed from confidence ratings.

    Science.gov (United States)

    Malmberg, Kenneth J

    2002-03-01

    A classical question for memory researchers is whether memories vary in an all-or-nothing, discrete manner (e.g., stored vs. not stored, recalled vs. not recalled), or whether they vary along a continuous dimension (e.g., strength, similarity, or familiarity). For yes-no classification tasks, continuous- and discrete-state models predict nonlinear and linear receiver operating characteristics (ROCs), respectively (D. M. Green & J. A. Swets, 1966; N. A. Macmillan & C. D. Creelman, 1991). Recently, several authors have assumed that these predictions are generalizable to confidence ratings tasks (J. Qin, C. L. Raye, M. K. Johnson, & K. J. Mitchell, 2001; S. D. Slotnick, S. A. Klein, C. S. Dodson, & A. P. Shimamura, 2000, and A. P. Yonelinas, 1999). This assumption is shown to be unwarranted by showing that discrete-state ratings models predict both linear and nonlinear ROCs. The critical factor determining the form of the discrete-state ROC is the response strategy adopted by the classifier.

  15. Reliability in NDT: ROC study of radiographic weld inspections

    International Nuclear Information System (INIS)

    Nockemann, C.; Heidt, H.; Thomsen, N.

    1991-01-01

    The complexity of modern nondestructive testing (NDT) equipment as well as the demand for high reliability in many industries makes it necessary to have a tool to assess different NDT techniques and devices quickly. As for cost benefit considerations, a measure of accuracy has to include not only the number of correctly detected defects but also the corresponding number of false indications. In order to satisfy a variety of security demands this ratio of true and false indications must be known for a wide range of defect dimensions to be included in the defect count. This information will be provided by only one ROC (relative operating characteristic) study of inspection data using the rating confidence method. An expanded ROC version also yields an assessment of the accuracy of the defect classification and of the correctness of the indicated defect importance. All these measures of performance can also be called up for each individual inspector. For demonstrating the power of the method it is applied to ascertain the difference in detection performance of three distinct experimental modalities in the radiographic testing of welded joints. In order to be capable of drawing conclusions reliably, the study is completed by statistical significance tests. The paper shows the usefulness of ROC for performance assessment in NDT and gives an illustration of what can be done with which effort. (Author)

  16. Accrual of ROCs LECs and REGOs. Phase 3a: pre-determined entitlements to ROCs for small microgenerators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report describes a proposed scheme to enable microgenerators in the UK to claim Renewable Obligation Certificates (ROCs) on the basis of predetermined estimates of output rather than data from meters. The aim of the scheme, which has been developed following discussions with representatives of the microgeneration community in the UK, is to make it easier for small generators to access to ROCs and thus encourage householders and smaller commercial/business users to install renewable microgeneration technologies. The work was commissioned as part of the review of the Renewables Obligation. The report considers: background information; the Australian scheme for small generating units; eligibility and entitlements; the operation of the scheme; new procedural and legislative requirements; measures to protect and improve the Renewables Obligation; alterative approaches; scheme benefits; and recommendations. An overview of the scheme's key features is given in the report's executive summary.

  17. Trypanosoma cruzi strains isolated from human, vector, and animal reservoir in the same endemic region in Mexico and typed as T. cruzi I, discrete typing unit 1 exhibit considerable biological diversity

    Directory of Open Access Journals (Sweden)

    María del Carmen Sánchez-Guillén

    2006-09-01

    Full Text Available In this study, three strains of Trypanosoma cruzi were isolated at the same time and in the same endemic region in Mexico from a human patient with chronic chagasic cardiomyopathy (RyC-H; vector (Triatoma barberi (RyC-V; and rodent reservoir (Peromyscus peromyscus (RyC-R. The three strains were characterized by multilocus enzyme electrophoresis, random amplified polymorphic DNA, and by pathological profiles in experimental animals (biodemes. Based on the analysis of genetic markers the three parasite strains were typed as belonging to T. cruzi I major group, discrete typing unit 1. The pathological profile of RyC-H and RyC-V strains indicated medium virulence and low mortality and, accordingly, the strains should be considered as belonging to biodeme Type III. On the other hand, the parasites from RyC-R strain induced more severe inflammatory processes and high mortality (> 40% and were considered as belonging to biodeme Type II. The relationship between genotypes and biological characteristics in T. cruzi strains is still debated and not clearly understood. An expert committee recommended in 1999 that Biodeme Type III would correspond to T. cruzi I group, whereas Biodeme Type II, to T. cruzi II group. Our findings suggest that, at least for Mexican isolates, this correlation does not stand and that biological characteristics such as pathogenicity and virulence could be determined by factors different from those identified in the genotypic characterization

  18. Medical decision making tools: Bayesian analysis and ROC analysis

    International Nuclear Information System (INIS)

    Lee, Byung Do

    2006-01-01

    During the diagnostic process of the various oral and maxillofacial lesions, we should consider the following: 'When should we order diagnostic tests? What tests should be ordered? How should we interpret the results clinically? And how should we use this frequently imperfect information to make optimal medical decision?' For the clinicians to make proper judgement, several decision making tools are suggested. This article discusses the concept of the diagnostic accuracy (sensitivity and specificity values) with several decision making tools such as decision matrix, ROC analysis and Bayesian analysis. The article also explain the introductory concept of ORAD program

  19. Mutations in the LRRK2 Roc-COR tandem domain link Parkinson's disease to Wnt signalling pathways.

    Science.gov (United States)

    Sancho, Rosa M; Law, Bernard M H; Harvey, Kirsten

    2009-10-15

    Mutations in PARK8, encoding LRRK2, are the most common known cause of Parkinson's disease. The LRRK2 Roc-COR tandem domain exhibits GTPase activity controlling LRRK2 kinase activity via an intramolecular process. We report the interaction of LRRK2 with the dishevelled family of phosphoproteins (DVL1-3), key regulators of Wnt (Wingless/Int) signalling pathways important for axon guidance, synapse formation and neuronal maintenance. Interestingly, DVLs can interact with and mediate the activation of small GTPases with structural similarity to the LRRK2 Roc domain. The LRRK2 Roc-COR domain and the DVL1 DEP domain were necessary and sufficient for LRRK2-DVL1 interaction. Co-expression of DVL1 increased LRRK2 steady-state protein levels, an effect that was dependent on the DEP domain. Strikingly, LRRK2-DVL1-3 interactions were disrupted by the familial PARK8 mutation Y1699C, whereas pathogenic mutations at residues R1441 and R1728 strengthened LRRK2-DVL1 interactions. Co-expression of DVL1 with LRRK2 in mammalian cells resulted in the redistribution of LRRK2 to typical cytoplasmic DVL1 aggregates in HEK293 and SH-SY5Y cells and co-localization in neurites and growth cones of differentiated dopaminergic SH-SY5Y cells. This is the first report of the modulation of a key LRRK2-accessory protein interaction by PARK8 Roc-COR domain mutations segregating with Parkinson's disease. Since the DVL1 DEP domain is known to be involved in the regulation of small GTPases, we propose that: (i) DVLs may influence LRRK2 GTPase activity, and (ii) Roc-COR domain mutations modulating LRRK2-DVL interactions indirectly influence kinase activity. Our findings also link LRRK2 to Wnt signalling pathways, suggesting novel pathogenic mechanisms and new targets for genetic analysis in Parkinson's disease.

  20. A semiparametric separation curve approach for comparing correlated ROC data from multiple markers

    Science.gov (United States)

    Tang, Liansheng Larry; Zhou, Xiao-Hua

    2012-01-01

    In this article we propose a separation curve method to identify the range of false positive rates for which two ROC curves differ or one ROC curve is superior to the other. Our method is based on a general multivariate ROC curve model, including interaction terms between discrete covariates and false positive rates. It is applicable with most existing ROC curve models. Furthermore, we introduce a semiparametric least squares ROC estimator and apply the estimator to the separation curve method. We derive a sandwich estimator for the covariance matrix of the semiparametric estimator. We illustrate the application of our separation curve method through two real life examples. PMID:23074360

  1. Optimal Joint Detection and Estimation That Maximizes ROC-Type Curves.

    Science.gov (United States)

    Wunderlich, Adam; Goossens, Bart; Abbey, Craig K

    2016-09-01

    Combined detection-estimation tasks are frequently encountered in medical imaging. Optimal methods for joint detection and estimation are of interest because they provide upper bounds on observer performance, and can potentially be utilized for imaging system optimization, evaluation of observer efficiency, and development of image formation algorithms. We present a unified Bayesian framework for decision rules that maximize receiver operating characteristic (ROC)-type summary curves, including ROC, localization ROC (LROC), estimation ROC (EROC), free-response ROC (FROC), alternative free-response ROC (AFROC), and exponentially-transformed FROC (EFROC) curves, succinctly summarizing previous results. The approach relies on an interpretation of ROC-type summary curves as plots of an expected utility versus an expected disutility (or penalty) for signal-present decisions. We propose a general utility structure that is flexible enough to encompass many ROC variants and yet sufficiently constrained to allow derivation of a linear expected utility equation that is similar to that for simple binary detection. We illustrate our theory with an example comparing decision strategies for joint detection-estimation of a known signal with unknown amplitude. In addition, building on insights from our utility framework, we propose new ROC-type summary curves and associated optimal decision rules for joint detection-estimation tasks with an unknown, potentially-multiple, number of signals in each observation.

  2. Transformation-invariant and nonparametric monotone smooth estimation of ROC curves.

    Science.gov (United States)

    Du, Pang; Tang, Liansheng

    2009-01-30

    When a new diagnostic test is developed, it is of interest to evaluate its accuracy in distinguishing diseased subjects from non-diseased subjects. The accuracy of the test is often evaluated by receiver operating characteristic (ROC) curves. Smooth ROC estimates are often preferable for continuous test results when the underlying ROC curves are in fact continuous. Nonparametric and parametric methods have been proposed by various authors to obtain smooth ROC curve estimates. However, there are certain drawbacks with the existing methods. Parametric methods need specific model assumptions. Nonparametric methods do not always satisfy the inherent properties of the ROC curves, such as monotonicity and transformation invariance. In this paper we propose a monotone spline approach to obtain smooth monotone ROC curves. Our method ensures important inherent properties of the underlying ROC curves, which include monotonicity, transformation invariance, and boundary constraints. We compare the finite sample performance of the newly proposed ROC method with other ROC smoothing methods in large-scale simulation studies. We illustrate our method through a real life example. Copyright (c) 2008 John Wiley & Sons, Ltd.

  3. Chickamauga reservoir embayment study - 1990

    Energy Technology Data Exchange (ETDEWEB)

    Meinert, D.L.; Butkus, S.R.; McDonough, T.A.

    1992-12-01

    The objectives of this report are three-fold: (1) assess physical, chemical, and biological conditions in the major embayments of Chickamauga Reservoir; (2) compare water quality and biological conditions of embayments with main river locations; and (3) identify any water quality concerns in the study embayments that may warrant further investigation and/or management actions. Embayments are important areas of reservoirs to be considered when assessments are made to support water quality management plans. In general, embayments, because of their smaller size (water surface areas usually less than 1000 acres), shallower morphometry (average depth usually less than 10 feet), and longer detention times (frequently a month or more), exhibit more extreme responses to pollutant loadings and changes in land use than the main river region of the reservoir. Consequently, embayments are often at greater risk of water quality impairments (e.g. nutrient enrichment, filling and siltation, excessive growths of aquatic plants, algal blooms, low dissolved oxygen concentrations, bacteriological contamination, etc.). Much of the secondary beneficial use of reservoirs occurs in embayments (viz. marinas, recreation areas, parks and beaches, residential development, etc.). Typically embayments comprise less than 20 percent of the surface area of a reservoir, but they often receive 50 percent or more of the water-oriented recreational use of the reservoir. This intensive recreational use creates a potential for adverse use impacts if poor water quality and aquatic conditions exist in an embayment.

  4. Analyzing ROC curves using the effective set-size model

    Science.gov (United States)

    Samuelson, Frank W.; Abbey, Craig K.; He, Xin

    2018-03-01

    The Effective Set-Size model has been used to describe uncertainty in various signal detection experiments. The model regards images as if they were an effective number (M*) of searchable locations, where the observer treats each location as a location-known-exactly detection task with signals having average detectability d'. The model assumes a rational observer behaves as if he searches an effective number of independent locations and follows signal detection theory at each location. Thus the location-known-exactly detectability (d') and the effective number of independent locations M* fully characterize search performance. In this model the image rating in a single-response task is assumed to be the maximum response that the observer would assign to these many locations. The model has been used by a number of other researchers, and is well corroborated. We examine this model as a way of differentiating imaging tasks that radiologists perform. Tasks involving more searching or location uncertainty may have higher estimated M* values. In this work we applied the Effective Set-Size model to a number of medical imaging data sets. The data sets include radiologists reading screening and diagnostic mammography with and without computer-aided diagnosis (CAD), and breast tomosynthesis. We developed an algorithm to fit the model parameters using two-sample maximum-likelihood ordinal regression, similar to the classic bi-normal model. The resulting model ROC curves are rational and fit the observed data well. We find that the distributions of M* and d' differ significantly among these data sets, and differ between pairs of imaging systems within studies. For example, on average tomosynthesis increased readers' d' values, while CAD reduced the M* parameters. We demonstrate that the model parameters M* and d' are correlated. We conclude that the Effective Set-Size model may be a useful way of differentiating location uncertainty from the diagnostic uncertainty in medical

  5. Comparison of Paired ROC Curves through a Two-Stage Test.

    Science.gov (United States)

    Yu, Wenbao; Park, Eunsik; Chang, Yuan-Chin Ivan

    2015-01-01

    The area under the receiver operating characteristic (ROC) curve (AUC) is a popularly used index when comparing two ROC curves. Statistical tests based on it for analyzing the difference have been well developed. However, this index is less informative when two ROC curves cross and have similar AUCs. In order to detect differences between ROC curves in such situations, a two-stage nonparametric test that uses a shifted area under the ROC curve (sAUC), along with AUCs, is proposed for paired designs. The new procedure is shown, numerically, to be effective in terms of power under a wide range of scenarios; additionally, it outperforms two conventional ROC-type tests, especially when two ROC curves cross each other and have similar AUCs. Larger sAUC implies larger partial AUC at the range of low false-positive rates in this case. Because high specificity is important in many classification tasks, such as medical diagnosis, this is an appealing characteristic. The test also implicitly analyzes the equality of two commonly used binormal ROC curves at every operating point. We also apply the proposed method to synthesized data and two real examples to illustrate its usefulness in practice.

  6. Receiver operating characteristic (ROC) curves: review of methods with applications in diagnostic medicine

    Science.gov (United States)

    Obuchowski, Nancy A.; Bullen, Jennifer A.

    2018-04-01

    Receiver operating characteristic (ROC) analysis is a tool used to describe the discrimination accuracy of a diagnostic test or prediction model. While sensitivity and specificity are the basic metrics of accuracy, they have many limitations when characterizing test accuracy, particularly when comparing the accuracies of competing tests. In this article we review the basic study design features of ROC studies, illustrate sample size calculations, present statistical methods for measuring and comparing accuracy, and highlight commonly used ROC software. We include descriptions of multi-reader ROC study design and analysis, address frequently seen problems of verification and location bias, discuss clustered data, and provide strategies for testing endpoints in ROC studies. The methods are illustrated with a study of transmission ultrasound for diagnosing breast lesions.

  7. Britain exhibition at CERN

    CERN Multimedia

    Bertin; CERN PhotoLab

    1969-01-01

    The United Kingdom inaugurated the Industrial Exhibitions in 1968, and it wasn't till 1971 that other countries staged exhibitions at CERN. This photo was taken in 1969, at the second British exhibition, where 16 companies were present.

  8. Large-field image intensifiers versus conventional chest radiography: ROC study with simulated interstitial disease

    International Nuclear Information System (INIS)

    Winter, L.H.L.; Chakraborty, D.P.; Waes, P.F.G.M.

    1988-01-01

    Two image intensifier tubes have recently been introduced whose large imaging area makes them suitable for chest imaging (Phillips Pulmodiagnost TLX slit II and Siemens TX 57 large entrance field II). Both modalities present a 10 x 10-cm hard copy image to the radiologist. A receiver operating characteristic (ROC) curve study with simulated interstitial disease was performed to compare the image quality of these image intensifiers with conventional chest images. The relative ranking in terms of decreasing ROC areas was Siemens, conventional, and Philips. Compared with conventional imaging, none of the differences in ROC curve area were statistically significant at the 5% level

  9. El Rocío y el turismo de peregrinación

    OpenAIRE

    Villa Díaz, Águeda

    2006-01-01

    La palabra Rocío está llena de significados: una virgen, una romería y una aldea vecinas de la marisma del Guadalquivir bautizadas por un fenómeno microclimático, como es la diaria y fecunda presencia de agua en su mínima expresión las gotas de rocío. Pero este nombre evoca, sobre todo, a la devoción a Nuestra Señora del Rocío Patrona de Almonte y a su anual romería de Pentecostés el Rocío Grande. Esta romería ha conocido una gran expansión en los últimos cincuenta años, atrayendo peregrinos ...

  10. Quantitative evaluation of visual detection performance in medicine: ROC analysis and determination of diagnostic benefit

    International Nuclear Information System (INIS)

    Metz, C.E.; Starr, S.J.; Lusted, L.B.

    1976-01-01

    An ROC curve provides an empirical description of the trade-offs which are possible among the various types of correct and incorrect decisions as the human decision-maker varies one or more confidence thresholds. Conventional ROC curves measured in simple decision-making situations can, in some cases, be used to predict human decision performance in more complex situations. By considering both the consequences of the various types of diagnostic decisions and the overhead cost of a diagnostic study, one can use the ROC curve to evaluate the diagnostic usefulness of a study in any particular clinical context. Since the ROC curve describes the possible relationships among the probabilities of the various types of correct and incorrect decisions, it plays a central role in optimizing diagnostic strategies using the general techniques of decision analysis. Applications in radiographic image evaluation are described

  11. Comparison of rat epidermal keratinocyte organotypic culture (ROC) with intact human skin

    DEFF Research Database (Denmark)

    Pappinen, Sari; Hermansson, Martin; Kuntsche, Judith

    2008-01-01

    study was to compare the stratum corneum lipid content of ROC with the corresponding material from human skin. The lipid composition was determined by thin-layer chromatography (TLC) and mass-spectrometry, and the thermal phase transitions of stratum corneum were studied by differential scanning...... calorimetry (DSC). All major lipid classes of the stratum corneum were present in ROC in a similar ratio as found in human stratum corneum. Compared to human skin, the level of non-hydroxyacid-sphingosine ceramide (NS) was increased in ROC, while alpha-hydroxyacid-phytosphingosine ceramide (AP) and non...... compared to human skin, in agreement with the results from DSC. ROC underwent a lipid lamellar order to disorder transition (T2) at a slightly lower temperature (68 degrees C) than human skin (74 degrees C). These differences in stratum corneum lipid composition and the thermal phase transitions may...

  12. SILTATION IN RESERVOIRS

    African Journals Online (AJOL)

    Keywords: reservoir model, siltation, sediment, catchment, sediment transport. 1. Introduction. Sediment ... rendered water storage structures useless in less than 25 years. ... reservoir, thus reducing the space available for water storage and ...

  13. Reservoir fisheries of Asia

    International Nuclear Information System (INIS)

    Silva, S.S. De.

    1990-01-01

    At a workshop on reservoir fisheries research, papers were presented on the limnology of reservoirs, the changes that follow impoundment, fisheries management and modelling, and fish culture techniques. Separate abstracts have been prepared for three papers from this workshop

  14. Reader characteristics linked to detection of pulmonary nodules on radiographs: ROC vs. JAFROC analyses of performance

    Science.gov (United States)

    Kohli, Akshay; Robinson, John W.; Ryan, John; McEntee, Mark F.; Brennan, Patrick C.

    2011-03-01

    The purpose of this study is to explore whether reader characteristics are linked to heightened levels of diagnostic performance in chest radiology using receiver operating characteristic (ROC) and jackknife free response ROC (JAFROC) methodologies. A set of 40 postero-anterior chest radiographs was developed, of which 20 were abnormal containing one or more simulated nodules, of varying subtlety. Images were independently reviewed by 12 boardcertified radiologists including six chest specialists. The observer performance was measured in terms of ROC and JAFROC scores. For the ROC analysis, readers were asked to rate their degree of suspicion for the presence of nodules by using a confidence rating scale (1-6). JAFROC analysis required the readers to locate and rate as many suspicious areas as they wished using the same scale and resultant data were used to generate Az and FOM scores for ROC and JAFROC analyses respectively. Using Pearson methods, scores of performance were correlated with 7 reader characteristics recorded using a questionnaire. JAFROC analysis showed that improved reader performance was significantly (pchest specialty (pchest radiographs (pchest readings per year (pchest radiographs (pchest specialty, hours reading per week and number of radiographs read per year. Also, JAFROC is a more powerful predictor of performance as compared to ROC.

  15. Rocker: Open source, easy-to-use tool for AUC and enrichment calculations and ROC visualization.

    Science.gov (United States)

    Lätti, Sakari; Niinivehmas, Sanna; Pentikäinen, Olli T

    2016-01-01

    Receiver operating characteristics (ROC) curve with the calculation of area under curve (AUC) is a useful tool to evaluate the performance of biomedical and chemoinformatics data. For example, in virtual drug screening ROC curves are very often used to visualize the efficiency of the used application to separate active ligands from inactive molecules. Unfortunately, most of the available tools for ROC analysis are implemented into commercially available software packages, or are plugins in statistical software, which are not always the easiest to use. Here, we present Rocker, a simple ROC curve visualization tool that can be used for the generation of publication quality images. Rocker also includes an automatic calculation of the AUC for the ROC curve and Boltzmann-enhanced discrimination of ROC (BEDROC). Furthermore, in virtual screening campaigns it is often important to understand the early enrichment of active ligand identification, for this Rocker offers automated calculation routine. To enable further development of Rocker, it is freely available (MIT-GPL license) for use and modifications from our web-site (http://www.jyu.fi/rocker).

  16. Digital collections and exhibits

    CERN Document Server

    Denzer, Juan

    2015-01-01

    Today's libraries are taking advantage of cutting-edge technologies such as flat panel displays using touch, sound, and hands-free motions to design amazing exhibits using everything from simple computer hardware to advanced technologies such as the Microsoft Kinect. Libraries of all types are striving to add new interactive experiences for their patrons through exciting digital exhibits, both online and off. Digital Collections and Exhibits takes away the mystery of designing stunning digital exhibits to spotlight library trea

  17. Exhibiting Epistemic Objects

    DEFF Research Database (Denmark)

    Tybjerg, Karin

    2017-01-01

    of exhibiting epistemic objects that utilize their knowledge-generating potential and allow them to continue to stimulate curiosity and generate knowledge in the exhibition. The epistemic potential of the objects can then be made to work together with the function of the exhibition as a knowledge-generating set...

  18. Discrimination? - Exhibition of posters

    OpenAIRE

    Jakimovska, Jana

    2017-01-01

    Participation in the exhibition with the students form the Art Academy. The exhibition consisted of 15 posters tackling the subjects of hate speech and discrimination. The exhibition happened thanks to the invitation of the Faculty of Law at UGD, and it was a part of a larger event of launching books on the aforementioned subjects.

  19. The ROC Toolbox: A toolbox for analyzing receiver-operating characteristics derived from confidence ratings.

    Science.gov (United States)

    Koen, Joshua D; Barrett, Frederick S; Harlow, Iain M; Yonelinas, Andrew P

    2017-08-01

    Signal-detection theory, and the analysis of receiver-operating characteristics (ROCs), has played a critical role in the development of theories of episodic memory and perception. The purpose of the current paper is to present the ROC Toolbox. This toolbox is a set of functions written in the Matlab programming language that can be used to fit various common signal detection models to ROC data obtained from confidence rating experiments. The goals for developing the ROC Toolbox were to create a tool (1) that is easy to use and easy for researchers to implement with their own data, (2) that can flexibly define models based on varying study parameters, such as the number of response options (e.g., confidence ratings) and experimental conditions, and (3) that provides optimal routines (e.g., Maximum Likelihood estimation) to obtain parameter estimates and numerous goodness-of-fit measures.The ROC toolbox allows for various different confidence scales and currently includes the models commonly used in recognition memory and perception: (1) the unequal variance signal detection (UVSD) model, (2) the dual process signal detection (DPSD) model, and (3) the mixture signal detection (MSD) model. For each model fit to a given data set the ROC toolbox plots summary information about the best fitting model parameters and various goodness-of-fit measures. Here, we present an overview of the ROC Toolbox, illustrate how it can be used to input and analyse real data, and finish with a brief discussion on features that can be added to the toolbox.

  20. Geisinger high-risk osteoporosis clinic (HiROC): 2013-2015 FLS performance analysis.

    Science.gov (United States)

    Dunn, P; Webb, D; Olenginski, T P

    2018-02-01

    Geisinger Health System (GHS) high-risk osteoporosis clinic (HiROC), which treats patients with low-trauma, fragility fractures, reports their 2013-2015 performance measures in secondary fracture prevention. This fracture liaison service (FLS) pathway treats 75% of high-risk, drug eligible patients, compared to 13.8% in GHS primary care. This performance points to the need for more FLS programs throughout the world. The purpose of this study is to analyze and report ongoing performance measures in outpatient and inpatient high-risk osteoporosis clinic (HiROC) program designed for patients with low-trauma, fragility fractures. Retrospective chart review of outpatient HiROC (511 patients) and inpatient HiROC (1279 patients) performance from 2013 to 2015 is reported within Geisinger Health System (GHS). Similar to a prior report, we document that Geisinger's branded outpatient and inpatient HiROC pathways continue to function as an all-fracture FLS. Importantly, this analysis emphasizes the importance of FLS care that HiROC's treatment rate of 75% was markedly superior to GHS-PCP care of 13.8%. However, a large percentage of patients (37.8%) were lost to follow-up care. This led to the identification of multiple care gaps/barriers to ideal best practice. FLS programs use case finding strategies and address secondary fracture prevention. GHS HiROC's performance and initiation of drug therapy in this fracture patient population contrasts with GHS-PCP care's much lower rate of treatment, documenting the need for ongoing FLS care. Importantly, the results of this analysis have prompted the beginnings of GHS programmatic changes, designed to narrow the reported care gaps in this mature FLS.

  1. A bivariate contaminated binormal model for robust fitting of proper ROC curves to a pair of correlated, possibly degenerate, ROC datasets.

    Science.gov (United States)

    Zhai, Xuetong; Chakraborty, Dev P

    2017-06-01

    The objective was to design and implement a bivariate extension to the contaminated binormal model (CBM) to fit paired receiver operating characteristic (ROC) datasets-possibly degenerate-with proper ROC curves. Paired datasets yield two correlated ratings per case. Degenerate datasets have no interior operating points and proper ROC curves do not inappropriately cross the chance diagonal. The existing method, developed more than three decades ago utilizes a bivariate extension to the binormal model, implemented in CORROC2 software, which yields improper ROC curves and cannot fit degenerate datasets. CBM can fit proper ROC curves to unpaired (i.e., yielding one rating per case) and degenerate datasets, and there is a clear scientific need to extend it to handle paired datasets. In CBM, nondiseased cases are modeled by a probability density function (pdf) consisting of a unit variance peak centered at zero. Diseased cases are modeled with a mixture distribution whose pdf consists of two unit variance peaks, one centered at positive μ with integrated probability α, the mixing fraction parameter, corresponding to the fraction of diseased cases where the disease was visible to the radiologist, and one centered at zero, with integrated probability (1-α), corresponding to disease that was not visible. It is shown that: (a) for nondiseased cases the bivariate extension is a unit variances bivariate normal distribution centered at (0,0) with a specified correlation ρ 1 ; (b) for diseased cases the bivariate extension is a mixture distribution with four peaks, corresponding to disease not visible in either condition, disease visible in only one condition, contributing two peaks, and disease visible in both conditions. An expression for the likelihood function is derived. A maximum likelihood estimation (MLE) algorithm, CORCBM, was implemented in the R programming language that yields parameter estimates and the covariance matrix of the parameters, and other statistics

  2. Three-class ROC analysis--the equal error utility assumption and the optimality of three-class ROC surface using the ideal observer.

    Science.gov (United States)

    He, Xin; Frey, Eric C

    2006-08-01

    Previously, we have developed a decision model for three-class receiver operating characteristic (ROC) analysis based on decision theory. The proposed decision model maximizes the expected decision utility under the assumption that incorrect decisions have equal utilities under the same hypothesis (equal error utility assumption). This assumption reduced the dimensionality of the "general" three-class ROC analysis and provided a practical figure-of-merit to evaluate the three-class task performance. However, it also limits the generality of the resulting model because the equal error utility assumption will not apply for all clinical three-class decision tasks. The goal of this study was to investigate the optimality of the proposed three-class decision model with respect to several other decision criteria. In particular, besides the maximum expected utility (MEU) criterion used in the previous study, we investigated the maximum-correctness (MC) (or minimum-error), maximum likelihood (ML), and Nyman-Pearson (N-P) criteria. We found that by making assumptions for both MEU and N-P criteria, all decision criteria lead to the previously-proposed three-class decision model. As a result, this model maximizes the expected utility under the equal error utility assumption, maximizes the probability of making correct decisions, satisfies the N-P criterion in the sense that it maximizes the sensitivity of one class given the sensitivities of the other two classes, and the resulting ROC surface contains the maximum likelihood decision operating point. While the proposed three-class ROC analysis model is not optimal in the general sense due to the use of the equal error utility assumption, the range of criteria for which it is optimal increases its applicability for evaluating and comparing a range of diagnostic systems.

  3. Use of the ROC anchor in foot and ankle surgery. A retrospective study.

    Science.gov (United States)

    Kuwada, G T

    1999-05-01

    A retrospective study was conducted on the use of the ROC (Radial Osteo Compression) soft-tissue anchor in foot and ankle surgery. This article describes how the anchor is deployed, problematic aspects of using the anchor, and complications and success rates associated with the anchor in ankle stabilizations, posterior tibial tendon reconstruction, peroneus brevis tendon reconstruction after fracture of the base of the fifth metatarsal, and detachment and reattachment of the Achilles tendon. The ROC anchor consists of the anchor with nonabsorbable suture attached to the shaft, the deployment handle, and drill bits. The anchor and shaft are snapped into the deployment handle and inserted into the drill hole. Compression of the trigger deploys the anchor into the hole. The ROC anchor was found to be reliable, useful, and relatively easy to deploy, with outcomes similar to those of other soft-tissue anchors.

  4. ROC curve analyses of eyewitness identification decisions: An analysis of the recent debate.

    Science.gov (United States)

    Rotello, Caren M; Chen, Tina

    2016-01-01

    How should the accuracy of eyewitness identification decisions be measured, so that best practices for identification can be determined? This fundamental question is under intense debate. One side advocates for continued use of a traditional measure of identification accuracy, known as the diagnosticity ratio , whereas the other side argues that receiver operating characteristic curves (ROCs) should be used instead because diagnosticity is confounded with response bias. Diagnosticity proponents have offered several criticisms of ROCs, which we show are either false or irrelevant to the assessment of eyewitness accuracy. We also show that, like diagnosticity, Bayesian measures of identification accuracy confound response bias with witnesses' ability to discriminate guilty from innocent suspects. ROCs are an essential tool for distinguishing memory-based processes from decisional aspects of a response; simulations of different possible identification tasks and response strategies show that they offer important constraints on theory development.

  5. Exhibition; Image display agency

    International Nuclear Information System (INIS)

    Normazlin Ismail

    2008-01-01

    This article touches on the role of Malaysian Nuclear Agency as nuclear research institutions to promote, develop and encourage the peaceful uses of nuclear technology in its agricultural, medical, manufacturing, industrial, health and environment for the development of the country running successfully. Maturity of Malaysian Nuclear Agency in dealing with nuclear technology that are very competitive and globalization cannot be denied. On this basis Malaysian Nuclear Agency was given the responsibility to strengthen the nuclear technology in Malaysia. One way is through an exhibition featuring the research, discoveries and new technology products of the nuclear technology. Through this exhibition is to promote the nuclear technology and introduce the image of the agency in the public eye. This article also states a number of exhibits entered by the Malaysian Nuclear Agency and achievements during the last exhibition. Authors hope that the exhibition can be intensified further in the future.

  6. Fortescue reservoir development and reservoir studies

    Energy Technology Data Exchange (ETDEWEB)

    Henzell, S.T.; Hicks, G.J.; Horden, M.J.; Irrgang, H.R.; Janssen, E.J.; Kable, C.W.; Mitchell, R.A.H.; Morrell, N.W.; Palmer, I.D.; Seage, N.W.

    1985-03-01

    The Fortescue field in the Gippsland Basin, offshore southeastern Australia is being developed from two platforms (Fortescue A and Cobia A) by Esso Australia Ltd. (operator) and BHP Petroleum. The Fortescue reservoir is a stratigraphic trap at the top of the Latrobe Group of sediments. It overlies the western flank of the Halibut and Cobia fields and is separated from them by a non-net sequence of shales and coals which form a hydraulic barrier between the two systems. Development drilling into the Fortescue reservoir commenced in April 1983 with production coming onstream in May 1983. Fortescue, with booked reserves of 44 stock tank gigalitres (280 million stock tank barrels) of 43/sup 0/ API oil, is the seventh major oil reservoir to be developed in the offshore Gippsland Basin by Esso/BHP. In mid-1984, after drilling a total of 20 exploration and development wells, and after approximately one year of production, a detailed three-dimensional, two-phase reservoir simulation study was performed to examine the recovery efficiency, drainage patterns, pressure performance and production rate potential of the reservoir. The model was validated by history matching an extensive suite of Repeat Formation Test (RFT) pressure data. The results confirmed the reserves basis, and demonstrated that the ultimate oil recovery from the reservoir is not sensitive to production rate. This result is consistent with studies on other high quality Latrobe Group reservoirs in the Gippsland Basin which contain undersaturated crudes and receive very strong water drive from the Basin-wide aquifer system. With the development of the simulation model during the development phase, it has been possible to more accurately define the optimal well pattern for the remainder of the development.

  7. El rocío y el turismo de peregrinación

    Directory of Open Access Journals (Sweden)

    Águeda Villa Díaz

    2006-01-01

    Full Text Available La palabra Rocío está llena de significados: una virgen, una romería y una aldea —vecinas de la marisma del Guadalquivir— bautizadas por un fenómeno microclimático, como es la diaria y fecunda presencia de agua en su mínima expresión —las gotas de rocío—. Pero este nombre evoca, sobre todo, a la devoción a Nuestra Señora del Rocío —Patrona de Almonte— y a su anual romería de Pentecostés —el Rocío Grande—. Esta romería ha conocido una gran expansión en los últimos cincuenta años, atrayendo peregrinos de puntos cada vez más lejanos, pero su origen es muy antiguo y siempre se ha desarrollado asociada a la aldea. En su imparable proceso de crecimiento, aquella aldea y sus rituales festivos muestran una rápida evolución —adaptable a las nuevas circunstancias— que no desdeña la incorporación de nuevos y dispares elementos, que las modifican sensible y profundamente. De manera que, el Rocío conforma, actualmente, una realidad espacial, social, económica, cultural y simbólica en ebullición. La estrecha vinculación de la aldea y las rutas de peregrinación con los espacios protegidos de Doñana relacionan El Rocío con las políticas de conservación de la naturaleza.

  8. Overestimation of test performance by ROC analysis: Effect of small sample size

    International Nuclear Information System (INIS)

    Seeley, G.W.; Borgstrom, M.C.; Patton, D.D.; Myers, K.J.; Barrett, H.H.

    1984-01-01

    New imaging systems are often observer-rated by ROC techniques. For practical reasons the number of different images, or sample size (SS), is kept small. Any systematic bias due to small SS would bias system evaluation. The authors set about to determine whether the area under the ROC curve (AUC) would be systematically biased by small SS. Monte Carlo techniques were used to simulate observer performance in distinguishing signal (SN) from noise (N) on a 6-point scale; P(SN) = P(N) = .5. Four sample sizes (15, 25, 50 and 100 each of SN and N), three ROC slopes (0.8, 1.0 and 1.25), and three intercepts (0.8, 1.0 and 1.25) were considered. In each of the 36 combinations of SS, slope and intercept, 2000 runs were simulated. Results showed a systematic bias: the observed AUC exceeded the expected AUC in every one of the 36 combinations for all sample sizes, with the smallest sample sizes having the largest bias. This suggests that evaluations of imaging systems using ROC curves based on small sample size systematically overestimate system performance. The effect is consistent but subtle (maximum 10% of AUC standard deviation), and is probably masked by the s.d. in most practical settings. Although there is a statistically significant effect (F = 33.34, P<0.0001) due to sample size, none was found for either the ROC curve slope or intercept. Overestimation of test performance by small SS seems to be an inherent characteristic of the ROC technique that has not previously been described

  9. ROC-ing along: Evaluation and interpretation of receiver operating characteristic curves.

    Science.gov (United States)

    Carter, Jane V; Pan, Jianmin; Rai, Shesh N; Galandiuk, Susan

    2016-06-01

    It is vital for clinicians to understand and interpret correctly medical statistics as used in clinical studies. In this review, we address current issues and focus on delivering a simple, yet comprehensive, explanation of common research methodology involving receiver operating characteristic (ROC) curves. ROC curves are used most commonly in medicine as a means of evaluating diagnostic tests. Sample data from a plasma test for the diagnosis of colorectal cancer were used to generate a prediction model. These are actual, unpublished data that have been used to describe the calculation of sensitivity, specificity, positive predictive and negative predictive values, and accuracy. The ROC curves were generated to determine the accuracy of this plasma test. These curves are generated by plotting the sensitivity (true-positive rate) on the y axis and 1 - specificity (false-positive rate) on the x axis. Curves that approach closest to the coordinate (x = 0, y = 1) are more highly predictive, whereas ROC curves that lie close to the line of equality indicate that the result is no better than that obtained by chance. The optimum sensitivity and specificity can be determined from the graph as the point where the minimum distance line crosses the ROC curve. This point corresponds to the Youden index (J), a function of sensitivity and specificity used commonly to rate diagnostic tests. The area under the curve is used to quantify the overall ability of a test to discriminate between 2 outcomes. By following these simple guidelines, interpretation of ROC curves will be less difficult and they can then be interpreted more reliably when writing, reviewing, or analyzing scientific papers. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Transport of reservoir fines

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander; Stenby, Erling Halfdan

    Modeling transport of reservoir fines is of great importance for evaluating the damage of production wells and infectivity decline. The conventional methodology accounts for neither the formation heterogeneity around the wells nor the reservoir fines’ heterogeneity. We have developed an integral...... dispersion equation in modeling the transport and the deposition of reservoir fines. It successfully predicts the unsymmetrical concentration profiles and the hyperexponential deposition in experiments....

  11. Multi-data reservoir history matching for enhanced reservoir forecasting and uncertainty quantification

    KAUST Repository

    Katterbauer, Klemens

    2015-04-01

    Reservoir simulations and history matching are critical for fine-tuning reservoir production strategies, improving understanding of the subsurface formation, and forecasting remaining reserves. Production data have long been incorporated for adjusting reservoir parameters. However, the sparse spatial sampling of this data set has posed a significant challenge for efficiently reducing uncertainty of reservoir parameters. Seismic, electromagnetic, gravity and InSAR techniques have found widespread applications in enhancing exploration for oil and gas and monitoring reservoirs. These data have however been interpreted and analyzed mostly separately, rarely exploiting the synergy effects that could result from combining them. We present a multi-data ensemble Kalman filter-based history matching framework for the simultaneous incorporation of various reservoir data such as seismic, electromagnetics, gravimetry and InSAR for best possible characterization of the reservoir formation. We apply an ensemble-based sensitivity method to evaluate the impact of each observation on the estimated reservoir parameters. Numerical experiments for different test cases demonstrate considerable matching enhancements when integrating all data sets in the history matching process. Results from the sensitivity analysis further suggest that electromagnetic data exhibit the strongest impact on the matching enhancements due to their strong differentiation between water fronts and hydrocarbons in the test cases.

  12. Recent developments in the ROCS/MC code for retrieving local power information in coarse-mesh reactor analysis

    International Nuclear Information System (INIS)

    Grill, S.F.; Jonsson, A.; Crump, M.W.

    1983-01-01

    The inclusion of 3-D effects in PWR analysis is necessary for accurate predictions of reactivity, power distributions, and reactivity coefficients. The ROCS/MC code system has been developed by Combustion Engineering to provide 3-D coarse mesh analysis (ROCS) with the capability to retrieve local information on flux, power and burnup (MC). A review of the finite difference representation of the MC diffusion equation, along with recent improvements to the ROCS/MC system are presented. These improvements include the implementation if fine mesh radial boundary conditions and internal calculation of coarse mesh boundary conditions, generalization of the imbedded calculation to account for the local neighboring environment, and the automation of ROCS/MC links to C-E's code system for in-core power distribution monitoring and core-follow analysis. The results of the ROCS/MC verification program are described and show good agreement with C-E's ROCS/PDQ based methodologies

  13. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING

    Energy Technology Data Exchange (ETDEWEB)

    Stephen C. Ruppel

    2005-02-01

    Despite declining production rates, existing reservoirs in the US contain large quantities of remaining oil and gas that constitute a huge target for improved diagnosis and imaging of reservoir properties. The resource target is especially large in carbonate reservoirs, where conventional data and methodologies are normally insufficient to resolve critical scales of reservoir heterogeneity. The objectives of the research described in this report were to develop and test such methodologies for improved imaging, measurement, modeling, and prediction of reservoir properties in carbonate hydrocarbon reservoirs. The focus of the study is the Permian-age Fullerton Clear Fork reservoir of the Permian Basin of West Texas. This reservoir is an especially appropriate choice considering (a) the Permian Basin is the largest oil-bearing basin in the US, and (b) as a play, Clear Fork reservoirs have exhibited the lowest recovery efficiencies of all carbonate reservoirs in the Permian Basin.

  14. Progress in evaluation of human observer visual detection performance using the ROC curve approach

    International Nuclear Information System (INIS)

    Metz, C.E.; Starr, S.J.; Lusted, L.B.; Rossmann, K.

    1976-01-01

    The ROC approach to analysis of human observer detection performance as playing a key role in elucidation the relationships among the physical parameters of an imaging operation, the ability of a human observer to use the image to make decisions regarding the state of health or disease in a medical diagnostic situation, and the medical and social utility of those decisions, was studied. The conventional ROC curve describing observer performance in simple detection tasks can be used to predict observer performance in complex detection tasks. The conventional ROC curve thus provides a description of observer detection performance which is useful in situations more relevant clinically than those for which it is measured. Similar predictions regarding observer performance in identification and recognition tasks are currently being sought. The ROC curve can be used to relate signal detectability to various measures of the diagnostic and social benefit derived from a medical imaging procedure. These relationships provide a means for assessing the relative desirability of alternative diagnostic techniques and can be used to evaluate combinations of diagnostic studies

  15. Separating Mnemonic Process From Participant and Item Effects in the Assessment of ROC Asymmetries

    NARCIS (Netherlands)

    Pratte, Michael S.; Rouder, Jeffrey N.; Morey, Richard D.

    One of the most influential findings in the study of recognition memory is that receiver operating characteristic (ROC) curves are asymmetric about the negative diagonal. This result has led to the rejection of the equal-variance signal detection model of recognition memory and has provided

  16. Separating Mnemonic Process from Participant and Item Effects in the Assessment of ROC Asymmetries

    Science.gov (United States)

    Pratte, Michael S.; Rouder, Jeffrey N.; Morey, Richard D.

    2010-01-01

    One of the most influential findings in the study of recognition memory is that receiver operating characteristic (ROC) curves are asymmetric about the negative diagonal. This result has led to the rejection of the equal-variance signal detection model of recognition memory and has provided motivation for more complex models, such as the…

  17. Life-Long Cyberlearning System: A Pilot Project for the "Learning Society" in the ROC.

    Science.gov (United States)

    Han, Huei-Wen; Wang, Yen-Chao

    1999-01-01

    Provides an overview of the implementation of lifelong learning in Taiwan, Republic of China (ROC) as part of its educational reform policy and describes a pilot project, the Lifelong Cyberlearning System. Highlights include planning architecture, Web-based learning technology, professional education, industrial and corporate assistance, and…

  18. An ROC-type measure of diagnostic accuracy when the gold standard is continuous-scale.

    Science.gov (United States)

    Obuchowski, Nancy A

    2006-02-15

    ROC curves and summary measures of accuracy derived from them, such as the area under the ROC curve, have become the standard for describing and comparing the accuracy of diagnostic tests. Methods for estimating ROC curves rely on the existence of a gold standard which dichotomizes patients into disease present or absent. There are, however, many examples of diagnostic tests whose gold standards are not binary-scale, but rather continuous-scale. Unnatural dichotomization of these gold standards leads to bias and inconsistency in estimates of diagnostic accuracy. In this paper, we propose a non-parametric estimator of diagnostic test accuracy which does not require dichotomization of the gold standard. This estimator has an interpretation analogous to the area under the ROC curve. We propose a confidence interval for test accuracy and a statistical test for comparing accuracies of tests from paired designs. We compare the performance (i.e. CI coverage, type I error rate, power) of the proposed methods with several alternatives. An example is presented where the accuracies of two quick blood tests for measuring serum iron concentrations are estimated and compared.

  19. Design of a receiver operating characteristic (ROC) study of 10:1 lossy image compression

    Science.gov (United States)

    Collins, Cary A.; Lane, David; Frank, Mark S.; Hardy, Michael E.; Haynor, David R.; Smith, Donald V.; Parker, James E.; Bender, Gregory N.; Kim, Yongmin

    1994-04-01

    The digital archiving system at Madigan Army Medical Center (MAMC) uses a 10:1 lossy data compression algorithm for most forms of computed radiography. A systematic study on the potential effect of lossy image compression on patient care has been initiated with a series of studies focused on specific diagnostic tasks. The studies are based upon the receiver operating characteristic (ROC) method of analysis for diagnostic systems. The null hypothesis is that observer performance with approximately 10:1 compressed and decompressed images is not different from using original, uncompressed images for detecting subtle pathologic findings seen on computed radiographs of bone, chest, or abdomen, when viewed on a high-resolution monitor. Our design involves collecting cases from eight pathologic categories. Truth is determined by committee using confirmatory studies performed during routine clinical practice whenever possible. Software has been developed to aid in case collection and to allow reading of the cases for the study using stand-alone Siemens Litebox workstations. Data analysis uses two methods, ROC analysis and free-response ROC (FROC) methods. This study will be one of the largest ROC/FROC studies of its kind and could benefit clinical radiology practice using PACS technology. The study design and results from a pilot FROC study are presented.

  20. Item Strength Influences Source Confidence and Alters Source Memory zROC Slopes

    Science.gov (United States)

    Starns, Jeffrey J.; Ksander, John C.

    2016-01-01

    Increasing the number of study trials creates a crossover pattern in source memory zROC slopes; that is, the slope is either below or above 1 depending on which source receives stronger learning. This pattern can be produced if additional learning affects memory processes such as the relative contribution of recollection and familiarity to source…

  1. Theoretical vs. empirical discriminability: the application of ROC methods to eyewitness identification.

    Science.gov (United States)

    Wixted, John T; Mickes, Laura

    2018-01-01

    Receiver operating characteristic (ROC) analysis was introduced to the field of eyewitness identification 5 years ago. Since that time, it has been both influential and controversial, and the debate has raised an issue about measuring discriminability that is rarely considered. The issue concerns the distinction between empirical discriminability (measured by area under the ROC curve) vs. underlying/theoretical discriminability (measured by d' or variants of it). Under most circumstances, the two measures will agree about a difference between two conditions in terms of discriminability. However, it is possible for them to disagree, and that fact can lead to confusion about which condition actually yields higher discriminability. For example, if the two conditions have implications for real-world practice (e.g., a comparison of competing lineup formats), should a policymaker rely on the area-under-the-curve measure or the theory-based measure? Here, we illustrate the fact that a given empirical ROC yields as many underlying discriminability measures as there are theories that one is willing to take seriously. No matter which theory is correct, for practical purposes, the singular area-under-the-curve measure best identifies the diagnostically superior procedure. For that reason, area under the ROC curve informs policy in a way that underlying theoretical discriminability never can. At the same time, theoretical measures of discriminability are equally important, but for a different reason. Without an adequate theoretical understanding of the relevant task, the field will be in no position to enhance empirical discriminability.

  2. Software for illustrative presentation of basic clinical characteristics of laboratory tests--GraphROC for Windows.

    Science.gov (United States)

    Kairisto, V; Poola, A

    1995-01-01

    GraphROC for Windows is a program for clinical test evaluation. It was designed for the handling of large datasets obtained from clinical laboratory databases. In the user interface, graphical and numerical presentations are combined. For simplicity, numerical data is not shown unless requested. Relevant numbers can be "picked up" from the graph by simple mouse operations. Reference distributions can be displayed by using automatically optimized bin widths. Any percentile of the distribution with corresponding confidence limits can be chosen for display. In sensitivity-specificity analysis, both illness- and health-related distributions are shown in the same graph. The following data for any cutoff limit can be shown in a separate click window: clinical sensitivity and specificity with corresponding confidence limits, positive and negative likelihood ratios, positive and negative predictive values and efficiency. Predictive values and clinical efficiency of the cutoff limit can be updated for any prior probability of disease. Receiver Operating Characteristics (ROC) curves can be generated and combined into the same graph for comparison of several different tests. The area under the curve with corresponding confidence interval is calculated for each ROC curve. Numerical results of analyses and graphs can be printed or exported to other Microsoft Windows programs. GraphROC for Windows also employs a new method, developed by us, for the indirect estimation of health-related limits and change limits from mixed distributions of clinical laboratory data.

  3. Face recognition in schizophrenia: do individual and average ROCs tell the same story?

    Science.gov (United States)

    Tiberghien, Guy; Martin, Clara; Baudouin, Jean-Yves; Franck, Nicolas; Guillaume, Fabrice; Huron, Caroline

    2015-01-01

    Many studies have shown that recollection process is impaired in patients with schizophrenia, whereas familiarity is generally spared. However, in these studies, the Receiver Operating Characteristic (ROC) presented is average ROC likely to mask individual differences. In the present study using a face-recognition task, we computed the individual ROC of patients with schizophrenia and control participants. Each group was divided into two subgroups on the basis of the type of recognition processes implemented: recognition based on familiarity only and recognition based on familiarity and recollection. The recognition performance of the schizophrenia patients was below that of the control participants only when recognition was based solely on familiarity. For the familiarity-alone patients, the score obtained on the Scale for the Assessment of Positive Symptoms (SAPS) was correlated with the variance of the old-face familiarity. For the familiarity-recollection patients, the score obtained on the Scale for the Assessment of Negative Symptoms (SANS) was correlated with the decision criterion and with the old-face recollection probability. These results show that one cannot ascribe the impaired recognition observed in patients with schizophrenia to a recollection deficit alone. These results show that individual ROC can be used to distinguish between subtypes of schizophrenia and could serve as a basis for setting up specific cognitive remediation therapy for individuals with schizophrenia.

  4. Reservoir Engineering Management Program

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.H.; Schwarz, W.J.

    1977-12-14

    The Reservoir Engineering Management Program being conducted at Lawrence Berkeley Laboratory includes two major tasks: 1) the continuation of support to geothermal reservoir engineering related work, started under the NSF-RANN program and transferred to ERDA at the time of its formation; 2) the development and subsequent implementation of a broad plan for support of research in topics related to the exploitation of geothermal reservoirs. This plan is now known as the GREMP plan. Both the NSF-RANN legacies and GREMP are in direct support of the DOE/DGE mission in general and the goals of the Resource and Technology/Resource Exploitation and Assessment Branch in particular. These goals are to determine the magnitude and distribution of geothermal resources and reduce risk in their exploitation through improved understanding of generically different reservoir types. These goals are to be accomplished by: 1) the creation of a large data base about geothermal reservoirs, 2) improved tools and methods for gathering data on geothermal reservoirs, and 3) modeling of reservoirs and utilization options. The NSF legacies are more research and training oriented, and the GREMP is geared primarily to the practical development of the geothermal reservoirs. 2 tabs., 3 figs.

  5. Council Chamber exhibition

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    To complete the revamp of CERN’s Council Chamber, a new exhibition is being installed just in time for the June Council meetings.   Panels will showcase highlights of CERN’s history, using some of the content prepared for the exhibitions marking 50 years of the PS, which were displayed in the main building last November. The previous photo exhibition in the Council Chamber stopped at the 1970s. To avoid the new panels becoming quickly out of date, photos are grouped together around specific infrastructures, rather than following a classic time-line. “We have put the focus on the accelerators – the world-class facilities that CERN has been offering researchers over the years, from the well-known large colliders to the lesser-known smaller facilities,” says Emma Sanders, who worked on the content. The new exhibition will be featured in a future issue of the Bulletin with photos and an interview with Fabienne Marcastel, designer of the exhibit...

  6. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

    An exhibition of plastic arts and two evenings of performances by sound and visual artists as part of CERN's 50th anniversary celebrations. Fifty candles for CERN, an international laboratory renowned for fundamental research, is a cause for celebration. Since March this year, Geneva and neighbouring parts of France have been the venues for a wealth of small and large-scale events, which will continue until November. Given CERN's location in the commune of Meyrin, the ForuMeyrin is hosting exhibitions of plastic arts and performances entitled: Accelerated Particles. Several works will be exhibited and performed in two 'salons'. Salon des matières: An exhibition of plastic arts From Tues 12 October to Wed 3 November 2004 Tuesdays to Fridays: 16:00 to 19:00 Saturdays: 14:00 to 18:00 Exhibition open late on performance nights, entrance free Salon des particules: Musical and visual performances Tues 12 and Mon 25 October from 20:00 to 23:00 Preview evening for both events: Tues 12 October from 18:...

  7. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

    http://www.cern.ch/cern50/ An exhibition of plastic arts and two evenings of performances by sound and visual artists as part of CERN's fiftieth anniversary celebrations. The fiftieth anniversary of a world famous organization like CERN, an international laboratory specializing in fundamental research, is a cause for celebration. Since March this year, Geneva and neighbouring parts of France have been the venues for a wealth of small and large-scale events, which will continue until November. Given CERN's location in the commune of Meyrin, the ForuMeyrin is hosting two "salons" consisting of an exhibition of plastic arts and evenings of music and visual arts performances with the collective title of "Accelerated Particles". Several works will be exhibited and performed. Salon des matières: An exhibition of plastic arts Until Wednesday 3 November 2004. Tuesdays to Fridays: 4.00 p.m. to 7.00 p.m. Saturdays: 2.00 p.m. to 6.00 p.m. Doors open late on the evening of the performances. Salon des ...

  8. Sediment management for reservoir

    International Nuclear Information System (INIS)

    Rahman, A.

    2005-01-01

    All natural lakes and reservoirs whether on rivers, tributaries or off channel storages are doomed to be sited up. Pakistan has two major reservoirs of Tarbela and Managla and shallow lake created by Chashma Barrage. Tarbela and Mangla Lakes are losing their capacities ever since first impounding, Tarbela since 1974 and Mangla since 1967. Tarbela Reservoir receives average annual flow of about 62 MAF and sediment deposits of 0.11 MAF whereas Mangla gets about 23 MAF of average annual flows and is losing its storage at the rate of average 34,000 MAF annually. The loss of storage is a great concern and studies for Tarbela were carried out by TAMS and Wallingford to sustain its capacity whereas no study has been done for Mangla as yet except as part of study for Raised Mangla, which is only desk work. Delta of Tarbala reservoir has advanced to about 6.59 miles (Pivot Point) from power intakes. In case of liquefaction of delta by tremor as low as 0.12g peak ground acceleration the power tunnels I, 2 and 3 will be blocked. Minimum Pool of reservoir is being raised so as to check the advance of delta. Mangla delta will follow the trend of Tarbela. Tarbela has vast amount of data as reservoir is surveyed every year, whereas Mangla Reservoir survey was done at five-year interval, which has now been proposed .to be reduced to three-year interval. In addition suspended sediment sampling of inflow streams is being done by Surface Water Hydrology Project of WAPDA as also some bed load sampling. The problem of Chasma Reservoir has also been highlighted, as it is being indiscriminately being filled up and drawdown several times a year without regard to its reaction to this treatment. The Sediment Management of these reservoirs is essential and the paper discusses pros and cons of various alternatives. (author)

  9. Optimising reservoir operation

    DEFF Research Database (Denmark)

    Ngo, Long le

    Anvendelse af optimeringsteknik til drift af reservoirer er blevet et væsentligt element i vandressource-planlægning og -forvaltning. Traditionelt har reservoirer været styret af heuristiske procedurer for udtag af vand, suppleret i en vis udstrækning af subjektive beslutninger. Udnyttelse af...... reservoirer involverer en lang række interessenter med meget forskellige formål (f.eks. kunstig vanding, vandkraft, vandforsyning mv.), og optimeringsteknik kan langt bedre lede frem til afbalancerede løsninger af de ofte modstridende interesser. Afhandlingen foreslår en række tiltag, hvormed traditionelle...

  10. International Space Station exhibit

    Science.gov (United States)

    2000-01-01

    The International Space Station (ISS) exhibit in StenniSphere at John C. Stennis Space Center in Hancock County, Miss., gives visitors an up-close look at the largest international peacetime project in history. Step inside a module of the ISS and glimpse how astronauts will live and work in space. Currently, 16 countries contribute resources and hardware to the ISS. When complete, the orbiting research facility will be larger than a football field.

  11. Upcycling CERN Exhibitions

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    Summer is coming - and with it, a new Microcosm exhibition showcasing CERN (see here). But while the new exhibit is preparing to enchant visitors, many have been asking about the site's former content. Will it simply be out with the old and in with the new? Not as such!   The plasma ball from Microcosm is now on display at the LHCb site. As Microcosm's new content is moving in, its old content is moving up. From LHCb to IdeaSquare, former Microcosm displays and objects are being installed across the CERN site. "Microcosm featured many elements that were well suited to life outside of the exhibition," says Emma Sanders, Microcosm project leader in the EDU group. "We didn't want this popular content to go to waste, and so set out to find them new homes across CERN." The LHCb experiment has received a number of Microcosm favourites, including the Rutherford experiment, the cosmic ray display and the Thomson experiment. "We&...

  12. Online Exhibits & Concept Maps

    Science.gov (United States)

    Douma, M.

    2009-12-01

    Presenting the complexity of geosciences to the public via the Internet poses a number of challenges. For example, utilizing various - and sometimes redundant - Web 2.0 tools can quickly devour limited time. Do you tweet? Do you write press releases? Do you create an exhibit or concept map? The presentation will provide participants with a context for utilizing Web 2.0 tools by briefly highlighting methods of online scientific communication across several dimensions. It will address issues of: * breadth and depth (e.g. from narrow topics to well-rounded views), * presentation methods (e.g. from text to multimedia, from momentary to enduring), * sources and audiences (e.g. for experts or for the public, content developed by producers to that developed by users), * content display (e.g. from linear to non-linear, from instructive to entertaining), * barriers to entry (e.g. from an incumbent advantage to neophyte accessible, from amateur to professional), * cost and reach (e.g. from cheap to expensive), and * impact (e.g. the amount learned, from anonymity to brand awareness). Against this backdrop, the presentation will provide an overview of two methods of online information dissemination, exhibits and concept maps, using the WebExhibits online museum (www.webexhibits.org) and SpicyNodes information visualization tool (www.spicynodes.org) as examples, with tips on how geoscientists can use either to communicate their science. Richly interactive online exhibits can serve to engage a large audience, appeal to visitors with multiple learning styles, prompt exploration and discovery, and present a topic’s breadth and depth. WebExhibits, which was among the first online museums, delivers interactive information, virtual experiments, and hands-on activities to the public. While large, multidisciplinary exhibits on topics like “Color Vision and Art” or “Calendars Through the Ages” require teams of scholars, user interface experts, professional writers and editors

  13. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.

    1995-02-01

    This final report summarizes the progress during the three years of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description; (ii) scale-up procedures; (iii) outcrop investigation. The first section describes the methods by which a reservoir can be described in three dimensions. The next step in reservoir description is to scale up reservoir properties for flow simulation. The second section addresses the issue of scale-up of reservoir properties once the spatial descriptions of properties are created. The last section describes the investigation of an outcrop.

  14. ROC analysis of benefit and limitation in radiotherapy for cancer of the oral cavity

    International Nuclear Information System (INIS)

    Maciejewski, B.; Zajusz, A.

    1993-01-01

    The ROC (receiver operating characteristic) analysis of optimization of radiation treatment of cancer of oral cavity was carried out. Material of 210 patients with squamous cell carcinoma of the oral cavity was included into the study. Based on dose-response curves for tumor and late mucosal reactions, iso-utility curves and optimal k values were estimated. Optimal k values decreased from 0.792 to 0.584 with extension of overall treatment time from 35 to 49 days. This may suggest that the planning of additional dose to compensate tumor clonogens repopulation during prolonged treatment does not improve the therapeutic gain in radiotherapy for cancer of the oral cavity. The ROC is a useful model to estimate the optimal radiation treatment for a given tumor because it is independent of any arbitrary consensus or theoretical assumption. (author) 1 tab., 3 figs., 5 refs

  15. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    OpenAIRE

    Shams Bilal; Yao Jun; Zhang Kai; Zhang Lei

    2017-01-01

    Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large...

  16. Diagnostic accuracy of quantitative 99mTc-MIBI scintimammography according to ROC curve analysis

    International Nuclear Information System (INIS)

    Kim, J. H.; Lee, H. K.; Seo, J. W.; Cho, N. S.; Cha, K. H.; Lee, T. H.

    1998-01-01

    99mTc-sestamibi scintimammography (SMM) has been shown to be a useful diagnostic test in the detection of breast cancer and the receiver operating characteristic (ROC) curve analysis provides detailed information of a diagnostic test. The purpose of this study was to evaluate the feasibility and efficacy of quantitative indices of SMM in the detection of malignant breast lesions according to ROC analysis. Prone anterior, lateral planar and supine SPECT imagings were performed on 75 female patients (mean age=43.4 yr) with breast mass (size≥0.8cm) after intravenous injection of 20-30 mCi 99mTc-sestamibi. 45 Malignant (Invasive ductal ca(36), Inv lobular ca(5), Inv duc + lob (1), Inv tubular ca (3)) and 30 benign (fibroadenoma (13), fib cyst(12), Fat necrosis(3), papilloma(1), paraffinoma (1)) lesions were histologically proven. Data were analyzed by creating three regions of interest (ROIs) over designated areas: lesion, normal breast and right chest wall. Lesion to normal (L/NL) and lesion to chest wall (L/CW) ratios were calculated for each patient both on the planar and SPECT. The area under the ROC curve (AUC) was calculated and compared among four semiquantitative indices and an average scintimammographic index (SMM(mean)) from arithmatic mean. ROC curve analysis revealed planar L/N, SPECT L/N and L/CW ratios provide comparable better diagnostic accuracies for detection of breast cancer than planar L/CW ratio (p<0.05), respectively. For quantitative SMM of 75 lesions, malignancy rate was 60%, and Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value and Accuracy were 0.78, 0.77, 0.84, 0.72 and 0.77, respectively. Quantitative SMM is an useful objective method for differentiating malignant from benign breast lesions

  17. Diagnostic accuracy of the MMPI-2 with the Mexican criminal personality: The ROC curve analysis

    OpenAIRE

    Ampudia Rueda, Amada; Sánchez Crespo, Guadalupe; Jiménez Gómez, Fernando 

    2016-01-01

    The objective of this study is to assess the diagnostic accuracy of the personality of the Mexican criminal with the Minnesota Multiphasic Personality Inventory-2 (MMPI-2). The inventory was administered to 1,740 Mexican participants of which 870 (728 male and 142 female) are prison inmates, processed and/or sentenced for various crimes from various prisons in Mexico City, and the other 870 participants (728 male and 142 female) are not prison inmates. The ROC (Receiver Operating Characterist...

  18. Diagnostic accuracy of quantitative 99mTc-MIBI scintimammography according to ROC curve analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. H.; Lee, H. K.; Seo, J. W.; Cho, N. S.; Cha, K. H.; Lee, T. H. [Gachon Medical College, Gil Medical Center, Inchon (Korea, Republic of)

    1998-07-01

    99mTc-sestamibi scintimammography (SMM) has been shown to be a useful diagnostic test in the detection of breast cancer and the receiver operating characteristic (ROC) curve analysis provides detailed information of a diagnostic test. The purpose of this study was to evaluate the feasibility and efficacy of quantitative indices of SMM in the detection of malignant breast lesions according to ROC analysis. Prone anterior, lateral planar and supine SPECT imagings were performed on 75 female patients (mean age=43.4 yr) with breast mass (size{>=}0.8cm) after intravenous injection of 20-30 mCi 99mTc-sestamibi. 45 Malignant (Invasive ductal ca(36), Inv lobular ca(5), Inv duc + lob (1), Inv tubular ca (3)) and 30 benign (fibroadenoma (13), fib cyst(12), Fat necrosis(3), papilloma(1), paraffinoma (1)) lesions were histologically proven. Data were analyzed by creating three regions of interest (ROIs) over designated areas: lesion, normal breast and right chest wall. Lesion to normal (L/NL) and lesion to chest wall (L/CW) ratios were calculated for each patient both on the planar and SPECT. The area under the ROC curve (AUC) was calculated and compared among four semiquantitative indices and an average scintimammographic index (SMM(mean)) from arithmatic mean. ROC curve analysis revealed planar L/N, SPECT L/N and L/CW ratios provide comparable better diagnostic accuracies for detection of breast cancer than planar L/CW ratio (p<0.05), respectively. For quantitative SMM of 75 lesions, malignancy rate was 60%, and Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value and Accuracy were 0.78, 0.77, 0.84, 0.72 and 0.77, respectively. Quantitative SMM is an useful objective method for differentiating malignant from benign breast lesions.

  19. Spatial resolution requirements in digital radiography of scaphoid fractures. An ROC analysis

    International Nuclear Information System (INIS)

    Jonsson, A.; Laurin, S.; Karner, G.; Herrlin, K.; Hochbergs, P.; Jonsson, K.; Rudling, O.; Sandstroem, S.; Sloth, M.; Svahn, G.; Pettersson, H.

    1996-01-01

    Purpose: To investigate the spatial resolution requirements in digital radiography of scaphoid fractures. Material and Methods: Included in the study were 60 scaphoid radiographs with and 60 without fractures of the scaphoid bone. The film-screen images were digitized using pixel sizes of 115, 170, and 340 μm along with 170 μm with a 10:1 wavelet compression. The digital images were displayed on a 1280 x 1024 x 8 bits monitor, and 5 observers evaluated the images in 5 randomized sessions. The results for each pixel size were then compared to the film-screen images by ROC analysis. Results: The mean area under the ROC curves was larger for the film-screen images than for the digital images at all resolutions. However, this difference was not significant when the areas under the ROC curves for the film-screen images were compared to the digital images of 115, 170, and 170 μm with 10:1 compression. There was a significant difference for the 340-μm pixel size in favour of the film-screen images. The mean ROC curves for the digital images were very similar for the 115 and 170 μm pixel sizes, although slightly better for 115 μm. At 170 μm, the compression seemed to have a relatively small negative effect on the diagnostic performance; the deterioration was greater when the pixel size was increased to 340 μm. There was no obvious correlation between diagnostic performance and the experience of the observers in using workstations. Conclusions: The pixel size of 170 μm is adequate for the detection of subtle fractures, even after wavelet compression by a ratio of 10:1. (orig.)

  20. Statistical properties of a utility measure of observer performance compared to area under the ROC curve

    Science.gov (United States)

    Abbey, Craig K.; Samuelson, Frank W.; Gallas, Brandon D.; Boone, John M.; Niklason, Loren T.

    2013-03-01

    The receiver operating characteristic (ROC) curve has become a common tool for evaluating diagnostic imaging technologies, and the primary endpoint of such evaluations is the area under the curve (AUC), which integrates sensitivity over the entire false positive range. An alternative figure of merit for ROC studies is expected utility (EU), which focuses on the relevant region of the ROC curve as defined by disease prevalence and the relative utility of the task. However if this measure is to be used, it must also have desirable statistical properties keep the burden of observer performance studies as low as possible. Here, we evaluate effect size and variability for EU and AUC. We use two observer performance studies recently submitted to the FDA to compare the EU and AUC endpoints. The studies were conducted using the multi-reader multi-case methodology in which all readers score all cases in all modalities. ROC curves from the study were used to generate both the AUC and EU values for each reader and modality. The EU measure was computed assuming an iso-utility slope of 1.03. We find mean effect sizes, the reader averaged difference between modalities, to be roughly 2.0 times as big for EU as AUC. The standard deviation across readers is roughly 1.4 times as large, suggesting better statistical properties for the EU endpoint. In a simple power analysis of paired comparison across readers, the utility measure required 36% fewer readers on average to achieve 80% statistical power compared to AUC.

  1. Optimization of restricted ROC surfaces in three-class classification tasks.

    Science.gov (United States)

    Edwards, Darrin C; Metz, Charles E

    2007-10-01

    We have shown previously that an N-class ideal observer achieves the optimal receiver operating characteristic (ROC) hypersurface in a Neyman-Pearson sense. Due to the inherent complexity of evaluating observer performance even in a three-class classification task, some researchers have suggested a generally incomplete but more tractable evaluation in terms of a surface, plotting only the three "sensitivities." More generally, one can evaluate observer performance with a single sensitivity or misclassification probability as a function of two linear combinations of sensitivities or misclassification probabilities. We analyzed four such formulations including the "sensitivity" surface. In each case, we applied the Neyman-Pearson criterion to find the observer which achieves optimal performance with respect to each given set of "performance description variables" under consideration. In the unrestricted case, optimization with respect to the Neyman-Pearson criterion yields the ideal observer, as does maximization of the observer's expected utility. Moreover, during our consideration of the restricted cases, we found that the two optimization methods do not merely yield the same observer, but are in fact completely equivalent in a mathematical sense. Thus, for a wide variety of observers which maximize performance with respect to a restricted ROC surface in the Neyman-Pearson sense, that ROC surface can also be shown to provide a complete description of the observer's performance in an expected utility sense.

  2. iROCS: Integrated accident management framework for coping with beyond-design-basis external events

    International Nuclear Information System (INIS)

    Kim, Jaewhan; Park, Soo-Yong; Ahn, Kwang-Il; Yang, Joon-Eon

    2016-01-01

    Highlights: • An integrated mitigating strategy to cope with extreme external events, iROCS, is proposed. • The strategy aims to preserve the integrity of the reactor vessel as well as core cooling. • A case study for an extreme damage state is performed to assess the effectiveness and feasibility of candidate mitigation strategies under an extreme event. - Abstract: The Fukushima Daiichi accident induced by the Great East Japan earthquake and tsunami on March 11, 2011, poses a new challenge to the nuclear society, especially from an accident management viewpoint. This paper presents a new accident management framework called an integrated, RObust Coping Strategy (iROCS) to cope with beyond-design-basis external events (BDBEEs). The iROCS approach is characterized by classification of various plant damage conditions (PDCs) that might be impacted by BDBEEs and corresponding integrated coping strategies for each of PDCs, aiming to maintain and restore core cooling (i.e., to prevent core damage) and to maintain the integrity of the reactor pressure vessel if it is judged that core damage may not be preventable in view of plant conditions. From a case study for an extreme damage condition, it showed that candidate accident management strategies should be evaluated from the viewpoint of effectiveness and feasibility against accident scenarios and extreme damage conditions of the site, especially when employing mobile or portable equipment under BDBEEs within the limited time available to achieve desired goals such as prevention of core damage as well as a reactor vessel failure.

  3. Dynamic thresholds and a summary ROC curve: Assessing prognostic accuracy of longitudinal markers.

    Science.gov (United States)

    Saha-Chaudhuri, P; Heagerty, P J

    2018-04-19

    Cancer patients, chronic kidney disease patients, and subjects infected with HIV are routinely monitored over time using biomarkers that represent key health status indicators. Furthermore, biomarkers are frequently used to guide initiation of new treatments or to inform changes in intervention strategies. Since key medical decisions can be made on the basis of a longitudinal biomarker, it is important to evaluate the potential accuracy associated with longitudinal monitoring. To characterize the overall accuracy of a time-dependent marker, we introduce a summary ROC curve that displays the overall sensitivity associated with a time-dependent threshold that controls time-varying specificity. The proposed statistical methods are similar to concepts considered in disease screening, yet our methods are novel in choosing a potentially time-dependent threshold to define a positive test, and our methods allow time-specific control of the false-positive rate. The proposed summary ROC curve is a natural averaging of time-dependent incident/dynamic ROC curves and therefore provides a single summary of net error rates that can be achieved in the longitudinal setting. Copyright © 2018 John Wiley & Sons, Ltd.

  4. Mobile exhibition in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-04-15

    Since January this year, a mobile atomic energy exhibition has been touring the principal cities of Mexico. In organizing this exhibition, the National Nuclear Energy Commission of Mexico was assisted by the International Atomic Energy Agency which has placed its second mobile radioisotope laboratory at the disposal of the Mexican authorities. In many States of the Republic, the visit of the mobile laboratory has given a powerful impetus to atomic training and research. Universities have made use of the laboratory for the training of young scientists in the basic isotope techniques. As a sequel to the work initiated with its aid, some universities are planning to start regular training courses in this field. The laboratory, which is a gift to the Agency from the United States, has been put to its first assignment in Mexico. It will shortly be sent to Argentina for a period of six months for use in training courses. IAEA's first mobile radioisotope unit, also donated by the United States, has been used for training purposes in Austria, the Federal Republic of Germany, Greece and Yugoslavia, and has now been sent to the Far East

  5. Mobile exhibition in Mexico

    International Nuclear Information System (INIS)

    1960-01-01

    Since January this year, a mobile atomic energy exhibition has been touring the principal cities of Mexico. In organizing this exhibition, the National Nuclear Energy Commission of Mexico was assisted by the International Atomic Energy Agency which has placed its second mobile radioisotope laboratory at the disposal of the Mexican authorities. In many States of the Republic, the visit of the mobile laboratory has given a powerful impetus to atomic training and research. Universities have made use of the laboratory for the training of young scientists in the basic isotope techniques. As a sequel to the work initiated with its aid, some universities are planning to start regular training courses in this field. The laboratory, which is a gift to the Agency from the United States, has been put to its first assignment in Mexico. It will shortly be sent to Argentina for a period of six months for use in training courses. IAEA's first mobile radioisotope unit, also donated by the United States, has been used for training purposes in Austria, the Federal Republic of Germany, Greece and Yugoslavia, and has now been sent to the Far East

  6. Ideal observer estimation and generalized ROC analysis for computer-aided diagnosis

    International Nuclear Information System (INIS)

    Edwards, Darrin C.

    2004-01-01

    The research presented in this dissertation represents an innovative application of computer-aided diagnosis and signal detection theory to the specific task of early detection of breast cancer in the context of screening mammography. A number of automated schemes have been developed in our laboratory to detect masses and clustered microcalcifications in digitized mammograms, on the one hand, and to classify known lesions as malignant or benign, on the other. The development of fully automated classification schemes is difficult, because the output of a detection scheme will contain false-positive detections in addition to detected malignant and benign lesions, resulting in a three-class classification task. Researchers have so far been unable to extend successful tools for analyzing two-class classification tasks, such as receiver operating characteristic (ROC) analysis, to three-class classification tasks. The goals of our research were to use Bayesian artificial neural networks to estimate ideal observer decision variables to both detect and classify clustered microcalcifications and mass lesions in mammograms, and to derive substantial theoretical results indicating potential avenues of approach toward the three-class classification task. Specifically, we have shown that an ideal observer in an N-class classification task achieves an optimal ROC hypersurface, just as the two-class ideal observer achieves an optimal ROC curve; and that an obvious generalization of a well-known two-class performance metric, the area under the ROC curve, is not useful as a performance metric in classification tasks with more than two classes. This work is significant for three reasons. First, it involves the explicit estimation of feature-based (as opposed to image-based) ideal observer decision variables in the tasks of detecting and classifying mammographic lesions. Second, it directly addresses the three-class classification task of distinguishing malignant lesions, benign

  7. Anniversary Exhibition. Nechvolodov.

    Directory of Open Access Journals (Sweden)

    - -

    2006-03-01

    Full Text Available On the 10th of August, 2005 in Tartu (the second biggest educational and cultural city in Estonia Stanislav Nechvolodov's exhibition was opened to show the 5-year cycle of his work, traditional for the author and his admirers. At the opening ceremony Nechvolodov said that the exhibition was the last one and appointed on his 70th anniversary.The architectural and building society in Irkutsk remembers Stanislav Nechvolodov as an architect working on dwelling and civil buildings in 1960-70s. Below are some extracts from the Estonian press.«Postimees» newspaper, December 1993. The interview «Expressionistic naturalist, conservative Nechvolodov» by journalist Eric Linnumyagi. He asks about all the details and describes the troubles experienced by Nechvolodov during the perestroika period in Estonia, for example: the Tartu University refused to install the sculpture of Socrat, the art school refused to engage him as an instructor, the sculpture of Socrat moved to Vrotzlav, Poland, and Nechvolodov moved to Poland to read lectures there.«Tartu» newspaper, November 2000. Mats Oun, artist, says in the article «Nechvolodov: a man of Renaissance»: «Nechvolodov works in Estonia, his works are placed in many local and foreign museums. Regardless some insignificant faults, he deserves a high estimation, and his manysided open exhibition can be an example for other artists. He is a man of Renaissance».

  8. Exploration of analysis methods for diagnostic imaging tests: problems with ROC AUC and confidence scores in CT colonography.

    Science.gov (United States)

    Mallett, Susan; Halligan, Steve; Collins, Gary S; Altman, Doug G

    2014-01-01

    Different methods of evaluating diagnostic performance when comparing diagnostic tests may lead to different results. We compared two such approaches, sensitivity and specificity with area under the Receiver Operating Characteristic Curve (ROC AUC) for the evaluation of CT colonography for the detection of polyps, either with or without computer assisted detection. In a multireader multicase study of 10 readers and 107 cases we compared sensitivity and specificity, using radiological reporting of the presence or absence of polyps, to ROC AUC calculated from confidence scores concerning the presence of polyps. Both methods were assessed against a reference standard. Here we focus on five readers, selected to illustrate issues in design and analysis. We compared diagnostic measures within readers, showing that differences in results are due to statistical methods. Reader performance varied widely depending on whether sensitivity and specificity or ROC AUC was used. There were problems using confidence scores; in assigning scores to all cases; in use of zero scores when no polyps were identified; the bimodal non-normal distribution of scores; fitting ROC curves due to extrapolation beyond the study data; and the undue influence of a few false positive results. Variation due to use of different ROC methods exceeded differences between test results for ROC AUC. The confidence scores recorded in our study violated many assumptions of ROC AUC methods, rendering these methods inappropriate. The problems we identified will apply to other detection studies using confidence scores. We found sensitivity and specificity were a more reliable and clinically appropriate method to compare diagnostic tests.

  9. Geothermal reservoir engineering

    CERN Document Server

    Grant, Malcolm Alister

    2011-01-01

    As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate.  For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference.  This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The bo

  10. ROC-king onwards: intraepithelial lymphocyte counts, distribution & role in coeliac disease mucosal interpretation.

    Science.gov (United States)

    Rostami, Kamran; Marsh, Michael N; Johnson, Matt W; Mohaghegh, Hamid; Heal, Calvin; Holmes, Geoffrey; Ensari, Arzu; Aldulaimi, David; Bancel, Brigitte; Bassotti, Gabrio; Bateman, Adrian; Becheanu, Gabriel; Bozzola, Anna; Carroccio, Antonio; Catassi, Carlo; Ciacci, Carolina; Ciobanu, Alexandra; Danciu, Mihai; Derakhshan, Mohammad H; Elli, Luca; Ferrero, Stefano; Fiorentino, Michelangelo; Fiorino, Marilena; Ganji, Azita; Ghaffarzadehgan, Kamran; Going, James J; Ishaq, Sauid; Mandolesi, Alessandra; Mathews, Sherly; Maxim, Roxana; Mulder, Chris J; Neefjes-Borst, Andra; Robert, Marie; Russo, Ilaria; Rostami-Nejad, Mohammad; Sidoni, Angelo; Sotoudeh, Masoud; Villanacci, Vincenzo; Volta, Umberto; Zali, Mohammad R; Srivastava, Amitabh

    2017-12-01

    Counting intraepithelial lymphocytes (IEL) is central to the histological diagnosis of coeliac disease (CD), but no definitive 'normal' IEL range has ever been published. In this multicentre study, receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off between normal and CD (Marsh III lesion) duodenal mucosa, based on IEL counts on >400 mucosal biopsy specimens. The study was designed at the International Meeting on Digestive Pathology, Bucharest 2015. Investigators from 19 centres, eight countries of three continents, recruited 198 patients with Marsh III histology and 203 controls and used one agreed protocol to count IEL/100 enterocytes in well-oriented duodenal biopsies. Demographic and serological data were also collected. The mean ages of CD and control groups were 45.5 (neonate to 82) and 38.3 (2-88) years. Mean IEL count was 54±18/100 enterocytes in CD and 13±8 in normal controls (p=0.0001). ROC analysis indicated an optimal cut-off point of 25 IEL/100 enterocytes, with 99% sensitivity, 92% specificity and 99.5% area under the curve. Other cut-offs between 20 and 40 IEL were less discriminatory. Additionally, there was a sufficiently high number of biopsies to explore IEL counts across the subclassification of the Marsh III lesion. Our ROC curve analyses demonstrate that for Marsh III lesions, a cut-off of 25 IEL/100 enterocytes optimises discrimination between normal control and CD biopsies. No differences in IEL counts were found between Marsh III a, b and c lesions. There was an indication of a continuously graded dose-response by IEL to environmental (gluten) antigenic influence. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Clinical relevance of the ROC and free-response paradigms for comparing imaging system efficacies

    International Nuclear Information System (INIS)

    Chakraborty, D. P.

    2010-01-01

    Observer performance studies are widely used to assess medical imaging systems. Unlike technical/engineering measurements observer performance include the entire imaging chain and the radiologist. However, the widely used receiver operating characteristic (ROC) method ignores lesion localisation information. The free-response ROC (FROC) method uses the location information to appropriately reward or penalise correct or incorrect localizations, respectively. This paper describes a method for improving the clinical relevance of FROC studies. The method consists of assigning appropriate risk values to the different lesions that may be present on a single image. A high-risk lesion is one that is critical to detect and act upon, and is assigned a higher risk value than a low-risk lesion, one that is relatively innocuous. Instead of simply counting the number of lesions that are detected, as is done in conventional FROC analysis, a risk-weighted count is used. This has the advantage of rewarding detections of high-risk lesions commensurately more than detections of lower risk lesions. Simulations were used to demonstrate that the new method, termed case-based analysis, results in a higher figure of merit for an expert who detects more high-risk lesions than a naive observer who detects more low-risk lesions, even though both detect the same total number of lesions. Conventional free-response analysis is unable to distinguish between the two types of observers. This paper also comments on the issue of clinical relevance of ROC analysis vs. FROC for tasks that involve lesion localisation. (authors)

  12. THE ROLE AND PLACE OF LOGISTIC REGRESSION AND ROC ANALYSIS IN SOLVING MEDICAL DIAGNOSTIC TASK

    Directory of Open Access Journals (Sweden)

    S. G. Grigoryev

    2016-01-01

    Full Text Available Diagnostics, equally with  prevention and  treatment, is a basis of medical science and practice. For its history the medicine  has accumulated a great variety  of diagnostic methods for different diseases and  pathologic conditions. Nevertheless, new  tests,  methods and  tools are being  developed and recommended to application nowadays. Such  indicators as sensitivity and  specificity which  are defined on the basis  of fourfold contingency  tables   construction or  ROC-analysis method with  ROC  – curve  modelling (Receiver operating characteristic are used  as the  methods to estimate the  diagnostic capability. Fourfold  table  is used  with  the purpose to estimate the method which confirms or denies the diagnosis, i.e. a quality indicator. ROC-curve, being a graph, allows making the estimation of model  quality by subdivision of two classes  on the  basis  of identifying the  point  of cutting off a continuous or discrete quantitative attribute.The method of logistic regression technique is introduced as a tool to develop some  mathematical-statistical forecasting model  of probability of the event the researcher is interested in if there are two possible variants of the outcome. The method of ROC-analysis is chosen and described in detail as a tool to estimate the  model  quality. The capabilities of the named methods are demonstrated by a real example of creation  and  efficiency estimation (sensitivity and  specificity of a forecasting model  of probability of complication development in the form of pyodermatitis in children with  atopic dermatitis.

  13. Nagylengyel: an interesting reservoir. [Yugoslovia

    Energy Technology Data Exchange (ETDEWEB)

    Dedinszky, J

    1971-04-01

    The Nagylengyel oil field, discovered in 1951, has oil-producing formations mostly in the Upper-Triassic dolomites, in the Norian-Ractian transition formations, in the Upper-Cretaceous limestones and shales, and in the Miocene. The formation of the reservoir space occurred in many stages. A porous, cavernous fractured reservoir is developed in the Norian principal dolomite. A cavernous fractured reservoir exists in the Cretaceous limestone and in the Cretaceous shale and porous fractured reservoir is developed in the Miocene. The derivation of the model of the reservoir, and the conservative evaluation of the volume of the reservoir made it possible to use secondary recovery.

  14. ROCS: a Reproducibility Index and Confidence Score for Interaction Proteomics Studies

    Directory of Open Access Journals (Sweden)

    Dazard Jean-Eudes

    2012-06-01

    Full Text Available Abstract Background Affinity-Purification Mass-Spectrometry (AP-MS provides a powerful means of identifying protein complexes and interactions. Several important challenges exist in interpreting the results of AP-MS experiments. First, the reproducibility of AP-MS experimental replicates can be low, due both to technical variability and the dynamic nature of protein interactions in the cell. Second, the identification of true protein-protein interactions in AP-MS experiments is subject to inaccuracy due to high false negative and false positive rates. Several experimental approaches can be used to mitigate these drawbacks, including the use of replicated and control experiments and relative quantification to sensitively distinguish true interacting proteins from false ones. Methods To address the issues of reproducibility and accuracy of protein-protein interactions, we introduce a two-step method, called ROCS, which makes use of Indicator Prey Proteins to select reproducible AP-MS experiments, and of Confidence Scores to select specific protein-protein interactions. The Indicator Prey Proteins account for measures of protein identifiability as well as protein reproducibility, effectively allowing removal of outlier experiments that contribute noise and affect downstream inferences. The filtered set of experiments is then used in the Protein-Protein Interaction (PPI scoring step. Prey protein scoring is done by computing a Confidence Score, which accounts for the probability of occurrence of prey proteins in the bait experiments relative to the control experiment, where the significance cutoff parameter is estimated by simultaneously controlling false positives and false negatives against metrics of false discovery rate and biological coherence respectively. In summary, the ROCS method relies on automatic objective criterions for parameter estimation and error-controlled procedures. Results We illustrate the performance of our method by applying

  15. StAR: a simple tool for the statistical comparison of ROC curves

    Directory of Open Access Journals (Sweden)

    Melo Francisco

    2008-06-01

    Full Text Available Abstract Background As in many different areas of science and technology, most important problems in bioinformatics rely on the proper development and assessment of binary classifiers. A generalized assessment of the performance of binary classifiers is typically carried out through the analysis of their receiver operating characteristic (ROC curves. The area under the ROC curve (AUC constitutes a popular indicator of the performance of a binary classifier. However, the assessment of the statistical significance of the difference between any two classifiers based on this measure is not a straightforward task, since not many freely available tools exist. Most existing software is either not free, difficult to use or not easy to automate when a comparative assessment of the performance of many binary classifiers is intended. This constitutes the typical scenario for the optimization of parameters when developing new classifiers and also for their performance validation through the comparison to previous art. Results In this work we describe and release new software to assess the statistical significance of the observed difference between the AUCs of any two classifiers for a common task estimated from paired data or unpaired balanced data. The software is able to perform a pairwise comparison of many classifiers in a single run, without requiring any expert or advanced knowledge to use it. The software relies on a non-parametric test for the difference of the AUCs that accounts for the correlation of the ROC curves. The results are displayed graphically and can be easily customized by the user. A human-readable report is generated and the complete data resulting from the analysis are also available for download, which can be used for further analysis with other software. The software is released as a web server that can be used in any client platform and also as a standalone application for the Linux operating system. Conclusion A new software for

  16. A Primer on Receiver Operating Characteristic Analysis and Diagnostic Efficiency Statistics for Pediatric Psychology: We Are Ready to ROC

    Science.gov (United States)

    2014-01-01

    Objective To offer a practical demonstration of receiver operating characteristic (ROC) analyses, diagnostic efficiency statistics, and their application to clinical decision making using a popular parent checklist to assess for potential mood disorder. Method Secondary analyses of data from 589 families seeking outpatient mental health services, completing the Child Behavior Checklist and semi-structured diagnostic interviews. Results Internalizing Problems raw scores discriminated mood disorders significantly better than did age- and gender-normed T scores, or an Affective Problems score. Internalizing scores 30 had a diagnostic likelihood ratio of 7.4. Conclusions This study illustrates a series of steps in defining a clinical problem, operationalizing it, selecting a valid study design, and using ROC analyses to generate statistics that support clinical decisions. The ROC framework offers important advantages for clinical interpretation. Appendices include sample scripts using SPSS and R to check assumptions and conduct ROC analyses. PMID:23965298

  17. Verification of a model for the detection of intrauterine growth restriction (IUGR) by receiver operating characteristics (ROC)

    Science.gov (United States)

    Liu, Pengbo; Mongelli, Max; Mondry, Adrian

    2004-07-01

    The purpose of this study is to verify by Receiver Operating Characteristics (ROC) a mathematical model supporting the hypothesis that IUGR can be diagnosed by estimating growth velocity. The ROC compare computerized simulation results with clinical data from 325 pregnant British women. Each patient had 6 consecutive ultrasound examinations for fetal abdominal circumference (fac). Customized and un-customized fetal weights were calculated according to Hadlock"s formula. IUGR was diagnosed by the clinical standard, i.e. estimated weight below the tenth percentile. Growth velocity was estimated by calculating the changes of fac (Dzfac/dt) at various time intervals from 3 to 10 weeks. Finally, ROC was used to compare the methods. At 3~4 weeks scan interval, the area under the ROC curve is 0.68 for customized data and 0.66 for the uncustomized data with 95% confidence interval. Comparison between simulation data and real pregnancies verified that the model is clinically acceptable.

  18. Parallel reservoir simulator computations

    International Nuclear Information System (INIS)

    Hemanth-Kumar, K.; Young, L.C.

    1995-01-01

    The adaptation of a reservoir simulator for parallel computations is described. The simulator was originally designed for vector processors. It performs approximately 99% of its calculations in vector/parallel mode and relative to scalar calculations it achieves speedups of 65 and 81 for black oil and EOS simulations, respectively on the CRAY C-90

  19. unconventional natural gas reservoirs

    International Nuclear Information System (INIS)

    Correa G, Tomas F; Osorio, Nelson; Restrepo R, Dora P

    2009-01-01

    This work is an exploration about different unconventional gas reservoirs worldwide: coal bed methane, tight gas, shale gas and gas hydrate? describing aspects such as definition, reserves, production methods, environmental issues and economics. The overview also mentioned preliminary studies about these sources in Colombia.

  20. Smart waterflooding in carbonate reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Zahid, A.

    2012-02-15

    are carried out in order to understand mechanisms of the crude oil viscosity reduction and emulsion formation. We observed that a heavy oil (that with a large fraction of heavy components) exhibited viscosity reduction in contact with brine, while a light crude oil exhibited emulsion formation. Most of reported high salinity waterflooding studies were carried out with outcrop chalk core plugs, and by performing spontaneous imbibition rather than forced flooding. The objective of the third step of this project was to investigate the potential of high salinity waterflooding process by carrying out experiments with reservoir chalk samples. We carried out waterflooding instead of spontaneous imbibition using core plugs with and without aging. The total oil recovery, recovery rate and interaction mechanisms of ions with rock were studied for different injected fluids under different temperatures and wettability conditions. Experimental results demonstrate that the oil recovery mechanism under high salinity seawater flooding at high temperatures is different for the different chalk rocks (outcrop and reservoir), although they have similar surface area and reactivity of the potential determining ions. In the last decade, laboratory waterflooding experiments and field tests have proven increase in oil recovery from sandstone reservoirs by injecting brine of low salinity. However, this effect has not been thoroughly investigated for carbonates. At the final stage of this project, we have experimentally investigated the oil recovery potential of low salinity water flooding in the carbonate rocks. We used both reservoir carbonate and outcrop chalk core plugs. The flooding experiments were carried out initially with the seawater. Afterwards the contribution to oil recovery was evaluated by sequential injection of various diluted versions of the seawater. The significance of this work may be summarized in five main findings: 1) Injection of sulfate rich brine may lead to

  1. MODELING URBAN DYNAMICS USING RANDOM FOREST: IMPLEMENTING ROC AND TOC FOR MODEL EVALUATION

    Directory of Open Access Journals (Sweden)

    M. Ahmadlou

    2016-06-01

    Full Text Available The importance of spatial accuracy of land use/cover change maps necessitates the use of high performance models. To reach this goal, calibrating machine learning (ML approaches to model land use/cover conversions have received increasing interest among the scholars. This originates from the strength of these techniques as they powerfully account for the complex relationships underlying urban dynamics. Compared to other ML techniques, random forest has rarely been used for modeling urban growth. This paper, drawing on information from the multi-temporal Landsat satellite images of 1985, 2000 and 2015, calibrates a random forest regression (RFR model to quantify the variable importance and simulation of urban change spatial patterns. The results and performance of RFR model were evaluated using two complementary tools, relative operating characteristics (ROC and total operating characteristics (TOC, by overlaying the map of observed change and the modeled suitability map for land use change (error map. The suitability map produced by RFR model showed 82.48% area under curve for the ROC model which indicates a very good performance and highlights its appropriateness for simulating urban growth.

  2. Measuring diagnostic and predictive accuracy in disease management: an introduction to receiver operating characteristic (ROC) analysis.

    Science.gov (United States)

    Linden, Ariel

    2006-04-01

    Diagnostic or predictive accuracy concerns are common in all phases of a disease management (DM) programme, and ultimately play an influential role in the assessment of programme effectiveness. Areas, such as the identification of diseased patients, predictive modelling of future health status and costs and risk stratification, are just a few of the domains in which assessment of accuracy is beneficial, if not critical. The most commonly used analytical model for this purpose is the standard 2 x 2 table method in which sensitivity and specificity are calculated. However, there are several limitations to this approach, including the reliance on a single defined criterion or cut-off for determining a true-positive result, use of non-standardized measurement instruments and sensitivity to outcome prevalence. This paper introduces the receiver operator characteristic (ROC) analysis as a more appropriate and useful technique for assessing diagnostic and predictive accuracy in DM. Its advantages include; testing accuracy across the entire range of scores and thereby not requiring a predetermined cut-off point, easily examined visual and statistical comparisons across tests or scores, and independence from outcome prevalence. Therefore the implementation of ROC as an evaluation tool should be strongly considered in the various phases of a DM programme.

  3. Diagnostic tests’ decision-making rules based upon analysis of ROC-curves

    Directory of Open Access Journals (Sweden)

    Л. В. Батюк

    2015-10-01

    Full Text Available In this paper we propose the model which substantiates diagnostics decision making based on the analysis of Receiver Operating Characteristic curves (ROC-curves and predicts optimal values of diagnostic indicators of biomedical information. To assess the quality of the test result prediction the standard criteria of the sensitivity and specificity of the model were used. Values of these criteria were calculated for the cases when the sensitivity of the test was greater than specificity by several times, when the number of correct diagnoses was maximal, when the sensitivity of the test was equal to its specificity and the sensitivity of the test was several times greater than the specificity of the test. To assess the significance of the factor characteristics and to compare the prognostic characteristics of models we used mathematical modeling and plotting the ROC-curves. The optimal value of the diagnostic indicator was found to be achieved when the sensitivity of the test is equal to its specificity. The model was adapted to solve the case when the sensitivity of the test is greater than specificity of the test.

  4. Receiver Operating Characteristic (ROC to Determine Cut-Off Points of Biomarkers in Lung Cancer Patients

    Directory of Open Access Journals (Sweden)

    Heidi L. Weiss

    2004-01-01

    Full Text Available The role of biomarkers in disease prognosis continues to be an important investigation in many cancer studies. In order for these biomarkers to have practical application in clinical decision making regarding patient treatment and follow-up, it is common to dichotomize patients into those with low vs. high expression levels. In this study, receiver operating characteristic (ROC curves, area under the curve (AUC of the ROC, sensitivity, specificity, as well as likelihood ratios were calculated to determine levels of growth factor biomarkers that best differentiate lung cancer cases versus control subjects. Selected cut-off points for p185erbB-2 and EGFR membrane appear to have good discriminating power to differentiate control tissues versus uninvolved tissues from patients with lung cancer (AUC = 89% and 90%, respectively; while AUC increased to at least 90% for selected cut-off points for p185erbB-2 membrane, EGFR membrane, and FASE when comparing between control versus carcinoma tissues from lung cancer cases. Using data from control subjects compared to patients with lung cancer, we presented a simple and intuitive approach to determine dichotomized levels of biomarkers and validated the value of these biomarkers as surrogate endpoints for cancer outcome.

  5. APPLICATION OF INTEGRATED RESERVOIR MANAGEMENT AND RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jack Bergeron; Tom Blasingame; Louis Doublet; Mohan Kelkar; George Freeman; Jeff Callard; David Moore; David Davies; Richard Vessell; Brian Pregger; Bill Dixon; Bryce Bezant

    2000-03-01

    Reservoir performance and characterization are vital parameters during the development phase of a project. Infill drilling of wells on a uniform spacing, without regard to characterization does not optimize development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, especially carbonate reservoirs. These reservoirs are typically characterized by: (1) large, discontinuous pay intervals; (2) vertical and lateral changes in reservoir properties; (3) low reservoir energy; (4) high residual oil saturation; and (5) low recovery efficiency. The operational problems they encounter in these types of reservoirs include: (1) poor or inadequate completions and stimulations; (2) early water breakthrough; (3) poor reservoir sweep efficiency in contacting oil throughout the reservoir as well as in the nearby well regions; (4) channeling of injected fluids due to preferential fracturing caused by excessive injection rates; and (5) limited data availability and poor data quality. Infill drilling operations only need target areas of the reservoir which will be economically successful. If the most productive areas of a reservoir can be accurately identified by combining the results of geological, petrophysical, reservoir performance, and pressure transient analyses, then this ''integrated'' approach can be used to optimize reservoir performance during secondary and tertiary recovery operations without resorting to ''blanket'' infill drilling methods. New and emerging technologies such as geostatistical modeling, rock typing, and rigorous decline type curve analysis can be used to quantify reservoir quality and the degree of interwell communication. These results can then be used to develop a 3-D simulation model for prediction of infill locations. The application of reservoir surveillance techniques to identify additional reservoir ''pay'' zones

  6. Static reservoir modeling of the Bahariya reservoirs for the oilfields development in South Umbarka area, Western Desert, Egypt

    Science.gov (United States)

    Abdel-Fattah, Mohamed I.; Metwalli, Farouk I.; Mesilhi, El Sayed I.

    2018-02-01

    3D static reservoir modeling of the Bahariya reservoirs using seismic and wells data can be a relevant part of an overall strategy for the oilfields development in South Umbarka area (Western Desert, Egypt). The seismic data is used to build the 3D grid, including fault sticks for the fault modeling, and horizon interpretations and surfaces for horizon modeling. The 3D grid is the digital representation of the structural geology of Bahariya Formation. When we got a reasonably accurate representation, we fill the 3D grid with facies and petrophysical properties to simulate it, to gain a more precise understanding of the reservoir properties behavior. Sequential Indicator Simulation (SIS) and Sequential Gaussian Simulation (SGS) techniques are the stochastic algorithms used to spatially distribute discrete reservoir properties (facies) and continuous reservoir properties (shale volume, porosity, and water saturation) respectively within the created 3D grid throughout property modeling. The structural model of Bahariya Formation exhibits the trapping mechanism which is a fault assisted anticlinal closure trending NW-SE. This major fault breaks the reservoirs into two major fault blocks (North Block and South Block). Petrophysical models classified Lower Bahariya reservoir as a moderate to good reservoir rather than Upper Bahariya reservoir in terms of facies, with good porosity and permeability, low water saturation, and moderate net to gross. The Original Oil In Place (OOIP) values of modeled Bahariya reservoirs show hydrocarbon accumulation in economic quantity, considering the high structural dips at the central part of South Umbarka area. The powerful of 3D static modeling technique has provided a considerable insight into the future prediction of Bahariya reservoirs performance and production behavior.

  7. Correlation of free-response and receiver-operating-characteristic area-under-the-curve estimates: Results from independently conducted FROC/ROC studies in mammography

    International Nuclear Information System (INIS)

    Zanca, Federica; Hillis, Stephen L.; Claus, Filip; Van Ongeval, Chantal; Celis, Valerie; Provoost, Veerle; Yoon, Hong-Jun; Bosmans, Hilde

    2012-01-01

    Purpose: From independently conducted free-response receiver operating characteristic (FROC) and receiver operating characteristic (ROC) experiments, to study fixed-reader associations between three estimators: the area under the alternative FROC (AFROC) curve computed from FROC data, the area under the ROC curve computed from FROC highest rating data, and the area under the ROC curve computed from confidence-of-disease ratings. Methods: Two hundred mammograms, 100 of which were abnormal, were processed by two image-processing algorithms and interpreted by four radiologists under the FROC paradigm. From the FROC data, inferred-ROC data were derived, using the highest rating assumption. Eighteen months afterwards, the images were interpreted by the same radiologists under the conventional ROC paradigm; conventional-ROC data (in contrast to inferred-ROC data) were obtained. FROC and ROC (inferred, conventional) data were analyzed using the nonparametric area-under-the-curve (AUC), (AFROC and ROC curve, respectively). Pearson correlation was used to quantify the degree of association between the modality-specific AUC indices and standard errors were computed using the bootstrap-after-bootstrap method. The magnitude of the correlations was assessed by comparison with computed Obuchowski-Rockette fixed reader correlations. Results: Average Pearson correlations (with 95% confidence intervals in square brackets) were: Corr(FROC, inferred ROC) = 0.76[0.64, 0.84] > Corr(inferred ROC, conventional ROC) = 0.40[0.18, 0.58] > Corr (FROC, conventional ROC) = 0.32[0.16, 0.46]. Conclusions: Correlation between FROC and inferred-ROC data AUC estimates was high. Correlation between inferred- and conventional-ROC AUC was similar to the correlation between two modalities for a single reader using one estimation method, suggesting that the highest rating assumption might be questionable.

  8. An Effective Reservoir Parameter for Seismic Characterization of Organic Shale Reservoir

    Science.gov (United States)

    Zhao, Luanxiao; Qin, Xuan; Zhang, Jinqiang; Liu, Xiwu; Han, De-hua; Geng, Jianhua; Xiong, Yineng

    2017-12-01

    Sweet spots identification for unconventional shale reservoirs involves detection of organic-rich zones with abundant porosity. However, commonly used elastic attributes, such as P- and S-impedances, often show poor correlations with porosity and organic matter content separately and thus make the seismic characterization of sweet spots challenging. Based on an extensive analysis of worldwide laboratory database of core measurements, we find that P- and S-impedances exhibit much improved linear correlations with the sum of volume fraction of organic matter and porosity than the single parameter of organic matter volume fraction or porosity. Importantly, from the geological perspective, porosity in conjunction with organic matter content is also directly indicative of the total hydrocarbon content of shale resources plays. Consequently, we propose an effective reservoir parameter (ERP), the sum of volume fraction of organic matter and porosity, to bridge the gap between hydrocarbon accumulation and seismic measurements in organic shale reservoirs. ERP acts as the first-order factor in controlling the elastic properties as well as characterizing the hydrocarbon storage capacity of organic shale reservoirs. We also use rock physics modeling to demonstrate why there exists an improved linear correlation between elastic impedances and ERP. A case study in a shale gas reservoir illustrates that seismic-derived ERP can be effectively used to characterize the total gas content in place, which is also confirmed by the production well.

  9. Chalk as a reservoir

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    , and the best reservoir properties are typically found in mudstone intervals. Chalk mudstones vary a lot though. The best mudstones are purely calcitic, well sorted and may have been redeposited by traction currents. Other mudstones are rich in very fine grained silica, which takes up pore space and thus...... basin, so stylolite formation in the chalk is controlled by effective burial stress. The stylolites are zones of calcite dissolution and probably are the source of calcite for porefilling cementation which is typical in water zone chalk and also affect the reservoirs to different extent. The relatively...... have hardly any stylolites and can have porosity above 40% or even 50% and thus also have relatively high permeability. Such intervals have the problem though, that increasing effective stress caused by hydrocarbon production results in mechanical compaction and overall subsidence. Most other chalk...

  10. Work reservoirs in thermodynamics

    International Nuclear Information System (INIS)

    Anacleto, Joaquim

    2010-01-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  11. Work reservoirs in thermodynamics

    Science.gov (United States)

    Anacleto, Joaquim

    2010-05-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  12. Observer performance in detecting multiple radiographic signals: prediction and analysis using a generalized ROC approach

    International Nuclear Information System (INIS)

    Metz, C.E.; Starr, S.J.; Lusted, L.B.

    1975-01-01

    The theories of decision processes and signal detection provide a framework for the evaluation of observer performance. Some radiologic procedures involve a search for multiple similar lesions, as in gallstone or pneumoconiosis examinations. A model is presented which attempts to predict, from the conventional receiver operating characteristic (ROC) curve describing the detectability of a single visual signal in a radiograph, observer performance in an experiment requiring detection of more than one such signal. An experiment is described which tests the validity of this model for the case of detecting the presence of zero, one, or two low-contrast radiographic images of a two-mm.-diameter lucite bead embedded in radiographic mottle. Results from six observers, including three radiologists, confirm the validity of the model and suggest that human observer performance for relatively complex detection tasks can be predicted from the results of simpler experiments

  13. Advantageous Reservoir Characterization Technology in Extra Low Permeability Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Yutian Luo

    2017-01-01

    Full Text Available This paper took extra low permeability reservoirs in Dagang Liujianfang Oilfield as an example and analyzed different types of microscopic pore structures by SEM, casting thin sections fluorescence microscope, and so on. With adoption of rate-controlled mercury penetration, NMR, and some other advanced techniques, based on evaluation parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and clay content, the classification and assessment method of extra low permeability reservoirs was improved and the parameter boundaries of the advantageous reservoirs were established. The physical properties of reservoirs with different depth are different. Clay mineral variation range is 7.0%, and throat radius variation range is 1.81 μm, and start pressure gradient range is 0.23 MPa/m, and movable fluid percentage change range is 17.4%. The class IV reservoirs account for 9.56%, class II reservoirs account for 12.16%, and class III reservoirs account for 78.29%. According to the comparison of different development methods, class II reservoir is most suitable for waterflooding development, and class IV reservoir is most suitable for gas injection development. Taking into account the gas injection in the upper section of the reservoir, the next section of water injection development will achieve the best results.

  14. Diagnostic accuracy of atypical p-ANCA in autoimmune hepatitis using ROC- and multivariate regression analysis.

    Science.gov (United States)

    Terjung, B; Bogsch, F; Klein, R; Söhne, J; Reichel, C; Wasmuth, J-C; Beuers, U; Sauerbruch, T; Spengler, U

    2004-09-29

    Antineutrophil cytoplasmic antibodies (atypical p-ANCA) are detected at high prevalence in sera from patients with autoimmune hepatitis (AIH), but their diagnostic relevance for AIH has not been systematically evaluated so far. Here, we studied sera from 357 patients with autoimmune (autoimmune hepatitis n=175, primary sclerosing cholangitis (PSC) n=35, primary biliary cirrhosis n=45), non-autoimmune chronic liver disease (alcoholic liver cirrhosis n=62; chronic hepatitis C virus infection (HCV) n=21) or healthy controls (n=19) for the presence of various non-organ specific autoantibodies. Atypical p-ANCA, antinuclear antibodies (ANA), antibodies against smooth muscles (SMA), antibodies against liver/kidney microsomes (anti-Lkm1) and antimitochondrial antibodies (AMA) were detected by indirect immunofluorescence microscopy, antibodies against the M2 antigen (anti-M2), antibodies against soluble liver antigen (anti-SLA/LP) and anti-Lkm1 by using enzyme linked immunosorbent assays. To define the diagnostic precision of the autoantibodies, results of autoantibody testing were analyzed by receiver operating characteristics (ROC) and forward conditional logistic regression analysis. Atypical p-ANCA were detected at high prevalence in sera from patients with AIH (81%) and PSC (94%). ROC- and logistic regression analysis revealed atypical p-ANCA and SMA, but not ANA as significant diagnostic seromarkers for AIH (atypical p-ANCA: AUC 0.754+/-0.026, odds ratio [OR] 3.4; SMA: 0.652+/-0.028, OR 4.1). Atypical p-ANCA also emerged as the only diagnostically relevant seromarker for PSC (AUC 0.690+/-0.04, OR 3.4). None of the tested antibodies yielded a significant diagnostic accuracy for patients with alcoholic liver cirrhosis, HCV or healthy controls. Atypical p-ANCA along with SMA represent a seromarker with high diagnostic accuracy for AIH and should be explicitly considered in a revised version of the diagnostic score for AIH.

  15. Optimizing area under the ROC curve using semi-supervised learning.

    Science.gov (United States)

    Wang, Shijun; Li, Diana; Petrick, Nicholas; Sahiner, Berkman; Linguraru, Marius George; Summers, Ronald M

    2015-01-01

    Receiver operating characteristic (ROC) analysis is a standard methodology to evaluate the performance of a binary classification system. The area under the ROC curve (AUC) is a performance metric that summarizes how well a classifier separates two classes. Traditional AUC optimization techniques are supervised learning methods that utilize only labeled data (i.e., the true class is known for all data) to train the classifiers. In this work, inspired by semi-supervised and transductive learning, we propose two new AUC optimization algorithms hereby referred to as semi-supervised learning receiver operating characteristic (SSLROC) algorithms, which utilize unlabeled test samples in classifier training to maximize AUC. Unlabeled samples are incorporated into the AUC optimization process, and their ranking relationships to labeled positive and negative training samples are considered as optimization constraints. The introduced test samples will cause the learned decision boundary in a multidimensional feature space to adapt not only to the distribution of labeled training data, but also to the distribution of unlabeled test data. We formulate the semi-supervised AUC optimization problem as a semi-definite programming problem based on the margin maximization theory. The proposed methods SSLROC1 (1-norm) and SSLROC2 (2-norm) were evaluated using 34 (determined by power analysis) randomly selected datasets from the University of California, Irvine machine learning repository. Wilcoxon signed rank tests showed that the proposed methods achieved significant improvement compared with state-of-the-art methods. The proposed methods were also applied to a CT colonography dataset for colonic polyp classification and showed promising results.

  16. Exhibition

    CERN Multimedia

    Staff Association

    2014-01-01

    Energie sombre, matière noire J.-J. Dalmais - J. Maréchal Du 11 au 27 novembre 2014, CERN Meyrin, Bâtiment principal A l’image des particules atomiques qui ont tissé des liens pour créer la matière, deux artistes haut bugistes croisent leurs regards et conjuguent leurs expressions singulières pour faire naître une vision commune de l’univers, produit des forces primordiales. Les sculptures de Jean-Jacques Dalmais et les peintures de Jacki Maréchal se rencontrent pour la première fois et se racontent par un enrichissement mutuel la belle histoire de la Vie. Dialogue magique des œuvres en mouvement qui questionnent en écho l’énergie sombre et la matière noire. Cette harmonieuse confluence de jeux de miroir et de résonnance illumine de poésie et de sobriété l’espace expos&...

  17. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Gaïa Manuella Cany Du 10 au 28 avril 2017 CERN Meyrin, Bâtiment principal Oiseau - Manuella Cany. Tableaux abstraits inspirés de vues satellites ou photos prises du ciel. Certains sont à la frontière du figuratif alors que d'autres permettent de laisser libre cours à son imagination. Aux détails infinis, ces tableaux sont faits pour être vus de loin et de près grâce à une attention toute particulière apportée aux effets de matières et aux couleurs le long de volutes tantôt nuancées tantôt contrastées.   Pour plus d’informations : staff.association@cern.ch | Tél: 022 766 37 38

  18. Exhibition

    CERN Document Server

    Staff Association

    2018-01-01

    En dehors des frontières Maxence Piquet Du 2 au 11 mai 2018 | CERN Meyrin, Bâtiment principal Exposition de peinture d'un artiste autodidacte Maxence Piquet (signature artiste M-P), avec différentes techniques (acrylique, huile, fusain, collage...) et sur différents supports. Un art souvent brut et parfois provoquant, avec des touches expressionnistes et cubistes principale origine de son art. Des œuvres souvent vivent et colorées... Cette exposition est la première en dehors d ses frontières Lorraine et a pour but de faire voyager son art au regard du plus grand nombre . Pour plus d’informations et demandes d’accès : staff.association@cern.ch | Tél: 022 766 37 38

  19. Exhibition

    CERN Multimedia

    Staff Association

    2016-01-01

    The Elementary Particles of Painting Alfonso Fratteggiani Bianchi and Ermanno Imbergamo From September 26 to October 7, 2016 CERN Meyrin, Main Building With intentions similar to those of CERN physicists, the artist Alfonso Fratteggiani Bianchi investigates the color pigment, studying its interaction with light and with the support on which it is deposited. He creates monochrome paintings by spreading the color pigment in the pure state on stones, without using glue or any other type of adhesive. With intentions similar to artists, the physicist Ermanno Imbergamo investigates the use of luminescent wavelength shifters, materials commonly used in Particle Physics, for art. He creates other monochrome artworks, which disclose further aspects of interaction among light, color pigments and support. For more information: staff.association@cern.ch | Tel: 022 767 28 19

  20. Exhibition

    CERN Multimedia

    Staff Association

    2016-01-01

    COLORATION Sandra Duchêne From September 5 to 16, 2016 CERN Meyrin, Main Building La recherche de l’Universel. Après tout ! C’est de l’Amour ! What else to say ? …La couleur, l’ENERGIE de la vie…

  1. Exhibition

    CERN Multimedia

    Staff Association

    2014-01-01

      Parallels vision Astronomical subjects which evoke extrasensory kinetic visions Alberto Di Fabio From 8 to 10 October, CERN Meyrin, Main Building In the framework of Italy@cern, the Staff Association presents Alberto Di Fabio. Di Fabio’s work is inspired by the fundamental laws of the physical world, as well as organic elements and their interrelation. His paintings and works on paper merge the worlds of art and science, depicting natural forms and biological structures in vivid colour and imaginative detail. For all additional information: staff.association@cern.ch | Tel: 022 767 28 19

  2. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Le Point Isabelle Gailland Du 20 février au 3 mars 2017 CERN Meyrin, Bâtiment principal La Diagonale - Isabelle Gailland. Au départ, un toujours même point minuscule posé au centre de ce que la toile est un espace. Une réplique d'autres points, condensés, alignés, isolés, disséminés construiront dans leur extension, la ligne. Ces lignes, croisées, courbées, déviées, prolongées, seront la structure contenant et séparant la matière des couleurs. La rotation de chaque toile en cours d'exécution va offrir un accès illimité à la non-forme et à la forme. Le point final sera l'ouverture sur différents points de vue de ce que le point et la ligne sont devenus une représentation pour l'œil et l'im...

  3. Exhibition

    CERN Multimedia

    Staff Association

    2018-01-01

    La danse mécanique Daria Grigoryeva Du 22 mai au 1er juin 2018 | CERN Meyrin, Bâtiment principal La danse mécanique est une métaphore large. La mécanique établit les règles et les limites, les frontières dans lesquelles la vie et la créativité peuvent se développer. La musique est « mathématique », une poupée mécanique se tourne toujours dans la même direction, selon les règles prescrites par la nature les fleurs fleurissent au printemps. Même s'ils ne le voulaient pas. La participation à la "danse mécanique" est prédéterminée et inévitable. Il ne reste plus qu'à comprendre comment le faire "magnifiquement". En tout, il y a une signification cachée et un...

  4. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Still Life Jérémy Bajulaz Du 25 septembre au 6 octobre 2017 CERN Meyrin, Main Building (Aubergine - Jérémy Bajulaz) Né en 1991 en Haute-Savoie, France. Diplômé de l'Ecole Emile Cohl à Lyon, Jérémy Bajulaz intègre en 2014 le programme d'artiste en résidence au Centre Genevois de Gravure Contemporaine. C'est là que son travail prendra corps, autour de la lumière et de ses vibrations aux travers de sujets comme le portrait et la nature morte, dans le souci de l'observation; le regard prenant une place importante dans le processus créatif. Lauréat 2017 du VII Premio AAAC, son travail a été présenté dans de nombreuses expositions collectives, en 2015 au Bâtiment d’Art Contemporain de Genève, en 2016 au 89e Salon de Lyon et du ...

  5. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Œuvres recentes Fabienne Wyler Du 6 au 17 février 2017 CERN Meyrin, Bâtiment principal L'escalier du diable B - aquarelle, encre de Chine XLV - Fabienne Wyler. En relation avec certains procédés d’écriture contemporaine (par ex. Webern ou certaines musiques conçues par ordinateur), les compositions picturales de Fabienne Wyler s’élaborent à partir de « modules » (groupes de quadrangles) qu’elle reproduit en leur faisant subir toutes sortes de transformations et de déplacements : étirements, renversements, rotations, effet miroir, transpositions, déphasages, superpositions, etc., et ceci à toutes les échelles. Au fil des œuvres sont apparues des séries intitulées, Bifurcations, Intermittences, Attracteurs étranges, Polyrythmies. Ces titres ont un lien &e...

  6. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Les vibrantes Patrick Robbe-Grillet Du 30 octobre au 10 novembre 2017 CERN Meyrin, Main Building Patrick Robbe-Grillet - Feux d'artifices Qui est Patrick Robbe-Grillet ? Artiste Franco-Suisse, né en 1968 à Genève. En recherche du sentiment de paix, autodidacte, après un séjour en Chine en 2000, puis au Japon en 2002, suivi d’un long questionnement, il trouve sa voie dans la peinture, élément libérateur de sa créativité et expression de sa sensibilité à fleur de peau. « La Chine m’a enseigné les courbes, les nuances. Le Japon, la ligne droite, la rigueur. » Vous avez su rendre visible l'invisible ! - commentaire de Monsieur Fawaz Gruosi Pour plus d’informations et demandes d’accès : staff.association@cern.ch | Tél : 022 766 37 38

  7. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    La couleur des jours oriSio Du 2 au 12 mai 2017 CERN Meyrin, Bâtiment principal oriSio - Motus Suite à un fort intérêt pour la Chine et une curiosité pour un médium très ancien, la laque ! Je réinterprète cet art à travers un style abstrait. Je présente ici des laques sur aluminium, travaillés au plasma et ensuite colorés à l’aide de pigments pour l’essentiel. Mes œuvres je les veux brutes, déchirées, évanescentes, gondolées, voire trouées mais avec une belle approche de profondeur de la couleur.   Pour plus d’informations : staff.association@cern.ch | Tél: 022 766 37 38

  8. Exhibition

    CERN Multimedia

    Staff Association

    2011-01-01

    Jan Hladky, physicien de l'Institut de Physique de l'Académie des Sciences de la République tchèque, et membre de la collaboration Alice, expose ses œuvres au Bâtiment principal du 20 avril au 6 mai. Son exposition est dédiée aux victimes du séisme de Sendai. Des copies de ses œuvres seront mises en vente et les sommes récoltées seront versées au profit des victimes.

  9. Exhibition

    CERN Multimedia

    Staff Association

    2016-01-01

    La mosaïque ou quand détruire permet de construire Lauren Decamps Du 28 novembre au 9 décembre 2016 CERN Meyrin, Bâtiment principal Paysage d'Amsterdam - Lauren Decamps On ne doit jamais rien détruire qu'on ne soit sûr de pouvoir remplacer aussi avantageusement " écrivait Plutarque dans ses Œuvres morales du 1er siècle après JC. L'artiste mosaïste Lauren Decamps adhère à cette idée et tente à sa manière de donner une nouvelle vie à ses matériaux en les taillant puis les réassemblant, créant ainsi des œuvres abstraites et figuratives.

  10. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Firmament des toiles Joëlle Lalagüe Du 6 au 16 juin 2017 CERN Meyrin, Bâtiment principal Phylaë Voyage - Joëlle Lalagüe. Each picture is an invitation for a cosmic trip. This is a whispering of soul, which comes from origins. A symphony of the world, some notes of love, a harmony for us to fly to infinity. Pour plus d’informations et demandes d'accès : staff.association@cern.ch | Tél: 022 766 37 38

  11. Exhibition

    CERN Multimedia

    Staff Association

    2018-01-01

    Univers Du 9 au 20 avril 2018 | CERN Meyrin, Bâtiment principal Stéphanie Cousin Obsédée par les rêves, les mondes surréalistes et insolites, je m’empare de formes provenant des mes propres travaux photographiques ou d’images que je modifie et mixe. Je fais évoluer mes univers oniriques de femmes-animaux ainsi que mes espaces et natures imaginaires. Avec ma démarche artistique, je cherche à mettre en images nos rêves et nos cauchemars, l’irréel et le surréel, le mystique et les affres de notre inconscient. Je cherche à représenter tout ce qui sommeille au plus profond de nous-même à l’aide de symboles, parfois en utilisant des images de cultures ancestrales. Photographie-collage, je cherche à ajouter quelques notes à la définition de la photographie du 21iè...

  12. Exhibition

    CERN Multimedia

    Staff Association

    2017-01-01

    Harmonie Nathalie Lenoir Du 4 au 15 septembre 2017 CERN Meyrin, Bâtiment principal Peindre est un langage. Le tracé du pinceau sur le lin en est l'expression. A qui appartient un tableau en définitive ? A celui qui l'a peint ? A celui qui le regarde ? A celui qui l'emporte ? La peinture est une émotion partagée... Laissez-vous projeter de l'autre côté de la toile, prenez un moment pour rêver, en harmonie avec les éléments, parce-que la peinture parle à votre âme… Pour plus d’informations et demandes d’accès : staff.association@cern.ch | Tél : 022 766 37 38

  13. Exhibition

    CERN Multimedia

    Staff Association

    2018-01-01

    Cosmos KOLI Du 15 au 26 janvier 2018 CERN Meyrin, Main Building (Nébuleuse d'Orion- KOLI) KOLI, Artiste confirmé, diplômé de l’Académie de Beaux Arts de Tirana, depuis 26 ans en Suisse, où il a participé à maintes expositions collectives et organisé 10 expositions privées avec  beaucoup de succès, s’exprime actuellement dans un bonheur de couleur et de matières qui côtoient des hautes sphères… le cosmos ! Gagnant d’un premier prix lors d’une exposition collective organisée par le consulat Italien, il s’est installé au bord du lac dans le canton de Vaud où il vit depuis maintenant déjà 13 ans. www.kolicreation.com Pour plus d’informations et demandes d’accès : staff.association@cern.ch | T&eacut...

  14. Overspill avalanching in a dense reservoir network

    Science.gov (United States)

    Mamede, George L.; Araújo, Nuno A. M.; Schneider, Christian M.; de Araújo, José Carlos; Herrmann, Hans J.

    2012-01-01

    Sustainability of communities, agriculture, and industry is strongly dependent on an effective storage and supply of water resources. In some regions the economic growth has led to a level of water demand that can only be accomplished through efficient reservoir networks. Such infrastructures are not always planned at larger scale but rather made by farmers according to their local needs of irrigation during droughts. Based on extensive data from the upper Jaguaribe basin, one of the world’s largest system of reservoirs, located in the Brazilian semiarid northeast, we reveal that surprisingly it self-organizes into a scale-free network exhibiting also a power-law in the distribution of the lakes and avalanches of discharges. With a new self-organized-criticality-type model we manage to explain the novel critical exponents. Implementing a flow model we are able to reproduce the measured overspill evolution providing a tool for catastrophe mitigation and future planning. PMID:22529343

  15. Exhibition at the AAA library

    DEFF Research Database (Denmark)

    2013-01-01

    Sonnesgade 11 The exhibition at the AAA library presents selected work produced by students prior to the exhibition of installations in project and praxis constructing an archive at Sonnesgade 11. The exhibition at Sonnesgade 11 was the culmination of collaboration with SLETH architects and studio...

  16. Electrokinetic Flow in Microchannels with Finite Reservoir Size Effects

    International Nuclear Information System (INIS)

    Yan, D; Yang, C; Nguyen, N-T; Huang, X

    2006-01-01

    In electrokinetically-driven microfluidic applications, reservoirs are indispensable and have finite sizes. During operation processes, as the liquid level difference in reservoirs keeps changing as time elapses, the flow characteristics in a microchannel exhibit a combination of the electroosmotic flow and the time-dependent induced backpressure-driven flow. In this work, an assessment of the finite reservoir size effect on electroosmotic flows is presented theoretically and experimentally. A model is developed to describe the timedependent electrokinetic flow with finite reservoir size effects. The theoretical analysis shows that under certain conditions the finite reservoir size effect is significant. The important parameters that describe the effect of finite reservoir size on the flow characteristics are discussed. A new concept denoted as 'effective pumping period' is introduced to characterize the reservoir size effect. The proposed model clearly identifies the mechanisms of the finitereservoir size effects and is further confirmed by using micro-PIV technique. The results of this study can be used for facilitating the design of microfluidic devices

  17. Comparative SAXS and DSC study on stratum corneum structural organization in an epidermal cell culture model (ROC)

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Herre, Angela; Fahr, Alfred

    2013-01-01

    barrier similar to that of human stratum corneum is, however, a prerequisite. In this study, the stratum corneum lipid organization in an epidermal cell culture model based on rat epidermal keratinocytes (REK organotypic culture, ROC) was investigated by small-angle X-ray scattering (SAXS) in dependence......Cell cultured skin equivalents present an alternative for dermatological in vitro evaluations of drugs and excipients as they provide the advantage of availability, lower variability and higher assay robustness compared to native skin. For penetration/permeation studies, an adequate stratum corneum...... and SC lipid organization. Cultivation for 21days resulted in further minor changes in the structural organization of ROC SC. The SAXS patterns of ROC SC had overall large similarities with that of human SC and point to the presence of a long periodicity phase with a repeat distance of about 122Å, e...

  18. ROC generated thresholds for field-assessed aerobic fitness related to body size and cardiometabolic risk in schoolchildren.

    Directory of Open Access Journals (Sweden)

    Lynne M Boddy

    Full Text Available OBJECTIVES: 1. to investigate whether 20 m multi-stage shuttle run performance (20mSRT, an indirect measure of aerobic fitness, could discriminate between healthy and overweight status in 9-10.9 yr old schoolchildren using Receiver Operating Characteristic (ROC analysis; 2. Investigate if cardiometabolic risk differed by aerobic fitness group by applying the ROC cut point to a second, cross-sectional cohort. DESIGN: Analysis of cross-sectional data. PARTICIPANTS: 16,619 9-10.9 year old participants from SportsLinx project and 300 11-13.9 year old participants from the Welsh Schools Health and Fitness Study. OUTCOME MEASURES: SportsLinx; 20mSRT, body mass index (BMI, waist circumference, subscapular and superilliac skinfold thicknesses. Welsh Schools Health and Fitness Study; 20mSRT performance, waist circumference, and clustered cardiometabolic risk. ANALYSES: Three ROC curve analyses were completed, each using 20mSRT performance with ROC curve 1 related to BMI, curve 2 was related to waist circumference and 3 was related to skinfolds (estimated % body fat. These were repeated for both girls and boys. The mean of the three aerobic fitness thresholds was retained for analysis. The thresholds were subsequently applied to clustered cardiometabolic risk data from the Welsh Schools study to assess whether risk differed by aerobic fitness group. RESULTS: The diagnostic accuracy of the ROC generated thresholds was higher than would be expected by chance (all models AUC >0.7. The mean thresholds were 33 and 25 shuttles for boys and girls respectively. Participants classified as 'fit' had significantly lower cardiometabolic risk scores in comparison to those classed as unfit (p<0.001. CONCLUSION: The use of the ROC generated cut points by health professionals, teachers and coaches may provide the opportunity to apply population level 'risk identification and stratification' processes and plan for "at-risk" children to be referred onto intervention

  19. Advances in photonic reservoir computing

    Science.gov (United States)

    Van der Sande, Guy; Brunner, Daniel; Soriano, Miguel C.

    2017-05-01

    We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir's complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  20. Encapsulated microsensors for reservoir interrogation

    Science.gov (United States)

    Scott, Eddie Elmer; Aines, Roger D.; Spadaccini, Christopher M.

    2016-03-08

    In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

  1. All-optical reservoir computing.

    Science.gov (United States)

    Duport, François; Schneider, Bendix; Smerieri, Anteo; Haelterman, Marc; Massar, Serge

    2012-09-24

    Reservoir Computing is a novel computing paradigm that uses a nonlinear recurrent dynamical system to carry out information processing. Recent electronic and optoelectronic Reservoir Computers based on an architecture with a single nonlinear node and a delay loop have shown performance on standardized tasks comparable to state-of-the-art digital implementations. Here we report an all-optical implementation of a Reservoir Computer, made of off-the-shelf components for optical telecommunications. It uses the saturation of a semiconductor optical amplifier as nonlinearity. The present work shows that, within the Reservoir Computing paradigm, all-optical computing with state-of-the-art performance is possible.

  2. On the analysis of glycomics mass spectrometry data via the regularized area under the ROC curve

    Directory of Open Access Journals (Sweden)

    Lebrilla Carlito B

    2007-12-01

    Full Text Available Abstract Background Novel molecular and statistical methods are in rising demand for disease diagnosis and prognosis with the help of recent advanced biotechnology. High-resolution mass spectrometry (MS is one of those biotechnologies that are highly promising to improve health outcome. Previous literatures have identified some proteomics biomarkers that can distinguish healthy patients from cancer patients using MS data. In this paper, an MS study is demonstrated which uses glycomics to identify ovarian cancer. Glycomics is the study of glycans and glycoproteins. The glycans on the proteins may deviate between a cancer cell and a normal cell and may be visible in the blood. High-resolution MS has been applied to measure relative abundances of potential glycan biomarkers in human serum. Multiple potential glycan biomarkers are measured in MS spectra. With the objection of maximizing the empirical area under the ROC curve (AUC, an analysis method was considered which combines potential glycan biomarkers for the diagnosis of cancer. Results Maximizing the empirical AUC of glycomics MS data is a large-dimensional optimization problem. The technical difficulty is that the empirical AUC function is not continuous. Instead, it is in fact an empirical 0–1 loss function with a large number of linear predictors. An approach was investigated that regularizes the area under the ROC curve while replacing the 0–1 loss function with a smooth surrogate function. The constrained threshold gradient descent regularization algorithm was applied, where the regularization parameters were chosen by the cross-validation method, and the confidence intervals of the regression parameters were estimated by the bootstrap method. The method is called TGDR-AUC algorithm. The properties of the approach were studied through a numerical simulation study, which incorporates the positive values of mass spectrometry data with the correlations between measurements within person

  3. Non-localization and localization ROC analyses using clinically based scoring

    Science.gov (United States)

    Paquerault, Sophie; Samuelson, Frank W.; Myers, Kyle J.; Smith, Robert C.

    2009-02-01

    We are investigating the potential for differences in study conclusions when assessing the estimated impact of a computer-aided detection (CAD) system on readers' performance. The data utilized in this investigation were derived from a multi-reader multi-case observer study involving one hundred mammographic background images to which fixed-size and fixed-intensity Gaussian signals were added, generating a low- and high-intensity signal sets. The study setting allowed CAD assessment in two situations: when CAD sensitivity was 1) superior or 2) lower than the average reader. Seven readers were asked to review each set in the unaided and CAD-aided reading modes, mark and rate their findings. Using this data, we studied the effect on study conclusion of three clinically-based receiver operating characteristic (ROC) scoring definitions. These scoring definitions included both location-specific and non-location-specific rules. The results showed agreement in the estimated impact of CAD on the overall reader performance. In the study setting where CAD sensitivity is superior to the average reader, the mean difference in AUC between the CAD-aided read and unaided read was 0.049 (95%CIs: -0.027; 0.130) for the image scoring definition that is based on non-location-specific rules, and 0.104 (95%CIs: 0.036; 0.174) and 0.090 (95%CIs: 0.031; 0.155) for image scoring definitions that are based on location-specific rules. The increases in AUC were statistically significant for the location-specific scoring definitions. It was further observed that the variance on these estimates was reduced when using the location-specific scoring definitions compared to that using a non-location-specific scoring definition. In the study setting where CAD sensitivity is equivalent or lower than the average reader, the mean differences in AUC are slightly above 0.01 for all image scoring definitions. These increases in AUC were not statistical significant for any of the image scoring definitions

  4. The World of Virtual Exhibitions

    Directory of Open Access Journals (Sweden)

    Irena Eiselt

    2013-09-01

    Full Text Available EXTENDED ABSTRACTSpecial collections of the National and University Library (NUK hide a lot of items of precious value. The Slovenian cultural heritage is stored on paper or on other media as a part of the library’s Manuscripts, Incunabula and Rare Books Collection, Old Prints Collection, Maps and Pictorial Collection, Music Collection, Ephemera Collection, Serials Collection, and Slovenian Diaspora Publications Collection. Only a small part of the treasures is temporary revealed to the public on special exhibitions. The idea of virtual exhibitions of library treasures was born in 2005. The library aimed to exhibit precious items of special collections of high historical or artistic value. In 2008 the first two virtual exhibitions were created in-house offering access to the rich collections of old postcards of Ljubljana at the beginning of 20th century kept in the Maps and Pictorial Collection of NUK. They were soon followed by other virtual exhibitions. At the beginning they were organised in the same way as physical exhibitions, afterwards different programs were used for creation of special effects (for ex. 3D wall. About two years ago it was decided that the creation of virtual exhibitions will be simplified. Files of digitised and borndigital library materials in jpg format are imported to MS PowerPoint 2010. Each jpg file is now formatted by adding a frame, a description … to the slides which are saved as jpg files. The last step is the import of jpg files into Cooliris application used for NUK web exhibitions. In the paper the virtual exhibition design and creation, the technical point of view and criteria for the selection of exhibition content are explained following the example of the virtual exhibitions the Old Postcards of Ljubljana, Photo Ateliers in Slovenia, a collection of photographs Four Seasons by Fran Krašovec and photos of Post-Earthquake Ljubljana in 1895.

  5. Comparing risk of failure models in water supply networks using ROC curves

    International Nuclear Information System (INIS)

    Debon, A.; Carrion, A.; Cabrera, E.; Solano, H.

    2010-01-01

    The problem of predicting the failure of water mains has been considered from different perspectives and using several methodologies in engineering literature. Nowadays, it is important to be able to accurately calculate the failure probabilities of pipes over time, since water company profits and service quality for citizens depend on pipe survival; forecasting pipe failures could have important economic and social implications. Quantitative tools (such as managerial or statistical indicators and reliable databases) are required in order to assess the current and future state of networks. Companies managing these networks are trying to establish models for evaluating the risk of failure in order to develop a proactive approach to the renewal process, instead of using traditional reactive pipe substitution schemes. The main objective of this paper is to compare models for evaluating the risk of failure in water supply networks. Using real data from a water supply company, this study has identified which network characteristics affect the risk of failure and which models better fit data to predict service breakdown. The comparison using the receiver operating characteristics (ROC) graph leads us to the conclusion that the best model is a generalized linear model. Also, we propose a procedure that can be applied to a pipe failure database, allowing the most appropriate decision rule to be chosen.

  6. [Multiple linear regression and ROC curve analysis of the factors of lumbar spine bone mineral density].

    Science.gov (United States)

    Zhang, Xiaodong; Zhao, Yinxia; Hu, Shaoyong; Hao, Shuai; Yan, Jiewen; Zhang, Lingyan; Zhao, Jing; Li, Shaolin

    2015-09-01

    To investigate the correlation between the lumbar vertebra bone mineral density (BMD) and age, gender, height, weight, body mass index, waistline, hipline, bone marrow and abdomen fat, and to explore the key factor affecting the BMD. A total of 72 cases were randomly recruited. All the subjects underwent a spectroscopic examination of the third lumber vertebra with single-voxel method in 1.5T MR. Lipid fractions (FF%) were measured. Quantitative CT were also performed to get the BMD of L3 and the corresponding abdomen subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). The statistical analysis were performed by SPSS 19.0. Multiple linear regression showed except the age and FF% showed significant difference (P0.05). The correlation of age and FF% with BMD was statistically negatively significant (r=-0.830, -0.521, P<0.05). The ROC curve analysis showed that the sensitivety and specificity of predicting osteoporosis were 81.8% and 86.9%, with a threshold of 58.5 years old. And it showed that the sensitivety and specificity of predicting osteoporosis were 90.9% and 55.7%, with a threshold of 52.8% for FF%. The lumbar vertebra BMD was significantly and negatively correlated with age and bone marrow FF%, but it was not significantly correlated with gender, height, weight, BMI, waistline, hipline, SAT and VAT. And age was the critical factor.

  7. Comparing risk of failure models in water supply networks using ROC curves

    Energy Technology Data Exchange (ETDEWEB)

    Debon, A., E-mail: andeau@eio.upv.e [Centro de Gestion de la Calidad y del Cambio, Dpt. Estadistica e Investigacion Operativa Aplicadas y Calidad, Universidad Politecnica de Valencia, E-46022 Valencia (Spain); Carrion, A. [Centro de Gestion de la Calidad y del Cambio, Dpt. Estadistica e Investigacion Operativa Aplicadas y Calidad, Universidad Politecnica de Valencia, E-46022 Valencia (Spain); Cabrera, E. [Dpto. De Ingenieria Hidraulica Y Medio Ambiente, Instituto Tecnologico del Agua, Universidad Politecnica de Valencia, E-46022 Valencia (Spain); Solano, H. [Universidad Diego Portales, Santiago (Chile)

    2010-01-15

    The problem of predicting the failure of water mains has been considered from different perspectives and using several methodologies in engineering literature. Nowadays, it is important to be able to accurately calculate the failure probabilities of pipes over time, since water company profits and service quality for citizens depend on pipe survival; forecasting pipe failures could have important economic and social implications. Quantitative tools (such as managerial or statistical indicators and reliable databases) are required in order to assess the current and future state of networks. Companies managing these networks are trying to establish models for evaluating the risk of failure in order to develop a proactive approach to the renewal process, instead of using traditional reactive pipe substitution schemes. The main objective of this paper is to compare models for evaluating the risk of failure in water supply networks. Using real data from a water supply company, this study has identified which network characteristics affect the risk of failure and which models better fit data to predict service breakdown. The comparison using the receiver operating characteristics (ROC) graph leads us to the conclusion that the best model is a generalized linear model. Also, we propose a procedure that can be applied to a pipe failure database, allowing the most appropriate decision rule to be chosen.

  8. Film-screen vs. digital radiography in rheumatoid arthritis of the hand. An ROC analysis

    International Nuclear Information System (INIS)

    Jonsson, A.; Borg, A.; Hannesson, P.; Herrlin, K.; Jonsson, K.; Sloth, M.; Pettersson, H.

    1994-01-01

    In a prospective investigation the diagnostic accuracy of filmscreen and digital radiography in rheumatoid arthritis of hands was compared. Seventy hands of 36 patients with established rheumatoid arthritis were included in the study. Each of 11 joints in every hand was evaluated regarding the following radiologic parameters: soft tissue swelling, joint space narrowing, erosions and periarticular osteopenia. The digital images were obtained with storage phosphor image plates and evaluated in 2 forms; as digital hard-copy on film and on a monitor of an interactive workstation. The digital images had a resolution of either 3.33 or 5.0 lp/mm. ROC curves were constructed and comparing the area under the curves no significant difference was found between the 3 different imaging forms in either resolution group for soft tissue swelling, joint space narrowing and erosions. The film-screen image evaluation of periarticular osteopenia was significantly better than the digital hard-copy one in the 3.33 lp/mm resolution group, but no significant difference was found in the 5.0 lp/mm group. These results support the view that currently available digital systems are capable of adequate diagnostic performance. (orig.)

  9. PROMETHEE-ROC Model for Assessing the Readiness of Technology for Generating Energy

    Directory of Open Access Journals (Sweden)

    Danielle Costa Morais

    2015-01-01

    Full Text Available This paper puts forward a proposal for a multicriteria decision model for prioritizing technologies that are critical for power generation in the energy sector. It deals with the context of imprecise information regarding importance of criteria; then an integration of surrogate weights with the PROMETHEE method is undertaken in order to approach this context. In this type of strategic decision problem, how to deal with imprecise information is always a challenge. The use of surrogate weights presents a significant contribution and it can facilitate the assignment of weights in a decision ranking problem, which requires the decision-maker (DM to order the criteria by their importance for the decision problem. Thus for this situation of assessing the readiness of technology for generating energy where the DM is able and feels comfortable to order all criteria by their relative importance, the proposed approach of surrogate weights in the PROMETHEE II method, the PROMETHEE-ROC model, is shown to be an adequate approach.

  10. Joint confidence region estimation for area under ROC curve and Youden index.

    Science.gov (United States)

    Yin, Jingjing; Tian, Lili

    2014-03-15

    In the field of diagnostic studies, the area under the ROC curve (AUC) serves as an overall measure of a biomarker/diagnostic test's accuracy. Youden index, defined as the overall correct classification rate minus one at the optimal cut-off point, is another popular index. For continuous biomarkers of binary disease status, although researchers mainly evaluate the diagnostic accuracy using AUC, for the purpose of making diagnosis, Youden index provides an important and direct measure of the diagnostic accuracy at the optimal threshold and hence should be taken into consideration in addition to AUC. Furthermore, AUC and Youden index are generally correlated. In this paper, we initiate the idea of evaluating diagnostic accuracy based on AUC and Youden index simultaneously. As the first step toward this direction, this paper only focuses on the confidence region estimation of AUC and Youden index for a single marker. We present both parametric and non-parametric approaches for estimating joint confidence region of AUC and Youden index. We carry out extensive simulation study to evaluate the performance of the proposed methods. In the end, we apply the proposed methods to a real data set. Copyright © 2013 John Wiley & Sons, Ltd.

  11. Assessment of diagnostic value of tumor markers for colorectal neoplasm by logistic regression and ROC curve

    International Nuclear Information System (INIS)

    Ping, G.

    2007-01-01

    Full text: Objective: To assess the diagnostic value of CEA CA199 and CA50 for colorectal neoplasm by logistic regression and ROC curve. Methods: The subjects include 75 patients of colorectal cancer, 35 patients of benign intestinal disease and 49 health controls. CEA CA199 and CA50 are measured by CLIA ECLIA and IRMA respectively. The area under the curve (AUC) of CEA CA 199 CA50 and logistic regression results are compared. [Result] In the cancer-benign group, the AUC of CA50 is larger than the AUC of CA199 Compared with the AUC of combination of CEA CA199 and CA50 (0.604),the AUC of combination of CEA and CA50 (0.875) is larger and it is also larger than any other AUC of CEA CA199 or CA50 alone. In the cancerhealth group, the AUC of combination of CEA CA199 and CA50 is larger than any other AUC of CEA CA199 or CA50 alone. No matter in the cancer-benign group or cancerhealth group. The AUC of CEA is larger than the AUC of CA199 or CA50. Conclusion: CEA is useful in the diagnosis of colorectal cancer. In the process of differential diagnosis, the combination of CEA and CA50 can give more information, while the combination of three tumor markers does not perform well. Furthermore, as a statistical method, logistic regression can improve the diagnostic sensitivity and specificity. (author)

  12. An ROC study detecting ability of idiopathic pulmonary fibrosis using digital radiography

    International Nuclear Information System (INIS)

    Chung, Eun Chul; Im, Jung Gi; Han, Man Chung; Kim, Jong Hyo

    1991-01-01

    One potential advantage of the digital radiography system is its ability to enhance image quality by various types of processing. Digital unsharp masking is one of the simplest and most useful forms of enhancing processes. The efficacy of unsharp masking in radiological diagnosis has not been investigated thoroughly. To evaluate the effects of unsharp masking in film-digital chest images, 3 observers were shown 150 test radiographs. These test radiographs consisted of 50 unprocessed images (25 normals and 25 patients with idiopathic pulmonary fibrosis with honey combing) and their 100 processed images by using 450 and 15-sized masks respectively. An ROC analysis of these data suggests that unsharp masking is more effective in detecting idiopathic pulmonary fibrosis than unprocessed image (ρ < 0.05), and so it may improve diagnostic accuracy for interstitial fibrosis. In addition, the smaller mask size (15) is more effective than the larger one (mask size 45) (ρ < 0.05). By using this analytic approach, an optimal parameter in digital chest radiography may be investigated in many other forms of pulmonary disease such as pulmonary nodule or mediastinal mass

  13. The status of hazardous waste management in Taiwan, R.O.C

    International Nuclear Information System (INIS)

    Chen, L.L.G.

    1989-01-01

    A large quantity of industrial waste (such as waste oils FCB's, cadmium, etc.) is produced daily in Taiwan, R.O.C.. A 1985 survey found that the amount of waste generated equalled approximately 30 million tons per year. Hazardous waste represents 9.7% of this total. Based on statistics from this same 1985 survey, 72% of the factories disposed of their waste without intermediate treatment. This paper reports that since most methods used for treatment of hazardous wastes were implemented incorrectly, the proper treatment of such waste has become the focal point of environmental protection in Taiwan. From July, 1987 the short-term program for industrial waste control has had as its first priority the control of toxic, infectious and corrosive hazardous waste. At the same time, a registration system for permission, reporting and results inspection for hazardous wastes is being developed. An industrial waste exchange and reclamation system is also being developed. It is predicted that a complete hazardous waste management program can be developed within the next four years

  14. A ROC-based feature selection method for computer-aided detection and diagnosis

    Science.gov (United States)

    Wang, Songyuan; Zhang, Guopeng; Liao, Qimei; Zhang, Junying; Jiao, Chun; Lu, Hongbing

    2014-03-01

    Image-based computer-aided detection and diagnosis (CAD) has been a very active research topic aiming to assist physicians to detect lesions and distinguish them from benign to malignant. However, the datasets fed into a classifier usually suffer from small number of samples, as well as significantly less samples available in one class (have a disease) than the other, resulting in the classifier's suboptimal performance. How to identifying the most characterizing features of the observed data for lesion detection is critical to improve the sensitivity and minimize false positives of a CAD system. In this study, we propose a novel feature selection method mR-FAST that combines the minimal-redundancymaximal relevance (mRMR) framework with a selection metric FAST (feature assessment by sliding thresholds) based on the area under a ROC curve (AUC) generated on optimal simple linear discriminants. With three feature datasets extracted from CAD systems for colon polyps and bladder cancer, we show that the space of candidate features selected by mR-FAST is more characterizing for lesion detection with higher AUC, enabling to find a compact subset of superior features at low cost.

  15. Cognitive Vulnerabilities and Depression in Young Adults: An ROC Curves Analysis.

    Science.gov (United States)

    Balsamo, Michela; Imperatori, Claudio; Sergi, Maria Rita; Belvederi Murri, Martino; Continisio, Massimo; Tamburello, Antonino; Innamorati, Marco; Saggino, Aristide

    2013-01-01

    Objectives and Methods. The aim of the present study was to evaluate, by means of receiver operating characteristic (ROC) curves, whether cognitive vulnerabilities (CV), as measured by three well-known instruments (the Beck Hopelessness Scale, BHS; the Life Orientation Test-Revised, LOT-R; and the Attitudes Toward Self-Revised, ATS-R), independently discriminate between subjects with different severities of depression. Participants were 467 young adults (336 females and 131 males), recruited from the general population. The subjects were also administered the Beck Depression Inventory-II (BDI-II). Results. Four first-order (BHS Optimism/Low Standard; BHS Pessimism; Generalized Self-Criticism; and LOT Optimism) and two higher-order factors (Pessimism/Negative Attitudes Toward Self, Optimism) were extracted using Principal Axis Factoring analysis. Although all first-order and second-order factors were able to discriminate individuals with different depression severities, the Pessimism factor had the best performance in discriminating individuals with moderate to severe depression from those with lower depression severity. Conclusion. In the screening of young adults at risk of depression, clinicians have to pay particular attention to the expression of pessimism about the future.

  16. An ROC study detecting ability of idiopathic pulmonary fibrosis using digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eun Chul; Im, Jung Gi; Han, Man Chung; Kim, Jong Hyo [College of Medicine, Ewha Womens University, Seoul (Korea, Republic of)

    1991-03-15

    One potential advantage of the digital radiography system is its ability to enhance image quality by various types of processing. Digital unsharp masking is one of the simplest and most useful forms of enhancing processes. The efficacy of unsharp masking in radiological diagnosis has not been investigated thoroughly. To evaluate the effects of unsharp masking in film-digital chest images, 3 observers were shown 150 test radiographs. These test radiographs consisted of 50 unprocessed images (25 normals and 25 patients with idiopathic pulmonary fibrosis with honey combing) and their 100 processed images by using 450 and 15-sized masks respectively. An ROC analysis of these data suggests that unsharp masking is more effective in detecting idiopathic pulmonary fibrosis than unprocessed image ({rho} < 0.05), and so it may improve diagnostic accuracy for interstitial fibrosis. In addition, the smaller mask size (15) is more effective than the larger one (mask size 45) ({rho} < 0.05). By using this analytic approach, an optimal parameter in digital chest radiography may be investigated in many other forms of pulmonary disease such as pulmonary nodule or mediastinal mass.

  17. Cesium reservoir and interconnective components

    International Nuclear Information System (INIS)

    1994-03-01

    The program objective is to demonstrate the technology readiness of a TFE (thermionic fuel element) suitable for use as the basic element in a thermionic reactor with electric power output in the 0.5 to 5.0 MW range. A thermionic converter must be supplied with cesium vapor for two reasons. Cesium atoms adsorbed on the surface of the emitter cause a reduction of the emitter work function to permit high current densities without excessive heating of the emitter. The second purpose of the cesium vapor is to provide space-charge neutralization in the emitter-collector gap so that the high current densities may flow across the gap unattenuated. The function of the cesium reservoir is to provide a source of cesium atoms, and to provide a reserve in the event that cesium is lost from the plasma by any mechanism. This can be done with a liquid cesium metal reservoir in which case it is heated to the desired temperature with auxiliary heaters. In a TFE, however, it is desirable to have the reservoir passively heated by the nuclear fuel. In this case, the reservoir must operate at a temperature intermediate between the emitter and the collector, ruling out the use of liquid reservoirs. Integral reservoirs contained within the TFE will produce cesium vapor pressures in the desired range at typical electrode temperatures. The reservoir material that appears to be the best able to meet requirements is graphite. Cesium intercalates easily into graphite, and the cesium pressure is insensitive to loading for a given intercalation stage. The goals of the cesium reservoir test program were to verify the performance of Cs-graphite reservoirs in the temperature-pressure range of interest to TFE operation, and to test the operation of these reservoirs after exposure to a fast neutron fluence corresponding to seven year mission lifetime. In addition, other materials were evaluated for possible use in the integral reservoir

  18. Beyond ROC Curvature: Strength Effects and Response Time Data Support Continuous-Evidence Models of Recognition Memory

    Science.gov (United States)

    Dube, Chad; Starns, Jeffrey J.; Rotello, Caren M.; Ratcliff, Roger

    2012-01-01

    A classic question in the recognition memory literature is whether retrieval is best described as a continuous-evidence process consistent with signal detection theory (SDT), or a threshold process consistent with many multinomial processing tree (MPT) models. Because receiver operating characteristics (ROCs) based on confidence ratings are…

  19. 77 FR 1707 - National Toxicology Program (NTP) Final Process for Preparation of the Report on Carcinogens (RoC)

    Science.gov (United States)

    2012-01-11

    ... the RoC. The process is available on the NTP Web site ( http://ntp.niehs.nih.gov/go/rocprocess ) or by... Counselors public meeting (76 FR 68461) on December 15, 2011 ( http://ntp.niehs.nih.gov/go/9741 ). The NTP... Web site ( http://ntp.niehs.nih.gov/go/rocprocess ) or by contacting Dr. Lunn (see ADDRESSES...

  20. Reservoir engineering and hydrogeology

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Summaries are included which show advances in the following areas: fractured porous media, flow in single fractures or networks of fractures, hydrothermal flow, hydromechanical effects, hydrochemical processes, unsaturated-saturated systems, and multiphase multicomponent flows. The main thrust of these efforts is to understand the movement of mass and energy through rocks. This has involved treating fracture rock masses in which the flow phenomena within both the fractures and the matrix must be investigated. Studies also address the complex coupling between aspects of thermal, hydraulic, and mechanical processes associated with a nuclear waste repository in a fractured rock medium. In all these projects, both numerical modeling and simulation, as well as field studies, were employed. In the theoretical area, a basic understanding of multiphase flow, nonisothermal unsaturated behavior, and new numerical methods have been developed. The field work has involved reservoir testing, data analysis, and case histories at a number of geothermal projects

  1. FRACTURED PETROLEUM RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Abbas Firoozabadi

    1999-06-11

    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly

  2. Reservoir sedimentation; a literature survey

    NARCIS (Netherlands)

    Sloff, C.J.

    1991-01-01

    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on

  3. Advances in photonic reservoir computing

    Directory of Open Access Journals (Sweden)

    Van der Sande Guy

    2017-05-01

    Full Text Available We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir’s complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  4. Effects of reservoir hydrology on reproduction by largemouth bass and spotted bass in Normandy Reservoir, Tennessee

    Science.gov (United States)

    Sammons, S.M.; Dorsey, L.G.; Bettoli, P.W.; Fiss, F.C.

    1999-01-01

    Age-O largemouth bass Micropterus salmoides and spotted bass M. punctulatus were collected from Normandy Reservoir, Tennessee, 1992-1996, to evaluate effects of reservoir hydrology and hatching of shad Dorosoma spp. on hatching and first-year growth and survival of these two species. Fish were collected in cove rotenone samples in early August and electrofishing samples biweekly throughout the summer; hatch dates and age-specific growth for both species were determined from cove samples with sagittal otoliths. Hatching of both species ranged from early April to early June. Initiation of largemouth bass spawning, but not spotted bass spawning, was positively related to the first day water levels achieved full pool. Mean hatch dates of both species were positively related to the first day of full pool. Timing of spawning for both species was not related to water temperature, Largemouth bass exhibited bimodal length-frequency distributions by midsummer in two wet years and length frequencies were unimodal in dry years; spotted bass always formed unimodal length-frequency distributions. When largemouth bass exhibited bimodal length distributions, earlier hatched fish grew faster than later hatched fish. Spotted bass grew at similar rates, regardless of hatch date, every year except during 1992 when later hatched fish grew faster than earlier hatched fish. Weekly survival of largemouth bass in their first summer was positively related to reservoir water level. First-year growth of both species was not directly affected by the timing of threadfin shad D. petenense or gizzard shad D. cepedianum hatching.

  5. Soybean yield in relation to distance from the Itaipu reservoir

    Science.gov (United States)

    de Faria, Rogério Teixeira; Junior, Ruy Casão; Werner, Simone Silmara; Junior, Luiz Antônio Zanão; Hoogenboom, Gerrit

    2016-07-01

    Crops close to small water bodies may exhibit changes in yield if the water mass causes significant changes in the microclimate of areas near the reservoir shoreline. The scientific literature describes this effect as occurring gradually, with higher intensity in the sites near the shoreline and decreasing intensity with distance from the reservoir. Experiments with two soybean cultivars were conducted during four crop seasons to evaluate soybean yield in relation to distance from the Itaipu reservoir and determine the effect of air temperature and water availability on soybean crop yield. Fifteen experimental sites were distributed in three transects perpendicular to the Itaipu reservoir, covering an area at approximately 10 km from the shoreline. The yield gradient between the site closest to the reservoir and the sites farther away in each transect did not show a consistent trend, but varied as a function of distance, crop season, and cultivar. This finding indicates that the Itaipu reservoir does not affect the yield of soybean plants grown within approximately 10 km from the shoreline. In addition, the variation in yield among the experimental sites was not attributed to thermal conditions because the temperature was similar within transects. However, the crop water availability was responsible for higher differences in yield among the neighboring experimental sites related to water stress caused by spatial variability in rainfall, especially during the soybean reproductive period in January and February.

  6. Photowalk Exhibition opens at Microcosm

    CERN Document Server

    Katarina Anthony

    2011-01-01

    The winning photographs from the 2010 Global Particle Physics Photowalk competition will go on display at Microcosm from 11 February to 2 April. The exhibition is part of a global photography event taking place over three continents, with Photowalk exhibitions opening simultaneously at Fermilab in the US, KEK in Japan and here at CERN.   DESY wire chamber - First place people's choice; second place global jury competition. Photographer: Hans-Peter Hildebrandt  If you were one of the 1,300 photography lovers who voted in last year’s Photowalk competition, this exhibition is your chance to see the winning entries in print. The exhibition will take place in the downstairs gallery of Microcosm, overlooking the garden. 15 photographs will be on display, with each of the laboratories that participated in Photowalk represented by their 3 winning entries. Among them will be the “people’s choice” sunburst photo of a particle detector at DESY (Photo 1), and...

  7. Activity optimization method in nuclear medicine: a comparison with roc analysis

    International Nuclear Information System (INIS)

    Perez Diaz, M.; Diaz Rizo, O.; Lopez, A.; Estevez Aparicio, E.; Roque Diaz, R.

    2006-01-01

    Full text of publication follows: A discriminant method for optimizing the administered activity is validated by comparison with R.O.C. curves. The method is tested in 21 SPECT studies, performed with a Cardiac phantom. Three different cold lesions (L1, L2 and L3) are placed in the myocardium-wall by pairs for each SPECT. Three activities (84 MBq, 37 MBq or 18.5 MBq) of Tc 99 m diluted in water are used as background. The discriminant analysis is used to select the parameters that characterize image quality among the measured variables in the obtained tomographic images. They are a group of Lesion-to-Background (L/B) and Signal-to-Noise (S/N) ratios. Two clusters with different image quality (p=0.021) are obtained following the measured variables. The first one contains the studies performed with 37 MBq and 84 MBq and the second one the studies made with 18.5 MBq. Cluster classifications constitute the dependent variable in the discriminant function. The ratios B/L1, B/L2 and B/L3 are the parameters able to construct the function with 100 % of cases correctly classified into the clusters. The value of 37 MBq is the lowest tested activity that permits good results for the L/B variables, without significant differences respect to 84 MBq (p>0.05). The result is coincident with the applied R.O.C.-analysis, in which 37 MBq permits the highest area under the curve and low false-positive and false-negative rates with significant differences respect to 18.5 MBq (p=0.008)

  8. The recent development of isotope and radiation application in Taiwan, ROC

    Energy Technology Data Exchange (ETDEWEB)

    Ting, Gann; Tsai, Zei-Tsan; Huang, Henton [Institute of Nuclear Energy Research, Lung-Tan, TW (China)

    1996-10-01

    The Institute of Nuclear Energy Research (INER) plays a vital role in both isotope and radiation application in Taiwan, ROC. For research and development of reactor-produced radioisotopes, both Sr-90/Y-90 and W-188/Re-188 generators for therapeutic application were emphasized. For production of cyclotron-produced radioisotopes, I-123, Tl-201, Ga-67, In-111, Co-67 and F-18 were generated using a TR-30/15 cyclotron with H{sup -}/D{sup -} 30MeV/15MeV and maximum beam current of 400{mu}A/150{mu}A. For preparation of radiopharmaceuticals, a number of organic ligands have been synthesized such as d,1-hexamethylpropyleneamine oxime (HMPAO), N- (S-benzoylmercaptoacetyl) triglycine (S-Bz-MAG{sub 3}), 2-alkoxyisobutylisonitrile and metaiodobenzylguanidine (MIBG) and octreotide. R/D and production of radiopharmaceuticals have been carried out in cooperation with domestic hospitals. Some research work related to target radiotherapeutic and radiopharmaceuticals has also been carried out with cooperation of domestic hospitals. The C-13 urea breath test (C-13-UBT) has been extensively studied clinically to investigate the prevalence of Helicobacter pylori infection. The detection of this bacteria in the stomach ulcer becomes very important in both diagnosis and therapy monitoring. There are three large Co-60 irradiation plant in Taiwan. The radiosterilization of medical devices has been used in Taiwan for more than 14 years. Besides INER conducted R/D on (1) radiosterilization study of porcine serum, (2) insect sterilization, (3) treatment of condensate microphone with gamma ray, and (4) radiation polymerization for industry and medical applications. In conclusion, the prospects of isotope and radiation applications in Taiwan are very promising and encouraging. The R/D and development of the applications will contribute technical, economic and social benefits to the society. (J.P.N.)

  9. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)

    2006-11-01

    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging

  10. Globe exhibit wins international acclaim

    CERN Multimedia

    Katarina Anthony

    2011-01-01

    The Globe’s “Universe of Particles” exhibition has recently received four prestigious awards for its avant-garde design. This external praise is great encouragement for the CERN exhibitions currently on the drawing board.   The Universe of Particles exhibition has won 4 awards for its avant-garde design. Back in 2008, the design company Atelier Brückner was presented with a challenge: to design the layout of a new permanent exhibition for CERN, one that would epitomize both the Organization and its research. The brief was concise but complex: the exhibit had to be symbolic of the Organization, use modern technology, engage and immerse visitors, and, preferably, use touch-screen technology. With the help of IArt, an interactive technology firm, and based on the content provided by CERN’s Education Group, Atelier Brückner developed the “Universe of Particles” exhibit as it is today. Its principal concept centred on the s...

  11. Greenhouse Earth: A Traveling Exhibition

    International Nuclear Information System (INIS)

    Booth, W.H.; Caesar, S.

    1992-09-01

    The Franklin Institute Science Museum provided an exhibit entitled the Greenhouse Earth: A Traveling Exhibition. This 3500 square-foot exhibit on global climate change was developed in collaboration with the Association of Science-Technology Centers. The exhibit opened at The Franklin Institute on February 14, 1992, welcoming 291,000 visitors over its three-month stay. During its three-year tour, Greenhouse Earth will travel to ten US cities, reaching two million visitors. Greenhouse Earth aims to deepen public understanding of the scientific issues of global warming and the conservation measures that can be taken to slow its effects. The exhibit features hands-on exhibitry, interactive computer programs and videos, a theater production, a ''demonstration cart,'' guided tours, and lectures. supplemental educational programs at the Institute included a teachers preview, a symposium on climate change, and a ''satellite field trip.'' The development of Greenhouse Earth included front-end and formative evaluation procedures. Evaluation includes interviews with visitors, prototypes, and summative surveys for participating museums. During its stay in Philadelphia, Greenhouse Earth was covered by the local and national press, with reviews in print and broadcast media. Greenhouse Earth is the first large-scale museum exhibit to address global climate change

  12. A Novel Method for Performance Analysis of Compartmentalized Reservoirs

    Directory of Open Access Journals (Sweden)

    Shahamat Mohammad Sadeq

    2016-05-01

    Full Text Available This paper presents a simple analytical model for performance analysis of compartmentalized reservoirs producing under Constant Terminal Rate (CTR and Constant Terminal Pressure (CTP. The model is based on the well-known material balance and boundary dominated flow equations and is written in terms of capacitance and resistance of a production and a support compartment. These capacitance and resistance terms account for a combination of reservoir parameters which enable the developed model to be used for characterizing such systems. In addition to considering the properties contrast between the two reservoir compartments, the model takes into account existence of transmissibility barriers with the use of resistance terms. The model is used to analyze production performance of unconventional reservoirs, where the multistage fracturing of horizontal wells effectively creates a Stimulated Reservoir Volume (SRV with an enhanced permeability surrounded by a non-stimulated region. It can also be used for analysis of compartmentalized conventional reservoirs. The analytical solutions provide type curves through which the controlling reservoirs parameters of a compartmentalized system can be estimated. The contribution of the supporting compartment is modeled based on a boundary dominated flow assumption. The transient behaviour of the support compartment is captured by application of “distance of investigation” concept. The model shows that depletion of the production and support compartments exhibit two unit slopes on a log-log plot of pressure versus time for CTR. For CTP, however, the depletions display two exponential declines. The depletion signatures are separated by transition periods, which depend on the contribution of the support compartment (i.e. transient or boundary dominated flow. The developed equations can be implemented easily in a spreadsheet application, and are corroborated with the use of a numerical simulation. The study

  13. Comparison of pressure transient response in intensely and sparsely fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Johns, R.T.

    1989-04-01

    A comprehensive analytical model is presented to study the pressure transient behavior of a naturally fractured reservoir with a continuous matrix block size distribution. Geologically realistic probability density functions of matrix block size are used to represent reservoirs of varying fracture intensity and uniformity. Transient interporosity flow is assumed and interporosity skin is incorporated. Drawdown and interference pressure transient tests are investigated. The results show distinctions in the pressure response from intensely and sparsely fractured reservoirs in the absence of interporosity skin. Also, uniformly and nonuniformly fractured reservoirs exhibit distinct responses, irrespective of the degree of fracture intensity. The pressure response in a nonuniformly fractured reservoir with large block size variability, approaches a nonfractured (homogeneous) reservoir response. Type curves are developed to estimate matrix block size variability and the degree of fracture intensity from drawdown and interference well tests.

  14. Receiver operating characteristic (ROC) curves and the definition of threshold levels to diagnose coronary artery disease on electrocardiographic stress testing. Part II: the use of ROC curves in the choice of electrocardiographic stress test markers of ischaemia.

    Science.gov (United States)

    Marazìa, Stefania; Barnabei, Luca; De Caterina, Raffaele

    2008-01-01

    A common problem in diagnostic medicine, when performing a diagnostic test, is to obtain an accurate discrimination between 'normal' cases and cases with disease, owing to the overlapping distributions of these populations. In clinical practice, it is exceedingly rare that a chosen cut point will achieve perfect discrimination between normal cases and those with disease, and one has to select the best compromise between sensitivity and specificity by comparing the diagnostic performance of different tests or diagnostic criteria available. Receiver operating characteristic (or receiver operator characteristic, ROC) curves allow systematic and intuitively appealing descriptions of the diagnostic performance of a test and a comparison of the performance of different tests or diagnostic criteria. This review will analyse the basic principles underlying ROC curves and their specific application to the choice of optimal parameters on exercise electrocardiographic stress testing. Part II will be devoted to the comparative analysis of various parameters derived from exercise stress testing for the diagnosis of underlying coronary artery disease.

  15. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    KAUST Repository

    Hussain, Maaruf; Saad, Bilal; Negara, Ardiansyah; Sun, Shuyu

    2017-01-01

    Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically

  16. Differences in microbial community composition between injection and production water samples of water flooding petroleum reservoirs

    Directory of Open Access Journals (Sweden)

    P. K. Gao

    2015-06-01

    Full Text Available Microbial communities in injected water are expected to have significant influence on those of reservoir strata in long-term water flooding petroleum reservoirs. To investigate the similarities and differences in microbial communities in injected water and reservoir strata, high-throughput sequencing of microbial partial 16S rRNA of the water samples collected from the wellhead and downhole of injection wells, and from production wells in a homogeneous sandstone reservoir and a heterogeneous conglomerate reservoir were performed. The results indicate that a small number of microbial populations are shared between the water samples from the injection and production wells in the sandstone reservoir, whereas a large number of microbial populations are shared in the conglomerate reservoir. The bacterial and archaeal communities in the reservoir strata have high concentrations, which are similar to those in the injected water. However, microbial population abundance exhibited large differences between the water samples from the injection and production wells. The number of shared populations reflects the influence of microbial communities in injected water on those in reservoir strata to some extent, and show strong association with the unique variation of reservoir environments.

  17. Receiver operating characteristic (ROC) curves and the definition of threshold levels to diagnose coronary artery disease on electrocardiographic stress testing. Part I: The use of ROC curves in diagnostic medicine and electrocardiographic markers of ischaemia.

    Science.gov (United States)

    Barnabei, Luca; Marazìa, Stefania; De Caterina, Raffaele

    2007-11-01

    A common problem in diagnostic medicine, when performing a diagnostic test, is to obtain an accurate discrimination between 'normal' cases and cases with disease, owing to the overlapping distributions of these populations. In clinical practice, it is exceedingly rare that a chosen cut point will achieve perfect discrimination between normal cases and those with disease, and one has to select the best compromise between sensitivity and specificity by comparing the diagnostic performance of different tests or diagnostic criteria available. Receiver operating characteristic (or receiver operator characteristic, ROC) curves allow systematic and intuitively appealing descriptions of the diagnostic performance of a test and a comparison of the performance of different tests or diagnostic criteria. This review will analyse the basic principles underlying ROC curves and their specific application to the choice of optimal parameters on exercise electrocardiographic (ECG) stress testing. Part I will focus on theoretical description and analysis along with reviewing the common problems related to the diagnosis of myocardial ischaemia by means of exercise ECG stress testing. Part II will be devoted to applying ROC curves to available diagnostic criteria through the analysis of ECG stress test parameters.

  18. Exhibition - Mathematics, A Beautiful Elsewhere

    CERN Multimedia

    2011-01-01

    From 21 October 2011 to 18 March 2012, the Fondation Cartier pour l’art contemporain will present the exhibition Mathematics: A Beautiful Elsewhere, an exhibition developed in association with the Institut des Hautes Études Scientifiques (IHÉS) and under the patronage of UNESCO. For this unprecedented event, the foundation invited mathematicians to work with artists with whom it has previously worked to create an exhibition that allows visitors to see, hear, do, interpret and think about mathematics. By bringing mathematics into its premises, the Fondation Cartier is itself undergoing the “sudden change of scenery” described by mathematician Alexandre Grothendieck. More information is available here. Fondation Cartier pour l’art contemporain 261, boulevard Raspail 75014 Paris http://fondation.cartier.com Private Visit For professors, researchers and all the staff of Mathematics departments...

  19. Design Techniques and Reservoir Simulation

    Directory of Open Access Journals (Sweden)

    Ahad Fereidooni

    2012-11-01

    Full Text Available Enhanced oil recovery using nitrogen injection is a commonly applied method for pressure maintenance in conventional reservoirs. Numerical simulations can be practiced for the prediction of a reservoir performance in the course of injection process; however, a detailed simulation might take up enormous computer processing time. In such cases, a simple statistical model may be a good approach to the preliminary prediction of the process without any application of numerical simulation. In the current work, seven rock/fluid reservoir properties are considered as screening parameters and those parameters having the most considerable effect on the process are determined using the combination of experimental design techniques and reservoir simulations. Therefore, the statistical significance of the main effects and interactions of screening parameters are analyzed utilizing statistical inference approaches. Finally, the influential parameters are employed to create a simple statistical model which allows the preliminary prediction of nitrogen injection in terms of a recovery factor without resorting to numerical simulations.

  20. The Characteristics of Spanish Reservoirs

    National Research Council Canada - National Science Library

    Armengol, J; Merce, R

    2003-01-01

    Sau Reservoir was first filled in 1963 in a middle stretch of the Ter River, as part of a multi-use scheme, including hydroelectric power, agricultural irrigation, domestic and industrial water supply...

  1. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    KAUST Repository

    Hussain, Maaruf

    2017-06-06

    Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically-induced fractures that connect the wellbore to a larger fracture surface area within the reservoir rock volume. Thus, accurate estimation of the stimulated reservoir volume (SRV) becomes critical for the reservoir performance simulation and production analysis. Micro-seismic events (MS) have been commonly used as a proxy to map out the SRV geometry, which could be erroneous because not all MS events are related to hydraulic fracture propagation. The case studies discussed here utilized a fully 3-D simulation approach to estimate the SRV. The simulation approach presented in this paper takes into account the real-time changes in the reservoir\\'s geomechanics as a function of fluid pressures. It is consisted of four separate coupled modules: geomechanics, hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive re-meshing. Reservoir stress condition, rock mechanical properties, and injected fluid pressure dictate how fracture elements could open or slide. Critical stress intensity factor was used as a fracture criterion governing the generation of new fractures or propagation of existing fractures and their directions. Our simulations were run on a Cray XC-40 HPC system. The studies outcomes proved the approach of using MS data as a proxy for SRV to be significantly flawed. Many of the observed stimulated natural fractures are stress related and very few that are closer to the injection field are connected. The situation is worsened in a highly laminated shale reservoir as the hydraulic fracture propagation is significantly hampered. High contrast in the in-situ stresses related strike-slip developed thereby shortens the extent of SRV. However, far field nature fractures that were not connected to

  2. Describing three-class task performance: three-class linear discriminant analysis and three-class ROC analysis

    Science.gov (United States)

    He, Xin; Frey, Eric C.

    2007-03-01

    Binary ROC analysis has solid decision-theoretic foundations and a close relationship to linear discriminant analysis (LDA). In particular, for the case of Gaussian equal covariance input data, the area under the ROC curve (AUC) value has a direct relationship to the Hotelling trace. Many attempts have been made to extend binary classification methods to multi-class. For example, Fukunaga extended binary LDA to obtain multi-class LDA, which uses the multi-class Hotelling trace as a figure-of-merit, and we have previously developed a three-class ROC analysis method. This work explores the relationship between conventional multi-class LDA and three-class ROC analysis. First, we developed a linear observer, the three-class Hotelling observer (3-HO). For Gaussian equal covariance data, the 3- HO provides equivalent performance to the three-class ideal observer and, under less strict conditions, maximizes the signal to noise ratio for classification of all pairs of the three classes simultaneously. The 3-HO templates are not the eigenvectors obtained from multi-class LDA. Second, we show that the three-class Hotelling trace, which is the figureof- merit in the conventional three-class extension of LDA, has significant limitations. Third, we demonstrate that, under certain conditions, there is a linear relationship between the eigenvectors obtained from multi-class LDA and 3-HO templates. We conclude that the 3-HO based on decision theory has advantages both in its decision theoretic background and in the usefulness of its figure-of-merit. Additionally, there exists the possibility of interpreting the two linear features extracted by the conventional extension of LDA from a decision theoretic point of view.

  3. Learning from Exhibitions: Chuck Close.

    Science.gov (United States)

    Johnson, Mark M.

    1998-01-01

    Discusses the artwork of Chuck Close, who is well known for his over-sized portraits of fellow artists and anonymous sitters, and the exhibition of his work that premiered at New York's Museum of Modern Art before traveling to other cities in the United States. (CMK)

  4. The role of scintimammography and mammography in recurrent breast cancer. Evaluation of their accuracy using ROC curves

    International Nuclear Information System (INIS)

    Kolasinska, A.D.; Buscombe, J.R.; Cwikla, J.B.; Hilson, A.J.W.; Holloway, B.; Parbhoo, S.P.; Davidson, T.

    2001-01-01

    With the increasing demand for breast conservation surgery, the probability of recurrent tumour within the breast increases. Traditionally x-ray mammography (XMM) was used to assess the post-surgical breast, but post-surgery and radiotherapy changes have reduced the accuracy of this method. Scintimammography (SMM) has also been proposed and appears to be more accurate than XMM. A total of 101 women received Tc99m MIBI SMM and 88 had a subsequent XMM. There were 142 sites suspected of loco-regional recurrence breast cancer. During the study the patients did not receive any treatment other then hormonotherapy. SMM was performed by the standard Diggles-Khalkhali method and XMM was performed using standard 2 views. Analysis was performed and the results of each type of imaging compared with histology. In the ROC curve analysis 5 points of certainty were used: from 1 being definitely normal to 5 being definitely cancer; grades 4 and 5 were counted as positive. The overall sensitivity value of SMM was 84% and specificity was 85%, compared with a sensitivity of 52% for XMM and a specificity of 84%. Analysis of areas under ROC curves provides statistically significant difference between SMM and XMM (p < 0.05). Combining the two tests did not significantly improve the diagnostic accuracy of sequence imaging over SMM. ROC curve analysis demonstrates that scintimammography should be the primary investigation in suspected local recurrence following breast conservation surgery. (author)

  5. EXPLOITATION AND OPTIMIZATION OF RESERVOIR PERFORMANCE IN HUNTON FORMATION, OKLAHOMA

    Energy Technology Data Exchange (ETDEWEB)

    Mohan Kelkar

    2002-03-31

    The West Carney Field in Lincoln County, Oklahoma is one of few newly discovered oil fields in Oklahoma. Although profitable, the field exhibits several unusual characteristics. These include decreasing water-oil ratios, decreasing gas-oil ratios, decreasing bottomhole pressures during shut-ins in some wells, and transient behavior for water production in many wells. This report explains the unusual characteristics of West Carney Field based on detailed geological and engineering analyses. We propose a geological history that explains the presence of mobile water and oil in the reservoir. The combination of matrix and fractures in the reservoir explains the reservoir's flow behavior. We confirm our hypothesis by matching observed performance with a simulated model and develop procedures for correlating core data to log data so that the analysis can be extended to other, similar fields where the core coverage may be limited.

  6. A rationale for reservoir management economics

    International Nuclear Information System (INIS)

    Hickman, T.S.

    1995-01-01

    Significant economic benefits can be derived from the application f reservoir management. The key elements in economical reservoir management are the efficient use of available resources and optimization of reservoir exploitation through a multidisciplined approach. This paper describes various aspects of and approaches to reservoir management and provides case histories that support the findings

  7. Enhanced characterization of reservoir hydrocarbon components using electromagnetic data attributes

    KAUST Repository

    Katterbauer, Klemens

    2015-12-23

    Advances in electromagnetic imaging techniques have led to the growing utilization of this technology for reservoir monitoring and exploration. These exploit the strong conductivity contrast between the hydrocarbon and water phases and have been used for mapping water front propagation in hydrocarbon reservoirs and enhancing the characterization of the reservoir formation. The conventional approach for the integration of electromagnetic data is to invert the data for saturation properties and then subsequently use the inverted properties as constraints in the history matching process. The non-uniqueness and measurement errors may however make this electromagnetic inversion problem strongly ill-posed, leading to potentially inaccurate saturation profiles. Another limitation of this approach is the uncertainty of Archie\\'s parameters in relating rock conductivity to water saturation, which may vary in the reservoir and are generally poorly known. We present an Ensemble Kalman Filter framework for efficiently integrating electromagnetic data into the history matching process and for simultaneously estimating the Archie\\'s parameters and the variance of the observation error of the electromagnetic data. We apply the proposed framework to a compositional reservoir model. We aim at assessing the relevance of EM data for estimating the different hydrocarbon components of the reservoir. The experimental results demonstrate that the individual hydrocarbon components are generally well matched, with nitrogen exhibiting the strongest improvement. The estimated observation error standard deviations are also within expected levels (between 5 and 10%), significantly contributing to the robustness of the proposed EM history matching framework. Archie\\'s parameter estimates approximate well the reference profile and assist in the accurate description of the electrical conductivity properties of the reservoir formation, hence leading to estimation accuracy improvements of around

  8. Enhanced characterization of reservoir hydrocarbon components using electromagnetic data attributes

    KAUST Repository

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2015-01-01

    Advances in electromagnetic imaging techniques have led to the growing utilization of this technology for reservoir monitoring and exploration. These exploit the strong conductivity contrast between the hydrocarbon and water phases and have been used for mapping water front propagation in hydrocarbon reservoirs and enhancing the characterization of the reservoir formation. The conventional approach for the integration of electromagnetic data is to invert the data for saturation properties and then subsequently use the inverted properties as constraints in the history matching process. The non-uniqueness and measurement errors may however make this electromagnetic inversion problem strongly ill-posed, leading to potentially inaccurate saturation profiles. Another limitation of this approach is the uncertainty of Archie's parameters in relating rock conductivity to water saturation, which may vary in the reservoir and are generally poorly known. We present an Ensemble Kalman Filter framework for efficiently integrating electromagnetic data into the history matching process and for simultaneously estimating the Archie's parameters and the variance of the observation error of the electromagnetic data. We apply the proposed framework to a compositional reservoir model. We aim at assessing the relevance of EM data for estimating the different hydrocarbon components of the reservoir. The experimental results demonstrate that the individual hydrocarbon components are generally well matched, with nitrogen exhibiting the strongest improvement. The estimated observation error standard deviations are also within expected levels (between 5 and 10%), significantly contributing to the robustness of the proposed EM history matching framework. Archie's parameter estimates approximate well the reference profile and assist in the accurate description of the electrical conductivity properties of the reservoir formation, hence leading to estimation accuracy improvements of around 15%.

  9. Mobile Technologies in Museum Exhibitions

    OpenAIRE

    Sandra Medić; Nataša Pavlović

    2014-01-01

    In order to be up–to–date and give visitors a memorable and unique experience, museums are including usage of digital technologies in their exhibitions. Even though museums in Serbia are very important part of tourism offer, they still have traditional settings that are poorly interpreted. The majority of them have a scientific and historical review which is unattractive for various target groups of visitors and for museums it’s important to continually try out new ways in interpretation of t...

  10. A New Exhibition in Microcosm

    CERN Document Server

    2000-01-01

    Sebastien Pelletier explains states of matter to an enthusiastic group of youngsters during the opening of a new exhibition in Microcosm last week. The Fun with Physics workshop will be offered to all 13-14 year olds in school groups visiting CERN this year. The new Microcosm contents have been developed in collaboration with the local teaching community, and cover particles and the forces that act between them.

  11. "Big Science" exhibition at Balexert

    CERN Multimedia

    2008-01-01

    CERN is going out to meet those members of the general public who were unable to attend the recent Open Day. The Laboratory will be taking its "Big Science" exhibition from the Globe of Science and Innovation to the Balexert shopping centre from 19 to 31 May 2008. The exhibition, which shows the LHC and its experiments through the eyes of a photographer, features around thirty spectacular photographs measuring 4.5 metres high and 2.5 metres wide. Welcomed and guided around the exhibition by CERN volunteers, shoppers at Balexert will also have the opportunity to discover LHC components on display and watch films. "Fun with Physics" workshops will be held at certain times of the day. Main hall of the Balexert shopping centre, ground floor, from 9.00 a.m. to 7.00 p.m. Monday to Friday and from 10 a.m. to 6 p.m. on the two Saturdays. Call for volunteers All members of the CERN personnel are invited to enrol as volunteers to help welcom...

  12. Mobile Technologies in Museum Exhibitions

    Directory of Open Access Journals (Sweden)

    Sandra Medić

    2014-10-01

    Full Text Available In order to be up–to–date and give visitors a memorable and unique experience, museums are including usage of digital technologies in their exhibitions. Even though museums in Serbia are very important part of tourism offer, they still have traditional settings that are poorly interpreted. The majority of them have a scientific and historical review which is unattractive for various target groups of visitors and for museums it’s important to continually try out new ways in interpretation of their settings. Because technology continues to rapidly change the way we communicate, cultural institutions should adapt to new ways of communication with their visitors. This paper examines mobile technologies that can be used in museums to give visitors a different experience and transfer the knowledge innovatively. In that way it will be presented the modern concept of presentation of museum exhibitions, focusing on usage of mobile devices through mobile applications and QR codes. The paper provides the broad understanding of usage mobile technologies in museum exhibitions with its advantages and limitations. The research results can help the museums management to improve interpretation and communication with visitors and enrich the visitor experience.

  13. Trophic State Evolution and Nutrient Trapping Capacity in a Transboundary Subtropical Reservoir: A 25-Year Study.

    Science.gov (United States)

    Cunha, Davi Gasparini Fernandes; Benassi, Simone Frederigi; de Falco, Patrícia Bortoletto; Calijuri, Maria do Carmo

    2016-03-01

    Artificial reservoirs have been used for drinking water supply, other human activities, flood control and pollution abatement worldwide, providing overall benefits to downstream water quality. Most reservoirs in Brazil were built during the 1970s, but their long-term patterns of trophic status, water chemistry, and nutrient removal are still not very well characterized. We aimed to evaluate water quality time series (1985-2010) data from the riverine and lacustrine zones of the transboundary Itaipu Reservoir (Brazil/Paraguay). We examined total phosphorus and nitrogen, chlorophyll a concentrations, water transparency, and phytoplankton density to look for spatial and temporal trends and correlations with trophic state evolution and nutrient retention. There was significant temporal and spatial water quality variation (P water quality and structure of the reservoir were mainly affected by one internal force (hydrodynamics) and one external force (upstream cascading reservoirs). Nutrient and chlorophyll a concentrations tended to be lower in the lacustrine zone and decreased over the 25-year timeframe. Reservoir operational features seemed to be limiting primary production and phytoplankton development, which exhibited a maximum density of 6050  org/mL. The relatively small nutrient concentrations in the riverine zone were probably related to the effect of the cascade reservoirs upstream of Itaipu and led to relatively low removal percentages. Our study suggested that water quality problems may be more pronounced immediately after the filling phase of the artificial reservoirs, associated with the initial decomposition of drowned vegetation at the very beginning of reservoir operation.

  14. Contemporary Developments in Cinema Exhibition

    OpenAIRE

    Hanson, Stuart

    2014-01-01

    he work offered for this PhD by Published Works charts the history of cinema exhibition in Britain from the late 1950s to the present. At the start of this period, cinemagoing as a form of public entertainment entered a long period of decline that was only arrested with the development and growth of multiplex cinemas in the 1980s and 1990s. Despite these changes, the feature film itself remained a culturally and commercially valuable artefact, though increasingly this meant the Hollywood fil...

  15. Collaborative virtual environments art exhibition

    Science.gov (United States)

    Dolinsky, Margaret; Anstey, Josephine; Pape, Dave E.; Aguilera, Julieta C.; Kostis, Helen-Nicole; Tsoupikova, Daria

    2005-03-01

    This panel presentation will exhibit artwork developed in CAVEs and discuss how art methodologies enhance the science of VR through collaboration, interaction and aesthetics. Artists and scientists work alongside one another to expand scientific research and artistic expression and are motivated by exhibiting collaborative virtual environments. Looking towards the arts, such as painting and sculpture, computer graphics captures a visual tradition. Virtual reality expands this tradition to not only what we face, but to what surrounds us and even what responds to our body and its gestures. Art making that once was isolated to the static frame and an optimal point of view is now out and about, in fully immersive mode within CAVEs. Art knowledge is a guide to how the aesthetics of 2D and 3D worlds affect, transform, and influence the social, intellectual and physical condition of the human body through attention to psychology, spiritual thinking, education, and cognition. The psychological interacts with the physical in the virtual in such a way that each facilitates, enhances and extends the other, culminating in a "go together" world. Attention to sharing art experience across high-speed networks introduces a dimension of liveliness and aliveness when we "become virtual" in real time with others.

  16. Cloud computing and Reservoir project

    International Nuclear Information System (INIS)

    Beco, S.; Maraschini, A.; Pacini, F.; Biran, O.

    2009-01-01

    The support for complex services delivery is becoming a key point in current internet technology. Current trends in internet applications are characterized by on demand delivery of ever growing amounts of content. The future internet of services will have to deliver content intensive applications to users with quality of service and security guarantees. This paper describes the Reservoir project and the challenge of a reliable and effective delivery of services as utilities in a commercial scenario. It starts by analyzing the needs of a future infrastructure provider and introducing the key concept of a service oriented architecture that combines virtualisation-aware grid with grid-aware virtualisation, while being driven by business service management. This article will then focus on the benefits and the innovations derived from the Reservoir approach. Eventually, a high level view of Reservoir general architecture is illustrated.

  17. Multilevel techniques for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour

    The subject of this thesis is the development, application and study of novel multilevel methods for the acceleration and improvement of reservoir simulation techniques. The motivation for addressing this topic is a need for more accurate predictions of porous media flow and the ability to carry...... Full Approximation Scheme) • Variational (Galerkin) upscaling • Linear solvers and preconditioners First, a nonlinear multigrid scheme in the form of the Full Approximation Scheme (FAS) is implemented and studied for a 3D three-phase compressible rock/fluids immiscible reservoir simulator...... is extended to include a hybrid strategy, where FAS is combined with Newton’s method to construct a multilevel nonlinear preconditioner. This method demonstrates high efficiency and robustness. Second, an improved IMPES formulated reservoir simulator is implemented using a novel variational upscaling approach...

  18. Reservoir effects in radiocarbon dating

    International Nuclear Information System (INIS)

    Head, M.J.

    1997-01-01

    Full text: The radiocarbon dating technique depends essentially on the assumption that atmospheric carbon dioxide containing the cosmogenic radioisotope 14 C enters into a state of equilibrium with all living material (plants and animals) as part of the terrestrial carbon cycle. Terrestrial reservoir effects occur when the atmospheric 14 C signal is diluted by local effects where systems depleted in 14 C mix with systems that are in equilibrium with the atmosphere. Naturally, this can occur with plant material growing close to an active volcano adding very old CO 2 to the atmosphere (the original 14 C has completely decayed). It can also occur in highly industrialised areas where fossil fuel derived CO 2 dilutes the atmospheric signal. A terrestrial reservoir effect can occur in the case of fresh water shells living in rivers or lakes where there is an input of ground water from springs or a raising of the water table. Soluble bicarbonate derived from the dissolution of very old limestone produces a 14 C dilution effect. Land snail shells and stream carbonate depositions (tufas and travertines) can be affected by a similar mechanism. Alternatively, in specific cases, these reservoir effects may not occur. This means that general interpretations assuming quantitative values for these terrestrial effects are not possible. Each microenvironment associated with samples being analysed needs to be evaluated independently. Similarly, the marine environment produces reservoir effects. With respect to marine shells and corals, the water depth at which carbonate growth occurs can significantly affect quantitative 14 C dilution, especially in areas where very old water is uplifted, mixing with top layers of water that undergo significant exchange with atmospheric CO 2 . Hence, generalisations with respect to the marine reservoir effect also pose problems. These can be exacerbated by the mixing of sea water with either terrestrial water in estuaries, or ground water where

  19. Receiver operating characteristic (ROC) curve for classification of {sup 18}F-NaF uptake on PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Valadares, Agnes Araujo, E-mail: agnesvaladares@me.com [Universidade de Sao Paulo (HC/FM/USP), SP (Brazil). Hospital das Clinicas. Fac. de Mediciana; Duarte, Paulo Schiavom; Ono, Carla Rachel; Coura-Filho, George Barberio; Sado, Heitor Naoki; Carvalho, Giovanna [Instituto do Cancer do Estado de Sao Paulo Octavio Frias de Oliveira (ICESP), Sao Paulo, SP (Brazil). Servico de Medicina Nuclear; Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Fac. de Medicina. Dept. de Radiologia e Oncologia

    2016-01-15

    Objective: To assess the cutoff values established by ROC curves to classify {sup 18}F-NaF uptake as normal or malignant. Materials and Methods: PET/CT images were acquired 1 hour after administration of 185 MBq of {sup 18}F-NaF. Volumes of interest (VOIs) were drawn on three regions of the skeleton as follows: proximal right humerus diaphysis (HD), proximal right femoral diaphysis (FD) and first vertebral body (VB1), in a total of 254 patients, totalling 762 VOIs. The uptake in the VOIs was classified as normal or malignant on the basis of the radiopharmaceutical distribution pattern and of the CT images. A total of 675 volumes were classified as normal and 52 were classified as malignant. Thirty-five VOIs classified as indeterminate or nonmalignant lesions were excluded from analysis. The standardized uptake value (SUV) measured on the VOIs were plotted on an ROC curve for each one of the three regions. The area under the ROC (AUC) as well as the best cutoff SUVs to classify the VOIs were calculated. The best cutoff values were established as the ones with higher result of the sum of sensitivity and specificity. Results: The AUCs were 0.933, 0.889 and 0.975 for UD, FD and VB1, respectively. The best SUV cutoffs were 9.0 (sensitivity: 73%; specificity: 99%), 8.4 (sensitivity: 79%; specificity: 94%) and 21.0 (sensitivity: 93%; specificity: 95%) for UD, FD and VB1, respectively. Conclusion: The best cutoff value varies according to bone region of analysis and it is not possible to establish one value for the whole body. (author)

  20. Not proper ROC curves as new tool for the analysis of differentially expressed genes in microarray experiments

    Directory of Open Access Journals (Sweden)

    Pistoia Vito

    2008-10-01

    Full Text Available Abstract Background Most microarray experiments are carried out with the purpose of identifying genes whose expression varies in relation with specific conditions or in response to environmental stimuli. In such studies, genes showing similar mean expression values between two or more groups are considered as not differentially expressed, even if hidden subclasses with different expression values may exist. In this paper we propose a new method for identifying differentially expressed genes, based on the area between the ROC curve and the rising diagonal (ABCR. ABCR represents a more general approach than the standard area under the ROC curve (AUC, because it can identify both proper (i.e., concave and not proper ROC curves (NPRC. In particular, NPRC may correspond to those genes that tend to escape standard selection methods. Results We assessed the performance of our method using data from a publicly available database of 4026 genes, including 14 normal B cell samples (NBC and 20 heterogeneous lymphomas (namely: 9 follicular lymphomas and 11 chronic lymphocytic leukemias. Moreover, NBC also included two sub-classes, i.e., 6 heavily stimulated and 8 slightly or not stimulated samples. We identified 1607 differentially expressed genes with an estimated False Discovery Rate of 15%. Among them, 16 corresponded to NPRC and all escaped standard selection procedures based on AUC and t statistics. Moreover, a simple inspection to the shape of such plots allowed to identify the two subclasses in either one class in 13 cases (81%. Conclusion NPRC represent a new useful tool for the analysis of microarray data.

  1. Understanding satellite-based monthly-to-seasonal reservoir outflow estimation as a function of hydrologic controls

    Science.gov (United States)

    Bonnema, Matthew; Sikder, Safat; Miao, Yabin; Chen, Xiaodong; Hossain, Faisal; Ara Pervin, Ismat; Mahbubur Rahman, S. M.; Lee, Hyongki

    2016-05-01

    Growing population and increased demand for water is causing an increase in dam and reservoir construction in developing nations. When rivers cross international boundaries, the downstream stakeholders often have little knowledge of upstream reservoir operation practices. Satellite remote sensing in the form of radar altimetry and multisensor precipitation products can be used as a practical way to provide downstream stakeholders with the fundamentally elusive upstream information on reservoir outflow needed to make important and proactive water management decisions. This study uses a mass balance approach of three hydrologic controls to estimate reservoir outflow from satellite data at monthly and annual time scales: precipitation-induced inflow, evaporation, and reservoir storage change. Furthermore, this study explores the importance of each of these hydrologic controls to the accuracy of outflow estimation. The hydrologic controls found to be unimportant could potentially be neglected from similar future studies. Two reservoirs were examined in contrasting regions of the world, the Hungry Horse Reservoir in a mountainous region in northwest U.S. and the Kaptai Reservoir in a low-lying, forested region of Bangladesh. It was found that this mass balance method estimated the annual outflow of both reservoirs with reasonable skill. The estimation of monthly outflow from both reservoirs was however less accurate. The Kaptai basin exhibited a shift in basin behavior resulting in variable accuracy across the 9 year study period. Monthly outflow estimation from Hungry Horse Reservoir was compounded by snow accumulation and melt processes, reflected by relatively low accuracy in summer and fall, when snow processes control runoff. Furthermore, it was found that the important hydrologic controls for reservoir outflow estimation at the monthly time scale differs between the two reservoirs, with precipitation-induced inflow being the most important control for the Kaptai

  2. Gypsy Field Project in Reservoir Characterization

    International Nuclear Information System (INIS)

    John P. Castagna; William J. Lamb; Carlos Moreno; Roger Young; Lynn Soreghan

    2006-01-01

    to make predictions other than by exhaustive trial and error. Alternatively, we use the approach of using principle component analysis to reduce the seismic data to a minimum number of significant attributes that explain the variation in the data. These are then correlated to rock properties in order to make predictions. Part II of the report describe our efforts in optimal attributes as applied to the Gypsy data. (3) High Resolution 3D Seismic Processing: When faced with the issue of testing the above methods on the Gypsy dataset, we realized that the 3D seismic data were not processed well and exhibited poor ties to well control. The data was reprocessed with surface consistent predictive deconvolution, muting of wide-angle reflections, min/max exclusion stacking, and F-XY deconvolution. After reprocessing, a good character match with synthetic seismograms was observed. This work was presented at the 2001 SEG Annual Meeting and is included as Part III of this report. (4) Reservoir Characterization Education: The Gypsy project has provided the data for a reservoir characterization module which was added to Depositional Systems and Stratigraphy, a course required for majors in Geology and Geophysics. This module is important because it introduces students to the relevance of sedimentary geology to applied, real-world problems. This work was presented at the Geological Society of America annual meeting (Part IV) and is described on the website for the course (Part V of the report)

  3. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)

    P. K. Pande

    1998-10-29

    Initial drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, must become a process of the past. Such efforts do not optimize reservoir development as they fail to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. These reservoirs are typically characterized by: o Large, discontinuous pay intervals o Vertical and lateral changes in reservoir properties o Low reservoir energy o High residual oil saturation o Low recovery efficiency

  4. Sedimentological and Geomorphological Effects of Reservoir Flushing: The Cachi Reservoir, Costa Rica, 1996

    DEFF Research Database (Denmark)

    Brandt, Anders; Swenning, Joar

    1999-01-01

    Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs......Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs...

  5. Enrico Fermi exhibition at CERN

    CERN Multimedia

    2002-01-01

    A touring exhibition celebrating the centenary of Enrico Fermi's birth in 1901 will be on display at CERN (Main Building, Mezzanine) from 12-27 September. You are cordially invited to the opening celebration on Thursday 12 September at 16:00 (Main Building, Council Chamber), which will include speechs from: Luciano Maiani Welcome and Introduction Arnaldo Stefanini Celebrating Fermi's Centenary in Documents and Pictures Antonino Zichichi The New 'Centro Enrico Fermi' at Via Panisperna Ugo Amaldi Fermi at Via Panisperna and the birth of Nuclear Medicine Jack Steinberger Fermi in Chicago Valentin Telegdi A Close-up of Fermi and the screening of a documentary video about Fermi: Scienziati a Pisa: Enrico Fermi (Scientists at Pisa: Enrico Fermi) created by Francesco Andreotti for La Limonaia from early film, photographs and sound recordings (In Italian, with English subtitles - c. 30 mins). This will be followed by an aperitif on the Mezz...

  6. Crows spontaneously exhibit analogical reasoning.

    Science.gov (United States)

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Prevention of Reservoir Interior Discoloration

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, K.F.

    2001-04-03

    Contamination is anathema in reservoir production. Some of the contamination is a result of welding and some appears after welding but existed before. Oxygen was documented to be a major contributor to discoloration in welding. This study demonstrates that it can be controlled and that some of the informal cleaning processes contribute to contamination.

  8. Nonlinear Multigrid for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour; Eskildsen, Klaus Langgren; Engsig-Karup, Allan Peter

    2016-01-01

    efficiency for a black-oil model. Furthermore, the use of the FAS method enables a significant reduction in memory usage compared with conventional techniques, which suggests new possibilities for improved large-scale reservoir simulation and numerical efficiency. Last, nonlinear multilevel preconditioning...

  9. 3D CT versus axial helical CT versus conventional tomography in the classification of acetabular fractures: A ROC analysis

    International Nuclear Information System (INIS)

    Kickuth, Ralph; Laufer, Ulf; Hartung, Guido; Gruening, Christian; Stueckle, Christoph; Kirchner, Johannes

    2002-01-01

    AIM: To assess the diagnostic power of three-dimensional computed tomography (3D CT), axial helical computed tomography (CT) and conventional tomography in the classification of acetabular fractures by interdisciplinary review. MATERIALS AND METHODS: Receiver operating characteristics (ROCs) were assessed for two radiologists and two surgeons blinded to the presence of acetabular fractures in an animal model (a total of 62 porcine hips, 40 of them with artificial acetabular fractures). Main target parameter was the diagnostic accuracy in the classification of the artificial fractures following Judet et al. RESULTS: ROC analysis for radiologists showed A z values of 0·83 for 3D CT, 0·81 for axial helical CT, and 0·78 for conventional tomography; differences between the three techniques were not significant (P = 0·46-0·73). A z values for the surgeons were 0·87 for 3D CT, 0·68 for axial helical CT, and 0·60 for conventional tomography; 3D CT was significantly better than axial helical CT (P = 0·01) and conventional tomography (P = 0·001). The differences between axial helical CT and conventional tomography were not significant (P = 0·37). CONCLUSION: Acetabular fractures are best classified by 3D CT, followed by axial helical CT and conventional tomography when assessed by surgeons. 3D CT did not provide any additional significant benefit in the classification performed by radiologists. Kickuth, R. et al. (2002)

  10. Plateletpheresis efficiency and mathematical correction of software-derived platelet yield prediction: A linear regression and ROC modeling approach.

    Science.gov (United States)

    Jaime-Pérez, José Carlos; Jiménez-Castillo, Raúl Alberto; Vázquez-Hernández, Karina Elizabeth; Salazar-Riojas, Rosario; Méndez-Ramírez, Nereida; Gómez-Almaguer, David

    2017-10-01

    Advances in automated cell separators have improved the efficiency of plateletpheresis and the possibility of obtaining double products (DP). We assessed cell processor accuracy of predicted platelet (PLT) yields with the goal of a better prediction of DP collections. This retrospective proof-of-concept study included 302 plateletpheresis procedures performed on a Trima Accel v6.0 at the apheresis unit of a hematology department. Donor variables, software predicted yield and actual PLT yield were statistically evaluated. Software prediction was optimized by linear regression analysis and its optimal cut-off to obtain a DP assessed by receiver operating characteristic curve (ROC) modeling. Three hundred and two plateletpheresis procedures were performed; in 271 (89.7%) occasions, donors were men and in 31 (10.3%) women. Pre-donation PLT count had the best direct correlation with actual PLT yield (r = 0.486. P Simple correction derived from linear regression analysis accurately corrected this underestimation and ROC analysis identified a precise cut-off to reliably predict a DP. © 2016 Wiley Periodicals, Inc.

  11. Stuck between a ROC and a hard place? Barriers to the take up of green energy in the UK

    International Nuclear Information System (INIS)

    Diaz-Rainey, Ivan; Ashton, John K.

    2008-01-01

    This paper examines the UK mechanisms for ensuring future investment in renewable energy through consumer adoption of green energy tariffs and the Renewable Obligation Certificate (ROC) system. Using a national survey and focus groups the stated willingness by UK customers to pay a premium for renewable or green energy and actual take up of such tariffs is assessed. Substantial differences between willingness to pay for and the adoption of green energy tariffs are reported. This disparity is linked to a range of factors including consumer confusion, lack of supply, complexities of constructing 'green source' tariffs under the ROC system and a lack of customer trust. It is concluded that the re-definition of the green energy market in favour of 'green source' tariffs, greater direct compliance with the Renewable Obligation by addressing supply constraints, and efforts in providing clearer information and choices for consumers via a compulsory green energy accreditation scheme are required if willing consumers' are to contribute to investment in renewable energy

  12. ROC [Receiver Operating Characteristics] study of maximum likelihood estimator human brain image reconstructions in PET [Positron Emission Tomography] clinical practice

    International Nuclear Information System (INIS)

    Llacer, J.; Veklerov, E.; Nolan, D.; Grafton, S.T.; Mazziotta, J.C.; Hawkins, R.A.; Hoh, C.K.; Hoffman, E.J.

    1990-10-01

    This paper will report on the progress to date in carrying out Receiver Operating Characteristics (ROC) studies comparing Maximum Likelihood Estimator (MLE) and Filtered Backprojection (FBP) reconstructions of normal and abnormal human brain PET data in a clinical setting. A previous statistical study of reconstructions of the Hoffman brain phantom with real data indicated that the pixel-to-pixel standard deviation in feasible MLE images is approximately proportional to the square root of the number of counts in a region, as opposed to a standard deviation which is high and largely independent of the number of counts in FBP. A preliminary ROC study carried out with 10 non-medical observers performing a relatively simple detectability task indicates that, for the majority of observers, lower standard deviation translates itself into a statistically significant detectability advantage in MLE reconstructions. The initial results of ongoing tests with four experienced neurologists/nuclear medicine physicians are presented. Normal cases of 18 F -- fluorodeoxyglucose (FDG) cerebral metabolism studies and abnormal cases in which a variety of lesions have been introduced into normal data sets have been evaluated. We report on the results of reading the reconstructions of 90 data sets, each corresponding to a single brain slice. It has become apparent that the design of the study based on reading single brain slices is too insensitive and we propose a variation based on reading three consecutive slices at a time, rating only the center slice. 9 refs., 2 figs., 1 tab

  13. EU Climate Change Exhibition Held

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>On April 25, the CPAFFC, the China-EU Association (CEUA) and the Delegation of the European Commission to China jointly held the opening ceremony for the EU Exhibition on Climate Change in the CPAFFC. He Luli, former vice chairperson of the NPC Standing Committee and honorary president of the CEUA, Jose Manuel Barroso, president of the European Commission, and Li Jianping, vice president of the CPAFFC, attended the opening ceremony and made speeches. Honorary President He Luli highly praised the achievements made by China and the EU in their longtime cooperation of mutual benefits in various fields including environmental protection. She said, for many years China and EU have both committed to the development of all-round strategic partnership and establishment of a multi-level mechanism of political dialogue. She expressed, with increasing enthusiasm the CEUA would continue to actively carry out nongovernmental exchanges between China and the EU, and promote cooperation between the two sides in the fields of economy, society, environmental protection, science and technology, culture, etc.

  14. 49 CFR 236.792 - Reservoir, equalizing.

    Science.gov (United States)

    2010-10-01

    ... Reservoir, equalizing. An air reservoir connected with and adding volume to the top portion of the equalizing piston chamber of the automatic brake valve, to provide uniform service reductions in brake pipe...

  15. Comparative water quality assessment between a young and a stabilized hydroelectric reservoir in Aliakmon River, Greece.

    Science.gov (United States)

    Samiotis, Georgios; Trikoilidou, Eleni; Tsikritzis, Lazaros; Amanatidou, Elisavet

    2018-03-20

    In this work, a comparative study on the water quality characteristics of two in-line water reservoirs (artificial lakes) in Aliakmon River (Western Macedonia, Greece) is performed. Polyfytos Reservoir and Ilarion Reservoir were created in 1975 and 2012 respectively, in order to serve the homonymous hydroelectric stations. In young artificial lakes, severe deterioration of water quality may occur; thus, the monitoring and assessment of their water quality characteristics and their statistical interpretation are of great importance. In order to evaluate any temporal or spatial variations and to characterize water quality of these two in-line water reservoirs, water quality data from measurements conducted from 2012 to 2015 were statistically processed and interpreted by using a modified National Sanitation Foundation water quality index (WQI). The water physicochemical characteristics of the two reservoirs were found to be generally within the legislation limits, with relatively small temporal and spatial variations. Although Polyfytos Reservoir showed no significant deviations of its water quality, Ilarion Reservoir exhibited deviations in total Kjeldahl nitrogen, nitrite nitrogen, total suspended solids, and turbidity due to the inundated vegetation decomposition. The conducted measurements and the use of the modified NSFWQI revealed that during the inundation period of Ilarion Reservoir, its water quality was "moderate" and that the deviations were softened through time, leading to "good" water quality during its maturation period. Three years since the creation of Ilarion Reservoir, water quality does not match that of Aliakmon River (feeding water) or that of the stabilized reservoir (Polyfytos Reservoir), whose quality is characterized as "high." The use of a WQI, such as the proposed modified NSFWQI, for evaluating water quality of each sampling site and of an entire water system proved to be a rapid and relatively accurate assessment tool.

  16. Applying a reservoir functional-zone paradigm to littoral bluegills: differences in length and catch frequency?

    Directory of Open Access Journals (Sweden)

    Nathan Ruhl

    2014-08-01

    Full Text Available Reservoirs exhibit gradients in conditions and resources along the transition from lotic to lentic habitat that may be important to bluegill ecology. The lotic–lentic gradient can be partitioned into three functional zones: the riverine, transitional, and lacustrine zones. We measured catch frequency and length of bluegills (Lepomis macrochirus captured along the periphery of these areas (i.e., in the littoral zone of each functional zone for four small reservoirs in Southeastern Ohio during the summer months of three years. Catch frequency differed between zones for two reservoirs, but these differences were not observed in other years. There was no relationship between reservoir zone and either standard length or catch frequency when the data for all reservoirs were pooled, but we did observe a bimodal length distribution in all reservoirs. A combination of ecological factors including inter and intraspecific competition, predation intensity, management practices, limnology, and assemblage complexity may be mitigating bluegill distribution and abundance in reservoirs. Therefore, a functional zone (categorical approach to understanding bluegill ecology in reservoirs may not be appropriate.

  17. RECENT ADVANCES IN NATURALLY FRACTURED RESERVOIR MODELING

    OpenAIRE

    ORDOÑEZ, A; PEÑUELA, G; IDROBO, E. A; MEDINA, C. E

    2001-01-01

    Large amounts of oil reserves are contained in naturally fractured reservoirs. Most of these hydrocarbon volumes have been left behind because of the poor knowledge and/or description methodology of those reservoirs. This lack of knowledge has lead to the nonexistence of good quantitative models for this complicated type of reservoirs. The complexity of naturally fractured reservoirs causes the need for integration of all existing information at all scales (drilling, well logging, seismic, we...

  18. Reservoir resistivity characterization incorporating flow dynamics

    KAUST Repository

    Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim; Katterbauer, Klemens

    2016-01-01

    Systems and methods for reservoir resistivity characterization are provided, in various aspects, an integrated framework for the estimation of Archie's parameters for a strongly heterogeneous reservoir utilizing the dynamics of the reservoir are provided. The framework can encompass a Bayesian estimation/inversion method for estimating the reservoir parameters, integrating production and time lapse formation conductivity data to achieve a better understanding of the subsurface rock conductivity properties and hence improve water saturation imaging.

  19. Reservoir resistivity characterization incorporating flow dynamics

    KAUST Repository

    Arango, Santiago

    2016-04-07

    Systems and methods for reservoir resistivity characterization are provided, in various aspects, an integrated framework for the estimation of Archie\\'s parameters for a strongly heterogeneous reservoir utilizing the dynamics of the reservoir are provided. The framework can encompass a Bayesian estimation/inversion method for estimating the reservoir parameters, integrating production and time lapse formation conductivity data to achieve a better understanding of the subsurface rock conductivity properties and hence improve water saturation imaging.

  20. Tenth workshop on geothermal reservoir engineering: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-22

    The workshop contains presentations in the following areas: (1) reservoir engineering research; (2) field development; (3) vapor-dominated systems; (4) the Geysers thermal area; (5) well test analysis; (6) production engineering; (7) reservoir evaluation; (8) geochemistry and injection; (9) numerical simulation; and (10) reservoir physics. (ACR)

  1. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Nurhandoko, Bagus Endar B., E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4" t" hfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia); Susilowati, E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Rock Fluid Imaging Lab., Bandung (Indonesia)

    2015-04-16

    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia.

  2. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    International Nuclear Information System (INIS)

    thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" data-affiliation=" (Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" >Nurhandoko, Bagus Endar B.; Susilowati

    2015-01-01

    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia

  3. EXPLOITATION AND OPTIMIZATION OF RESERVOIR PERFORMANCE IN HUNTON FORMATION, OKLAHOMA

    Energy Technology Data Exchange (ETDEWEB)

    Mohan Kelkar

    2005-02-01

    Hunton formation in Oklahoma has displayed some unique production characteristics. These include high initial water-oil and gas-oil ratios, decline in those ratios over time and temporary increase in gas-oil ratio during pressure build up. The formation also displays highly complex geology, but surprising hydrodynamic continuity. This report addresses three key issues related specifically to West Carney Hunton field and, in general, to any other Hunton formation exhibiting similar behavior: (1) What is the primary mechanism by which oil and gas is produced from the field? (2) How can the knowledge gained from studying the existing fields can be extended to other fields which have the potential to produce? (3) What can be done to improve the performance of this reservoir? We have developed a comprehensive model to explain the behavior of the reservoir. By using available production, geological, core and log data, we are able to develop a reservoir model which explains the production behavior in the reservoir. Using easily available information, such as log data, we have established the parameters needed for a field to be economically successful. We provide guidelines in terms of what to look for in a new field and how to develop it. Finally, through laboratory experiments, we show that surfactants can be used to improve the hydrocarbons recovery from the field. In addition, injection of CO{sub 2} or natural gas also will help us recover additional oil from the field.

  4. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    Directory of Open Access Journals (Sweden)

    Shams Bilal

    2017-08-01

    Full Text Available Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources.

  5. Simulation study of huff-n-puff air injection for enhanced oil recovery in shale oil reservoirs

    Directory of Open Access Journals (Sweden)

    Hu Jia

    2018-03-01

    Full Text Available This paper is the first attempt to evaluate huff-n-puff air injection in a shale oil reservoir using a simulation approach. Recovery mechanisms and physical processes of huff-n-puff air injection in a shale oil reservoir are investigated through investigating production performance, thermal behavior, reservoir pressure and fluid saturation features. Air flooding is used as the basic case for a comparative study. The simulation study suggests that thermal drive is the main recovery mechanism for huff-n-puff air injection in the shale oil reservoir, but not for simple air flooding. The synergic recovery mechanism of air flooding in conventional light oil reservoirs can be replicated in shale oil reservoirs by using air huff-n-puff injection strategy. Reducing huff-n-puff time is better for performing the synergic recovery mechanism of air injection. O2 diffusion plays an important role in huff-n-puff air injection in shale oil reservoirs. Pressure transmissibility as well as reservoir pressure maintenance ability in huff-n-puff air injection is more pronounced than the simple air flooding after primary depletion stage. No obvious gas override is exhibited in both air flooding and air huff-n-puff injection scenarios in shale reservoirs. Huff-n-puff air injection has great potential to develop shale oil reservoirs. The results from this work may stimulate further investigations.

  6. Glutamate dehydrogenase (RocG) in Bacillus licheniformis WX-02: Enzymatic properties and specific functions in glutamic acid synthesis for poly-γ-glutamic acid production.

    Science.gov (United States)

    Tian, Guangming; Wang, Qin; Wei, Xuetuan; Ma, Xin; Chen, Shouwen

    2017-04-01

    Poly-γ-glutamic acid (γ-PGA), a natural biopolymer, is widely used in cosmetics, medicine, food, water treatment, and agriculture owing to its features of moisture sequestration, cation chelation, non-toxicity and biodegradability. Intracellular glutamic acid, the substrate of γ-PGA, is a limiting factor for high yield in γ-PGA production. Bacillus subtilis and Bacillus licheniformis are both important γ-PGA producing strains, and B. subtilis synthesizes glutamic acid in vivo using the unique GOGAT/GS pathway. However, little is known about the glutamate synthesis pathway in B. licheniformis. The aim of this work was to characterize the glutamate dehydrogenase (RocG) in glutamic acid synthesis from B. licheniformis with both in vivo and in vitro experiments. By re-directing the carbon flux distribution, the rocG gene deletion mutant WX-02ΔrocG produced intracellular glutamic acid with a concentration of 90ng/log(CFU), which was only 23.7% that of the wild-type WX-02 (380ng/log(CFU)). Furthermore, the γ-PGA yield of mutant WX-02ΔrocG was 5.37g/L, a decrease of 45.3% compared to the wild type (9.82g/L). In vitro enzymatic assays of RocG showed that RocG has higher affinity for 2-oxoglutarate than glutamate, and the glutamate synthesis rate was far above degradation. This is probably the first study to reveal the glutamic acid synthesis pathway and the specific functions of RocG in B. licheniformis. The results indicate that γ-PGA production can be enhanced through improving intracellular glutamic acid synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. 4. International reservoir characterization technical conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    This volume contains the Proceedings of the Fourth International Reservoir Characterization Technical Conference held March 2-4, 1997 in Houston, Texas. The theme for the conference was Advances in Reservoir Characterization for Effective Reservoir Management. On March 2, 1997, the DOE Class Workshop kicked off with tutorials by Dr. Steve Begg (BP Exploration) and Dr. Ganesh Thakur (Chevron). Tutorial presentations are not included in these Proceedings but may be available from the authors. The conference consisted of the following topics: data acquisition; reservoir modeling; scaling reservoir properties; and managing uncertainty. Selected papers have been processed separately for inclusion in the Energy Science and Technology database.

  8. MIKROMITSETY- MIGRANTS IN MINGECHEVIR RESERVOIR

    Directory of Open Access Journals (Sweden)

    M. A. Salmanov

    2017-01-01

    Full Text Available Aim. It is hardly possible to predict the continued stability of the watercourse ecosystems without the study of biological characteristics and composition of organisms inhabiting them. In the last 35-40 years, environmental conditions of the Mingachevir reservoir are determined by the stationary anthropogenic pressure. It was found that such components of plankton as algae, bacteria and fungi play a leading role in the transformation and migration of pollutants. The role of the three groups of organisms is very important in maintaining the water quality by elimination of pollutants. Among the organisms inhabiting the Mingachevir Reservoir, micromycetes have not yet been studied. Therefore, the study of the species composition and seasonal dynamics, peculiarities of their growth and development in the environment with the presence of some of the pollutants should be considered to date.Methods. In order to determine the role of micromycetes-migrants in the mineralization of organic substrates, as an active participant of self-purification process, we used water samples from the bottom sediments as well as decaying and skeletonized stalks of cane, reeds, algae, macrophytes, exuvia of insects and fish remains submerged in water.Findings. For the first time, we obtained the data on the quality and quantity of microscopic mycelial fungi in freshwater bodies on the example of the Mingachevir water reservoir; we also studied the possibilities for oxygenating the autochthonous organic matter of allochthonous origin with micromycetes-migrants.Conclusions. It was found that the seasonal development of micromycetes-migrants within the Mingachevir reservoir is characterized by an increase in the number of species in the summer and a gradual reduction in species diversity in the fall. 

  9. Geothermal Reservoir Temperatures in Southeastern Idaho using Multicomponent Geothermometry

    Energy Technology Data Exchange (ETDEWEB)

    Neupane, Ghanashyam [Idaho National Lab. (INL) and Center for Advanced Energy Studies, Idaho Falls, ID (United States); Mattson, Earl D. [Idaho National Lab. (INL) and Center for Advanced Energy Studies, Idaho Falls, ID (United States); McLing, Travis L. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Center for Advanced Energy Studies; Palmer, Carl D. [Univ. of Idaho, Idaho Falls, ID (United States); Smith, Robert W. [Univ. of Idaho and Center for Advanced Energy Studies, Idaho Falls, ID (United States); Wood, Thomas R. [Univ. of Idaho and Center for Advanced Energy Studies, Idaho Falls, ID (United States); Podgorney, Robert K. [Idaho National Lab. (INL) and Center for Advanced Energy Studies, Idaho Falls, ID (United States)

    2015-03-01

    Southeastern Idaho exhibits numerous warm springs, warm water from shallow wells, and hot water within oil and gas test wells that indicate a potential for geothermal development in the area. Although the area exhibits several thermal expressions, the measured geothermal gradients vary substantially (19 – 61 ºC/km) within this area, potentially suggesting a redistribution of heat in the overlying ground water from deeper geothermal reservoirs. We have estimated reservoir temperatures from measured water compositions using an inverse modeling technique (Reservoir Temperature Estimator, RTEst) that calculates the temperature at which multiple minerals are simultaneously at equilibrium while explicitly accounting for the possible loss of volatile constituents (e.g., CO2), boiling and/or water mixing. Compositions of a selected group of thermal waters representing southeastern Idaho hot/warm springs and wells were used for the development of temperature estimates. The temperature estimates in the the region varied from moderately warm (59 ºC) to over 175 ºC. Specifically, hot springs near Preston, Idaho resulted in the highest temperature estimates in the region.

  10. Geothermal Reservoir Temperatures in Southeastern Idaho using Multicomponent Geothermometry

    International Nuclear Information System (INIS)

    Neupane, Ghanashyam; Mattson, Earl D.; McLing, Travis L.; Smith, Robert W.; Wood, Thomas R.; Podgorney, Robert K.

    2015-01-01

    Southeastern Idaho exhibits numerous warm springs, warm water from shallow wells, and hot water within oil and gas test wells that indicate a potential for geothermal development in the area. Although the area exhibits several thermal expressions, the measured geothermal gradients vary substantially (19 - 61 °C/km) within this area, potentially suggesting a redistribution of heat in the overlying ground water from deeper geothermal reservoirs. We have estimated reservoir temperatures from measured water compositions using an inverse modeling technique (Reservoir Temperature Estimator, RTEst) that calculates the temperature at which multiple minerals are simultaneously at equilibrium while explicitly accounting for the possible loss of volatile constituents (e.g., CO2), boiling and/or water mixing. Compositions of a selected group of thermal waters representing southeastern Idaho hot/warm springs and wells were used for the development of temperature estimates. The temperature estimates in the the region varied from moderately warm (59 °C) to over 175 °C. Specifically, hot springs near Preston, Idaho resulted in the highest temperature estimates in the region.

  11. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  12. Williston Reservoir raising - environmental overview

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    This preliminary environmental overview report was prepared by B.C. Hydro in June 1987 and revised in July 1988 as an initial assessment of a possible 1.5 m (5 ft.) raise in the Williston Reservoir maximum normal level. The enviromental overview study and the associated engineering and property studies were undertaken to provide information for a decision on whether to initiate more detailed studies. Overview studies are based mainly on available reports, mapping and field data, supplemented by limited site reconnaissance and, in this case, input from key agencies and groups. The lack of adequate mapping of areas which could be affected by reservoir raising did not permit definitive conclusion to be reached. This mapping will be done over the next year to complete the overview assessment. This document covers the impact assessment of socio-economic factors, forestry, reservoir clearing, heritage, recreation, aquatic resources, and wilflife. Further studies in each of these areas are also included. 54 refs., 11 figs., 8 tabs.

  13. Reservoir floodplains support distinct fish assemblages

    Science.gov (United States)

    Miranda, Leandro E.; Wigen, S. L.; Dagel, Jonah D.

    2014-01-01

    Reservoirs constructed on floodplain rivers are unique because the upper reaches of the impoundment may include extensive floodplain environments. Moreover, reservoirs that experience large periodic water level fluctuations as part of their operational objectives seasonally inundate and dewater floodplains in their upper reaches, partly mimicking natural inundations of river floodplains. In four flood control reservoirs in Mississippi, USA, we explored the dynamics of connectivity between reservoirs and adjacent floodplains and the characteristics of fish assemblages that develop in reservoir floodplains relative to those that develop in reservoir bays. Although fish species richness in floodplains and bays were similar, species composition differed. Floodplains emphasized fish species largely associated with backwater shallow environments, often resistant to harsh environmental conditions. Conversely, dominant species in bays represented mainly generalists that benefit from the continuous connectivity between the bay and the main reservoir. Floodplains in the study reservoirs provided desirable vegetated habitats at lower water level elevations, earlier in the year, and more frequently than in bays. Inundating dense vegetation in bays requires raising reservoir water levels above the levels required to reach floodplains. Therefore, aside from promoting distinct fish assemblages within reservoirs and helping promote diversity in regulated rivers, reservoir floodplains are valued because they can provide suitable vegetated habitats for fish species at elevations below the normal pool, precluding the need to annually flood upland vegetation that would inevitably be impaired by regular flooding. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  14. The role of reservoir characterization in the reservoir management process (as reflected in the Department of Energy`s reservoir management demonstration program)

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, M.L. [BDM-Petroleum Technologies, Bartlesville, OK (United States); Young, M.A.; Madden, M.P. [BDM-Oklahoma, Bartlesville, OK (United States)] [and others

    1997-08-01

    Optimum reservoir recovery and profitability result from guidance of reservoir practices provided by an effective reservoir management plan. Success in developing the best, most appropriate reservoir management plan requires knowledge and consideration of (1) the reservoir system including rocks, and rock-fluid interactions (i.e., a characterization of the reservoir) as well as wellbores and associated equipment and surface facilities; (2) the technologies available to describe, analyze, and exploit the reservoir; and (3) the business environment under which the plan will be developed and implemented. Reservoir characterization is the essential to gain needed knowledge of the reservoir for reservoir management plan building. Reservoir characterization efforts can be appropriately scaled by considering the reservoir management context under which the plan is being built. Reservoir management plans de-optimize with time as technology and the business environment change or as new reservoir information indicates the reservoir characterization models on which the current plan is based are inadequate. BDM-Oklahoma and the Department of Energy have implemented a program of reservoir management demonstrations to encourage operators with limited resources and experience to learn, implement, and disperse sound reservoir management techniques through cooperative research and development projects whose objectives are to develop reservoir management plans. In each of the three projects currently underway, careful attention to reservoir management context assures a reservoir characterization approach that is sufficient, but not in excess of what is necessary, to devise and implement an effective reservoir management plan.

  15. Análise TG-ROC de testes de imunofluorescência no diagnóstico de leishmaniose visceral canina Análisis TG-ROC de pruebas de inmunofluorescencia en el diagnóstico de leishmaniasis visceral canina TG-ROC analysis of immunofluorescence assays in canine visceral leishmaniasis diagnosis

    Directory of Open Access Journals (Sweden)

    Rita Maria da Silva

    2009-12-01

    Full Text Available OBJETIVO: Analisar a acurácia do diagnóstico de dois protocolos de imunofluorescência indireta para leishmaniose visceral canina. MÉTODOS: Cães provenientes de inquérito soroepidemiológico realizado em área endêmica nos municípios de Araçatuba e de Andradina, na região noroeste do estado de São Paulo, em 2003, e área não endêmica da região metropolitana de São Paulo, foram utilizados para avaliar comparativamente dois protocolos da reação de imunofluorescência indireta (RIFI para leishmaniose: um utilizando antígeno heterólogo Leishmania major (RIFI-BM e outro utilizando antígeno homólogo Leishmania chagasi (RIFI-CH. Para estimar acurácia utilizou-se a análise two-graph receiver operating characteristic (TG-ROC. A análise TG-ROC comparou as leituras da diluição 1:20 do antígeno homólogo (RIFI-CH, consideradas como teste referência, com as diluições da RIFI-BM (antígeno heterólogo. RESULTADOS: A diluição 1:20 do teste RIFI-CH apresentou o melhor coeficiente de contingência (0,755 e a maior força de associação entre as duas variáveis estudadas (qui-quadrado=124,3, sendo considerada a diluição-referência do teste nas comparações com as diferentes diluições do teste RIFI-BM. Os melhores resultados do RIFI-BM foram obtidos na diluição 1:40, com melhor coeficiente de contingência (0,680 e maior força de associação (qui-quadrado=80,8. Com a mudança do ponto de corte sugerido nesta análise para a diluição 1:40 da RIFI-BM, o valor do parâmetro especificidade aumentou de 57,5% para 97,7%, embora a diluição 1:80 tivesse apresentado a melhor estimativa para sensibilidade (80,2% com o novo ponto de corte. CONCLUSÕES: A análise TG-ROC pode fornecer importantes informações sobre os testes de diagnósticos, além de apresentar sugestões sobre pontos de cortes que podem melhorar as estimativas de sensibilidade e especificidade do teste, e avaliá-los a luz do melhor custo

  16. Diagnostic yield of ink-jet prints from digital radiographs for the assessment of approximal carious lesions: ROC-analysis

    International Nuclear Information System (INIS)

    Schulze, Ralf K.W.; Grimm, Stefanie; Schulze, Dirk; Voss, Kai; Keller, Hans-Peter; Wedel, Matthias

    2011-01-01

    Aims: To investigate the diagnostic quality of different quality, individually calibrated ink-jet printers for the very challenging dental radiographic task of approximal carious lesion detection. Materials and methods: A test-pattern evaluating resolution, contrast and homogeneity of the ink-jet prints was developed. 50 standardized dental radiographs each showing two neighbouring teeth in natural contact were printed on glossy paper with calibrated, randomly selected ink-jet printers (Canon S520 and iP4500, Epson Stylus Photo R2400). Printing size equalled the viewing size on a 17'' cathode-ray-tube monitor daily quality-tested according to German regulations. The true caries status was determined from serial sectioning and microscopic evaluation. 16 experienced observers evaluated the radiographs on a five-point confidence scale on all prints plus the viewing monitor with respect to the visibility of a carious lesion. A non-parametric Receiver-Operating Characteristics (ROC-) analysis was performed explicitly designed for the evaluation of readings stemming from identical samples but different modality. Significant differences are expressed by a critical ratio z exceeding ±2. Diagnostic accuracy was determined by the area (Az) underneath the ROC-curves. Results: Average Az-values ranged between 0.62 (S520 and R2400) and 0.64 (monitor, iP4500), with no significant difference between modalities (P = 0.172). Neither significant (range mean z: -0.40 (S520) and -0.11 (iP4500)) nor clinically relevant differences were found between printers and viewing monitor. Conclusions: Our results for a challenging task in dental radiography indicate that calibrated, off-the-shelf ink-jet printers are able to reproduce (dental) radiographs at quality levels sufficient for radiographic diagnosis in a typical dental working environment.

  17. Construction of joint confidence regions for the optimal true class fractions of Receiver Operating Characteristic (ROC) surfaces and manifolds.

    Science.gov (United States)

    Bantis, Leonidas E; Nakas, Christos T; Reiser, Benjamin; Myall, Daniel; Dalrymple-Alford, John C

    2017-06-01

    The three-class approach is used for progressive disorders when clinicians and researchers want to diagnose or classify subjects as members of one of three ordered categories based on a continuous diagnostic marker. The decision thresholds or optimal cut-off points required for this classification are often chosen to maximize the generalized Youden index (Nakas et al., Stat Med 2013; 32: 995-1003). The effectiveness of these chosen cut-off points can be evaluated by estimating their corresponding true class fractions and their associated confidence regions. Recently, in the two-class case, parametric and non-parametric methods were investigated for the construction of confidence regions for the pair of the Youden-index-based optimal sensitivity and specificity fractions that can take into account the correlation introduced between sensitivity and specificity when the optimal cut-off point is estimated from the data (Bantis et al., Biomet 2014; 70: 212-223). A parametric approach based on the Box-Cox transformation to normality often works well while for markers having more complex distributions a non-parametric procedure using logspline density estimation can be used instead. The true class fractions that correspond to the optimal cut-off points estimated by the generalized Youden index are correlated similarly to the two-class case. In this article, we generalize these methods to the three- and to the general k-class case which involves the classification of subjects into three or more ordered categories, where ROC surface or ROC manifold methodology, respectively, is typically employed for the evaluation of the discriminatory capacity of a diagnostic marker. We obtain three- and multi-dimensional joint confidence regions for the optimal true class fractions. We illustrate this with an application to the Trail Making Test Part A that has been used to characterize cognitive impairment in patients with Parkinson's disease.

  18. Diagnostic yield of ink-jet prints from digital radiographs for the assessment of approximal carious lesions: ROC-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Ralf K.W., E-mail: rschulze@mail.uni-mainz.de [Poliklinik fuer Zahnaerztliche Chirurgie, University Medical Center of the Johannes Gutenberg-University, Augustusplatz 2, D-55131 Mainz (Germany); Grimm, Stefanie, E-mail: StefanieGrimm@gmx.de [Poliklinik fuer Zahnaerztliche Chirurgie, University Medical Center of the Johannes Gutenberg-University, Augustusplatz 2, D-55131 Mainz (Germany); Schulze, Dirk, E-mail: dirk.schulze@uniklinik-freiburg.de [Klinik fuer Mund,- Kiefer- und Gesichtschirurgie, Sektion Roentgen, Universitaetsklinikum Freiburg, Hugstetterstr. 55, D-79106 Freiburg (Germany); Voss, Kai, E-mail: zahnarzt@drvoss.eu [Zahnaerztekammer Schleswig-Holstein, Vorstand fuer Praxisfuehrung, Westring 496, D- 24106 Kiel (Germany); Keller, Hans-Peter, E-mail: hans-peter.keller@din.de [NA Dental (NADENT) im DIN, Alexander-Wellendorff-Str. 2, D-75172 Pforzheim (Germany); Wedel, Matthias, E-mail: matthias.wedel@siemens.com [Siemens AG, Medical Solutions, Postfach 32 60, D-91050 Erlangen (Germany)

    2011-08-15

    Aims: To investigate the diagnostic quality of different quality, individually calibrated ink-jet printers for the very challenging dental radiographic task of approximal carious lesion detection. Materials and methods: A test-pattern evaluating resolution, contrast and homogeneity of the ink-jet prints was developed. 50 standardized dental radiographs each showing two neighbouring teeth in natural contact were printed on glossy paper with calibrated, randomly selected ink-jet printers (Canon S520 and iP4500, Epson Stylus Photo R2400). Printing size equalled the viewing size on a 17'' cathode-ray-tube monitor daily quality-tested according to German regulations. The true caries status was determined from serial sectioning and microscopic evaluation. 16 experienced observers evaluated the radiographs on a five-point confidence scale on all prints plus the viewing monitor with respect to the visibility of a carious lesion. A non-parametric Receiver-Operating Characteristics (ROC-) analysis was performed explicitly designed for the evaluation of readings stemming from identical samples but different modality. Significant differences are expressed by a critical ratio z exceeding {+-}2. Diagnostic accuracy was determined by the area (Az) underneath the ROC-curves. Results: Average Az-values ranged between 0.62 (S520 and R2400) and 0.64 (monitor, iP4500), with no significant difference between modalities (P = 0.172). Neither significant (range mean z: -0.40 (S520) and -0.11 (iP4500)) nor clinically relevant differences were found between printers and viewing monitor. Conclusions: Our results for a challenging task in dental radiography indicate that calibrated, off-the-shelf ink-jet printers are able to reproduce (dental) radiographs at quality levels sufficient for radiographic diagnosis in a typical dental working environment.

  19. Duck Valley Reservoirs Fish Stocking and Operation and Maintenance, 2005-2006 Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Sellman, Jake; Dykstra, Tim [Shoshone-Paiute Tribes

    2009-05-11

    The Duck Valley Reservoirs Fish Stocking and Operations and Maintenance (DV Fisheries) project is an ongoing resident fish program designed to enhance both subsistence fishing, educational opportunities for Tribal members of the Shoshone-Paiute Tribes, and recreational fishing facilities for non-Tribal members. In addition to stocking rainbow trout (Oncorhynchus mykiss) in Mountain View, Lake Billy Shaw, and Sheep Creek Reservoirs, the program also intends to afford and maintain healthy aquatic conditions for fish growth and survival, to provide superior facilities with wilderness qualities to attract non-Tribal angler use, and to offer clear, consistent communication with the Tribal community about this project as well as outreach and education within the region and the local community. Tasks for this performance period are divided into operations and maintenance plus monitoring and evaluation. Operation and maintenance of the three reservoirs include fences, roads, dams and all reservoir structures, feeder canals, water troughs and stock ponds, educational signs, vehicles and equipment, and outhouses. Monitoring and evaluation activities included creel, gillnet, wildlife, and bird surveys, water quality and reservoir structures monitoring, native vegetation planting, photo point documentation, control of encroaching exotic vegetation, and community outreach and education. The three reservoirs are monitored in terms of water quality and fishery success. Sheep Creek Reservoir was the least productive as a result of high turbidity levels and constraining water quality parameters. Lake Billy Shaw trout were in poorer condition than in previous years potentially as a result of water quality or other factors. Mountain View Reservoir trout exhibit the best health of the three reservoirs and was the only reservoir to receive constant flows of water.

  20. EXPLOITATION AND OPTIMIZATION OF RESERVOIR PERFORMANCE IN HUNTON FORMATION, OKLAHOMA

    Energy Technology Data Exchange (ETDEWEB)

    Mohan Kelkar

    2004-10-01

    West Carney field--one of the newest fields discovered in Oklahoma--exhibits many unique production characteristics. These characteristics include: (1) decreasing water-oil ratio; (2) decreasing gas-oil ratio followed by an increase; (3) poor prediction capability of the reserves based on the log data; and (4) low geological connectivity but high hydrodynamic connectivity. The purpose of this investigation is to understand the principal mechanisms affecting the production, and propose methods by which we can extend the phenomenon to other fields with similar characteristics. In our experimental investigation section, we present the data on surfactant injection in near well bore region. We demonstrate that by injecting the surfactant, the relative permeability of water could be decreased, and that of gas could be increased. This should result in improved gas recovery from the reservoir. Our geological analysis of the reservoir develops the detailed stratigraphic description of the reservoir. Two new stratigraphic units, previously unrecognized, are identified. Additional lithofacies are recognized in new core descriptions. Our engineering analysis has determined that well density is an important parameter in optimally producing Hunton reservoirs. It appears that 160 acre is an optimal spacing. The reservoir pressure appears to decline over time; however, recovery per well is only weakly influenced by the pressure. This indicates that additional opportunity to drill wells exists in relatively depleted fields. A simple material balance technique is developed to validate the recovery of gas, oil and water. This technique can be used to further extrapolate recoveries from other fields with similar field characteristics.

  1. Evaluation of Gaussian approximations for data assimilation in reservoir models

    KAUST Repository

    Iglesias, Marco A.

    2013-07-14

    implementation of the MCMC method provides the gold standard against which the aforementioned Gaussian approximations are assessed. We present numerical synthetic experiments where we quantify the capability of each of the ad hoc Gaussian approximation in reproducing the mean and the variance of the posterior distribution (characterized via MCMC) associated to a data assimilation problem. Both single-phase and two-phase (oil-water) reservoir models are considered so that fundamental differences in the resulting forward operators are highlighted. The main objective of our controlled experiments was to exhibit the substantial discrepancies of the approximation properties of standard ad hoc Gaussian approximations. Numerical investigations of the type we present here will lead to the greater understanding of the cost-efficient, but ad hoc, Bayesian techniques used for data assimilation in petroleum reservoirs and hence ultimately to improved techniques with more accurate uncertainty quantification. © 2013 Springer Science+Business Media Dordrecht.

  2. SAG/ROC-SCFβ-TrCP E3 Ubiquitin Ligase Promotes Pro-Caspase-3 Degradation as a Mechanism of Apoptosis Protection

    Directory of Open Access Journals (Sweden)

    Mingjia Tan

    2006-12-01

    Full Text Available Skp1-cullin-F-box protein (SCF is a multicomponent E3 ubiquitin (Ub ligase that ubiquitinates a number of important biologic molecules such as p27, β-catenin, and lκB for proteasomal degradation, thus regulating cell proliferation and survival. One SCF component, SAG/ROC2/Rbx2/Hrt2, a RING finger protein, was first identified as a redox-inducible protein, which, when overexpressed, inhibited apoptosis both in vitro and in vivo. We report here that sensitive to apoptosis gene (SAG, as well as its family member ROC1/Rbxi, bound to the proinactive form of caspase-3 (pro-caspase-3. Binding was likely mediated through F-box protein, β-transducin repeat-containing protein (β-TrCP, which binds to the first 38 amino acids of pro-caspase-3. Importantly, β-TrCP1 expression significantly shortened the protein half-life of pro-caspase-3, whereas expression of a dominant-negative β-TrCP1 mutant with the F-box domain deleted extended it. An in vitro ubiquitination assay showed that SAG/ROC-SCF -Trcp promoted ubiquitination of pro-caspase-3. Furthermore, endogenous levels of pro-caspase-3 were decreased by overexpression of SAG/ROC-SCFβ-TrCP E3 Ub ligases, but increased on siRNA silencing of SAG, regulator of cullin-1 (ROC1, or β-TrCPs, leading to increased apoptosis by etoposide and TNF-related apoptosis-inducing ligand through increased activation of caspase-3. Thus, pro-caspase-3 appears to be a substrate of SAG/ROC-SCFβ-TrCP E3 Ub ligase, which protects cells from apoptosis through increased apoptosis threshold by reducing the basal level of pro-caspase-3.

  3. Global Carbon Reservoir Oxidative Ratios

    Science.gov (United States)

    Masiello, C. A.; Gallagher, M. E.; Hockaday, W. C.

    2010-12-01

    Photosynthesis and respiration move carbon and oxygen between the atmosphere and the biosphere at a ratio that is characteristic of the biogeochemical processes involved. This ratio is called the oxidative ratio (OR) of photosynthesis and respiration, and is defined as the ratio of moles of O2 per moles of CO2. This O2/CO2 ratio is a characteristic of biosphere-atmosphere gas fluxes, much like the 13C signature of CO2 transferred between the biosphere and the atmosphere has a characteristic signature. OR values vary on a scale of 0 (CO2) to 2 (CH4), with most ecosystem values clustered between 0.9 and 1.2. Just as 13C can be measured for both carbon fluxes and carbon pools, OR can also be measured for fluxes and pools and can provide information about the processes involved in carbon and oxygen cycling. OR values also provide information about reservoir organic geochemistry because pool OR values are proportional to the oxidation state of carbon (Cox) in the reservoir. OR may prove to be a particularly valuable biogeochemical tracer because of its ability to couple information about ecosystem gas fluxes with ecosystem organic geochemistry. We have developed 3 methods to measure the OR of ecosystem carbon reservoirs and intercalibrated them to assure that they yield accurate, intercomparable data. Using these tools we have built a large enough database of biomass and soil OR values that it is now possible to consider the implications of global patterns in ecosystem OR values. Here we present a map of the natural range in ecosystem OR values and begin to consider its implications. One striking pattern is an apparent offset between soil and biospheric OR values: soil OR values are frequently higher than that of their source biomass. We discuss this trend in the context of soil organic geochemistry and gas fluxes.

  4. Are Geotehrmal Reservoirs Stressed Out?

    Science.gov (United States)

    Davatzes, N. C.; Laboso, R. C.; Layland-Bachmann, C. E.; Feigl, K. L.; Foxall, W.; Tabrez, A. R.; Mellors, R. J.; Templeton, D. C.; Akerley, J.

    2017-12-01

    Crustal permeability can be strongly influenced by developing connected networks of open fractures. However, the detailed evolution of a fracture network, its extent, and the persistence of fracture porosity are difficult to analyze. Even in fault-hosted geothermal systems, where heat is brought to the surface from depth along a fault, hydrothermal flow is heterogeneously distributed. This is presumably due to variations in fracture density, connectivity, and attitude, as well as variations in fracture permeability caused by sealing of fractures by precipitated cements or compaction. At the Brady Geothermal field in Nevada, we test the relationship between the modeled local stress state perturbed by dislocations representing fault slip or volume changes in the geothermal reservoir inferred from surface deformation measured by InSAR and the location of successful geothermal wells, hydrothermal activity, and seismicity. We postulate that permeability is favored in volumes that experience positive Coulomb stress changes and reduced compression, which together promote high densities of dilatant fractures. Conversely, permeability can be inhibited in locations where Coulomb stress is reduced, compression promotes compaction, or where the faults are poorly oriented in the stress field and consequently slip infrequently. Over geologic time scales spanning the development of the fault system, these local stress states are strongly influenced by the geometry of the fault network relative to the remote stress driving slip. At shorter time scales, changes in fluid pressure within the fracture network constituting the reservoir cause elastic dilations and contractions. We integrate: (1) direct observations of stress state and fractures in boreholes and the mapped geometry of the fault network; (2) evidence of permeability from surface hydrothermal features, production/injection wells and surface deformations related to pumping history; and (3) seismicity to test the

  5. A reservoir trap for antiprotons

    CERN Document Server

    Smorra, Christian; Franke, Kurt; Nagahama, Hiroki; Schneider, Georg; Higuchi, Takashi; Van Gorp, Simon; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Yamazaki, Yasunori; Ulmer, Stefan

    2015-01-01

    We have developed techniques to extract arbitrary fractions of antiprotons from an accumulated reservoir, and to inject them into a Penning-trap system for high-precision measurements. In our trap-system antiproton storage times > 1.08 years are estimated. The device is fail-safe against power-cuts of up to 10 hours. This makes our planned comparisons of the fundamental properties of protons and antiprotons independent from accelerator cycles, and will enable us to perform experiments during long accelerator shutdown periods when background magnetic noise is low. The demonstrated scheme has the potential to be applied in many other precision Penning trap experiments dealing with exotic particles.

  6. Effect of reservoir heterogeneity on air injection performance in a light oil reservoir

    Directory of Open Access Journals (Sweden)

    Hu Jia

    2018-03-01

    Full Text Available Air injection is a good option to development light oil reservoir. As well-known that, reservoir heterogeneity has great effect for various EOR processes. This also applies to air injection. However, oil recovery mechanisms and physical processes for air injection in heterogeneous reservoir with dip angle are still not well understood. The reported setting of reservoir heterogeneous for physical model or simulation model of air injection only simply uses different-layer permeability of porous media. In practice, reservoir heterogeneity follows the principle of geostatistics. How much of contrast in permeability actually challenges the air injection in light oil reservoir? This should be investigated by using layered porous medial settings of the classical Dykstra-Parsons style. Unfortunately, there has been no work addressing this issue for air injection in light oil reservoir. In this paper, Reservoir heterogeneity is quantified based on the use of different reservoir permeability distribution according to classical Dykstra-Parsons coefficients method. The aim of this work is to investigate the effect of reservoir heterogeneity on physical process and production performance of air injection in light oil reservoir through numerical reservoir simulation approach. The basic model is calibrated based on previous study. Total eleven pseudo compounders are included in this model and ten complexity of reactions are proposed to achieve the reaction scheme. Results show that oil recovery factor is decreased with the increasing of reservoir heterogeneity both for air and N2 injection from updip location, which is against the working behavior of air injection from updip location. Reservoir heterogeneity sometimes can act as positive effect to improve sweep efficiency as well as enhance production performance for air injection. High O2 content air injection can benefit oil recovery factor, also lead to early O2 breakthrough in heterogeneous reservoir. Well

  7. Data Compression of Hydrocarbon Reservoir Simulation Grids

    KAUST Repository

    Chavez, Gustavo Ivan

    2015-05-28

    A dense volumetric grid coming from an oil/gas reservoir simulation output is translated into a compact representation that supports desired features such as interactive visualization, geometric continuity, color mapping and quad representation. A set of four control curves per layer results from processing the grid data, and a complete set of these 3-dimensional surfaces represents the complete volume data and can map reservoir properties of interest to analysts. The processing results yield a representation of reservoir simulation results which has reduced data storage requirements and permits quick performance interaction between reservoir analysts and the simulation data. The degree of reservoir grid compression can be selected according to the quality required, by adjusting for different thresholds, such as approximation error and level of detail. The processions results are of potential benefit in applications such as interactive rendering, data compression, and in-situ visualization of large-scale oil/gas reservoir simulations.

  8. Lesion type and reader experience affect the diagnostic accuracy of breast MRI: A multiple reader ROC study

    Energy Technology Data Exchange (ETDEWEB)

    Baltzer, Pascal A.T., E-mail: patbaltzer@gmail.com [Department of Biomedical Imaging and Imge-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Kaiser, Werner Alois [Department of Diagnostic and Interventional Radiology, University Hospital Jena, Erlanger Allee 101, 07740 Jena (Germany); Dietzel, Matthias, E-mail: dietzelmatthias2@hotmail.com [Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen (Germany)

    2015-01-15

    Highlights: • The main findings of our study are, that reader experience and lesion type (i.e., mass versus non-mass enhancement) are independent predictors of the diagnostic accuracy of breast MRI. • Specifically, benign and malignant non-mass lesions cannot be differentiated with sufficient accuracy, especially if readers are not experienced. • We conclude that future research in breast MRI should focus on non-mass lesions, as these are the problem makers in modern breast MRI. - Abstract: Purpose: To evaluate the influence of lesion type (mass versus non-mass) and reader experience on the diagnostic performance of breast MRI (BMRI) in a non-screening setting. Materials and methods: Consecutive patients (mean age, 55 ± 12 years) with breast lesions that were verified by biopsy or surgery, and who had had BMRI as part of their diagnostic workup, were eligible for this retrospective single-center study. Cancers diagnosed by biopsy before BMRI were excluded to eliminate biological and interpretation bias due to biopsy or chemotherapy effects (n = 103). Six blinded readers (experience level, high (HE, n = 2); intermediate (IE, n = 2); and low (LE, n = 2)) evaluated all examinations and assigned independent MRI BI-RADS ratings. Lesion type (mass, non-mass, focal) was noted. Receiver operating characteristics (ROC) and logistic regression analysis was performed to compare diagnostic accuracies. Results: There were 259 histologically verified lesions (123 malignant, 136 benign) investigated. There were 169 mass (103 malignant, 66 benign) and 48 non-mass lesions (19 malignant, 29 benign). Another 42 lesions that met the inclusion criteria were biopsied due to conventional findings (i.e., microcalcifications, architectural distortions), but did not enhance on MRI (41 benign, one DCIS). ROC analysis revealed a total area under the curve (AUC) between 0.834 (LE) and 0.935 (HI). Logistic regression identified a significant effect of non-mass lesions (P < 0.0001) and

  9. Adenoid Reservoir for Pathogenic Biofilm Bacteria▿

    Science.gov (United States)

    Nistico, L.; Kreft, R.; Gieseke, A.; Coticchia, J. M.; Burrows, A.; Khampang, P.; Liu, Y.; Kerschner, J. E.; Post, J. C.; Lonergan, S.; Sampath, R.; Hu, F. Z.; Ehrlich, G. D.; Stoodley, P.; Hall-Stoodley, L.

    2011-01-01

    Biofilms of pathogenic bacteria are present on the middle ear mucosa of children with chronic otitis media (COM) and may contribute to the persistence of pathogens and the recalcitrance of COM to antibiotic treatment. Controlled studies indicate that adenoidectomy is effective in the treatment of COM, suggesting that the adenoids may act as a reservoir for COM pathogens. To investigate the bacterial community in the adenoid, samples were obtained from 35 children undergoing adenoidectomy for chronic OM or obstructive sleep apnea. We used a novel, culture-independent molecular diagnostic methodology, followed by confocal microscopy, to investigate the in situ distribution and organization of pathogens in the adenoids to determine whether pathogenic bacteria exhibited criteria characteristic of biofilms. The Ibis T5000 Universal Biosensor System was used to interrogate the extent of the microbial diversity within adenoid biopsy specimens. Using a suite of 16 broad-range bacterial primers, we demonstrated that adenoids from both diagnostic groups were colonized with polymicrobial biofilms. Haemophilus influenzae was present in more adenoids from the COM group (P = 0.005), but there was no significant difference between the two patient groups for Streptococcus pneumoniae or Staphylococcus aureus. Fluorescence in situ hybridization, lectin binding, and the use of antibodies specific for host epithelial cells demonstrated that pathogens were aggregated, surrounded by a carbohydrate matrix, and localized on and within the epithelial cell surface, which is consistent with criteria for bacterial biofilms. PMID:21307211

  10. Artefacts and the performance of an exhibition

    DEFF Research Database (Denmark)

    Svabo, Connie

    2008-01-01

    The article explores the role of mediating artefacts in children's encounters with a museum of natural history. Using actor network theory it explores how a specific artefact shapes the way users relate to exhibited objects and how the artefact guides users' movements in the exhibition....... The mediated performance of an exhibition is explored through an empirical case....

  11. Assessment of disturbance at three spatial scales in two large tropical reservoirs

    Directory of Open Access Journals (Sweden)

    Letícia de Morais

    2016-12-01

    Full Text Available Large reservoirs are an increasingly common feature across tropical landscapes because of their importance for water supply, flood control and hydropower, but their ecological conditions are infrequently evaluated. Our objective was to assess the range of disturbances for two large tropical reservoirs and their influences on benthic macroinvertebrates. We tested three hypotheses: i a wide variation in the level of environmental disturbance can be observed among sites in the reservoirs; ii the two reservoirs would exhibit a different degree of disturbance level; and iii the magnitude of disturbance would influence the structure and composition of benthic assemblages. For each reservoir, we assessed land use (macroscale, physical habitat structure (mesoscale, and water quality (microscale. We sampled 40 sites in the littoral zones of both Três Marias and São Simão Reservoirs (Minas Gerais, Brazil. At the macroscale, we measured cover percentages of land use categories in buffer areas at each site, where each buffer was a circular arc of 250 m. At the mesoscale, we assessed the presence of human disturbances in the riparian and drawdown zones at the local (site scale. At the microscale, we assessed water quality at each macroinvertebrate sampling station using the Micro Disturbance Index (MDI. To evaluate anthropogenic disturbance of each site, we calculated an integrated disturbance index (IDI from a buffer disturbance index (BDI and a local disturbance index (LDI. For each site, we calculated richness and abundance of benthic macroinvertebrates, Chironomidae genera richness, abundance and percent Chironomidae individuals, abundance and percent EPT individuals, richness and percent EPT taxa, abundance and percent resistant individuals, and abundance and percent non-native individuals. We also evaluated the influence of disturbance on benthic macroinvertebrate assemblages at the entire-reservoir scale. The BDI, LDI and IDI had significantly

  12. Muon Tomography of Deep Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Bonneville, Alain H.; Kouzes, Richard T.

    2016-12-31

    Imaging subsurface geological formations, oil and gas reservoirs, mineral deposits, cavities or magma chambers under active volcanoes has been for many years a major quest of geophysicists and geologists. Since these objects cannot be observed directly, different indirect geophysical methods have been developed. They are all based on variations of certain physical properties of the subsurface that can be detected from the ground surface or from boreholes. Electrical resistivity, seismic wave’s velocities and density are certainly the most used properties. If we look at density, indirect estimates of density distributions are performed currently by seismic reflection methods - since the velocity of seismic waves depend also on density - but they are expensive and discontinuous in time. Direct estimates of density are performed using gravimetric data looking at variations of the gravity field induced by the density variations at depth but this is not sufficiently accurate. A new imaging technique using cosmic-ray muon detectors has emerged during the last decade and muon tomography - or muography - promises to provide, for the first time, a complete and precise image of the density distribution in the subsurface. Further, this novel approach has the potential to become a direct, real-time, and low-cost method for monitoring fluid displacement in subsurface reservoirs.

  13. Development of gas and gas condensate reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-01

    In the study of gas reservoir development, the first year topics are restricted on reservoir characterization. There are two types of reservoir characterization. One is the reservoir formation characterization and the other is the reservoir fluid characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. The results of conditional simulation has higher confidence level than the unconditional simulation because conditional simulation considers the sample location as well as distance correlation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. From the liquid volume fraction with pressure drop, the phase behavior of reservoir fluid can be estimated. The calculation results of fluid recombination, constant composition expansion, and constant volume depletion are matched very well with the experimental data. In swelling test of the reservoir fluid with lean gas, the accuracy of dew point pressure forecast depends on the component characterization. (author). 28 figs., 10 tabs.

  14. Stretch due to Penile Prosthesis Reservoir Migration

    Directory of Open Access Journals (Sweden)

    E. Baten

    2016-03-01

    Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.

  15. Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

    KAUST Repository

    Katterbauer, Klemens; Hoteit, Ibrahim

    2014-01-01

    process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase

  16. Multi-data reservoir history matching for enhanced reservoir forecasting and uncertainty quantification

    KAUST Repository

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2015-01-01

    Reservoir simulations and history matching are critical for fine-tuning reservoir production strategies, improving understanding of the subsurface formation, and forecasting remaining reserves. Production data have long been incorporated

  17. Multiple long-term trends and trend reversals dominate environmental conditions in a man-made freshwater reservoir.

    Science.gov (United States)

    Znachor, Petr; Nedoma, Jiří; Hejzlar, Josef; Seďa, Jaromír; Kopáček, Jiří; Boukal, David; Mrkvička, Tomáš

    2018-05-15

    Man-made reservoirs are common across the world and provide a wide range of ecological services. Environmental conditions in riverine reservoirs are affected by the changing climate, catchment-wide processes and manipulations with the water level, and water abstraction from the reservoir. Long-term trends of environmental conditions in reservoirs thus reflect a wider range of drivers in comparison to lakes, which makes the understanding of reservoir dynamics more challenging. We analysed a 32-year time series of 36 environmental variables characterising weather, land use in the catchment, reservoir hydrochemistry, hydrology and light availability in the small, canyon-shaped Římov Reservoir in the Czech Republic to detect underlying trends, trend reversals and regime shifts. To do so, we fitted linear and piecewise linear regression and a regime shift model to the time series of mean annual values of each variable and to principal components produced by Principal Component Analysis. Models were weighted and ranked using Akaike information criterion and the model selection approach. Most environmental variables exhibited temporal changes that included time-varying trends and trend reversals. For instance, dissolved organic carbon showed a linear increasing trend while nitrate concentration or conductivity exemplified trend reversal. All trend reversals and cessations of temporal trends in reservoir hydrochemistry (except total phosphorus concentrations) occurred in the late 1980s and during 1990s as a consequence of dramatic socioeconomic changes. After a series of heavy rains in the late 1990s, an administrative decision to increase the flood-retention volume of the reservoir resulted in a significant regime shift in reservoir hydraulic conditions in 1999. Our analyses also highlight the utility of the model selection framework, based on relatively simple extensions of linear regression, to describe temporal trends in reservoir characteristics. This approach can

  18. Habitat suitability mapping of Anopheles darlingi in the surroundings of the Manso hydropower plant reservoir, Mato Grosso, Central Brazil

    Directory of Open Access Journals (Sweden)

    Miyazaki Rosina D

    2007-03-01

    Full Text Available Abstract Background Hydropower plants provide more than 78 % of Brazil's electricity generation, but the country's reservoirs are potential new habitats for main vectors of malaria. In a case study in the surroundings of the Manso hydropower plant in Mato Grosso state, Central Brazil, habitat suitability of Anopheles darlingi was studied. Habitat profile was characterized by collecting environmental data. Remote sensing and GIS techniques were applied to extract additional spatial layers of land use, distance maps, and relief characteristics for spatial model building. Results Logistic regression analysis and ROC curves indicate significant relationships between the environment and presence of An. darlingi. Probabilities of presence strongly vary as a function of land cover and distance from the lake shoreline. Vector presence was associated with spatial proximity to reservoir and semi-deciduous forests followed by Cerrado woodland. Vector absence was associated with open vegetation formations such as grasslands and agricultural areas. We suppose that non-significant differences of vector incidences between rainy and dry seasons are associated with the availability of anthropogenic breeding habitat of the reservoir throughout the year. Conclusion Satellite image classification and multitemporal shoreline simulations through DEM-based GIS-analyses consist in a valuable tool for spatial modeling of A. darlingi habitats in the studied hydropower reservoir area. Vector presence is significantly increased in forested areas near reservoirs in bays protected from wind and wave action. Construction of new reservoirs under the tropical, sub-humid climatic conditions should therefore be accompanied by entomologic studies to predict the risk of malaria epidemics.

  19. Increasing Waterflooding Reservoirs in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, Roy; Clarke, Don; Walker, Scott

    1999-11-09

    The objectives of this quarterly report was to summarize the work conducted under each task during the reporting period April - June 1998 and to report all technical data and findings as specified in the ''Federal Assistance Reporting Checklist''. The main objective of this project is the transfer of technologies, methodologies, and findings developed and applied in this project to other operators of Slope and Basin Clastic Reservoirs. This project will study methods to identify sands with high remaining oil saturation and to recomplete existing wells using advanced completion technology.

  20. Affordances and distributed cognition in museum exhibitions

    DEFF Research Database (Denmark)

    Achiam, Marianne; May, Michael; Marandino, Martha

    2014-01-01

    consistent framework. Here, we invoke the notions of affordance and distributed cognition to explain in a coherent way how visitors interact with exhibits and exhibit spaces and make meaning from those interactions, and we exemplify our points using observations of twelve visitors to exhibits at a natural...... history museum. We show how differences in exhibit characteristics give rise to differences in the interpretive strategies used by visitors in their meaning-making process, and conclude by discussing how the notions of affordance and distributed cognition can be used in an exhibit design perspective....

  1. Evaluation of computer tomograms using a black-and-white monitor and a colour monitor: A ROC comparison

    International Nuclear Information System (INIS)

    Rockstroh, G.; Rotte, K.H.; Kriedemann, E.

    1987-01-01

    Different views about the value of a colour monitor for the evaluation of computer tomograms have prompted us to carry out this ROC (Receiver Operation Characteristic) examination. The latter was based on patient computer tomograms in which lesions of the liver were simulated by image manipulation. 5 radiologists analysed the image material (a) on a black-and-white monitor, (b) on a colour monitor, and (c) simultaneously on a black-and-white and a colour monitor. The study shows that the use of a colour monitor gives no essentially different result than evaluation with a black-and-white monitor. The slightly better result of 2% more true positive findings with simultaneous representation of black-and-white and colour image relative to the sole use of black-and-white display is within error limits. The colour representation gives no advantages for the evaluation of usual computer tomograms because the window technique enables a contrasty representation in black-and-white too. (orig.) [de

  2. [Programme review of somatropin deficit in pediatrics at the Hospital Universitario Virgen del Rocío].

    Science.gov (United States)

    Lavaredas, A; de la Puerta, R; Álvarez del Vayo, C

    2013-01-01

    To develop a program review of somatropin deficit, applied in pediatrics at the Hospital Universitario Virgen del Rocío, using two groups of patients: the ones diagnosed with deficiency of this hormone, and those born small for gestational age, with the intention of evaluating its effectiveness in the first year of treatment. Attaining a retrospective study of the cohort of patients treated with growth hormone under the above diagnoses, with cross-sectional and observational methodology, to which we applied a statistical analysis with the Statistical Package for Social Sciences®. After the beginning of the treatment, the growth rate had increased and the bone age approximated to the chronologic age. In the two treated groups in the first year of treatment were the female patients aged between 0 to 12 years with a deficit of growth hormone who responded better to therapy. We observed that the treatment instituted appeared highly effective in both groups of patients, allowing a favorable increase in height. Copyright © 2013 SEFH. Published by AULA MEDICA. All rights reserved.

  3. Comparison of 18F-FDG PET to CT scan in the detection of recurrent colorectal carcinoma - an ROC analysis

    International Nuclear Information System (INIS)

    Scott, A.M.; Akhurst, T.; Berlangieri, S.U.; Fitt, G.; Schelleman, T.; Jones, R.; Hannah, A.; Tochon-Danguy, H.

    2000-01-01

    Full text: This study examined 43 scans performed in 40 patients from a group of 93 prospectively enrolled in a trial examining the utility of 18 F-FDG PET in patients with potentially resectable recurrent colorectal cancer. All patients had PET and CT scans prior to surgery, where a total of 84 anatomical regions were biopsied, and 364 regions examined by the surgeons. All PET and CT scans were viewed blinded to clinical and imaging data. The scans were interpreted according to a five-point confidence scale to enable an ROC analysis to be performed. An assessment of the impact of PET over CT in patients was also made. Of the 43 cases PET and CT were concordant in 24 (56%). There were 16 cases where PET added additional diagnostic information to the benefit of the patient (37%), and three (7%) where PET alone would have lead to a potentially negative outcome. The majority of cases where PET performed better were in cases with extrahepatic disease. CT was more sensitive in the detection of pulmonary nodules, although the specificity of CT was less than PET. In conclusion, 18 F-FDG PET performed significantly better than CT both in terms of a regional analysis as well as a patient by patient basis. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  4. Estimation of Bank Erosion Due To Reservoir Operation in Cascade (Case Study: Citarum Cascade Reservoir

    Directory of Open Access Journals (Sweden)

    Sri Legowo

    2009-11-01

    Full Text Available Sedimentation is such a crucial issue to be noted once the accumulated sediment begins to fill the reservoir dead storage, this will then influence the long-term reservoir operation. The sediment accumulated requires a serious attention for it may influence the storage capacity and other reservoir management of activities. The continuous inflow of sediment to the reservoir will decrease the capacity of reservoir storage, the reservoir value in use, and the useful age of reservoir. Because of that, the rate of the sediment needs to be delayed as possible. In this research, the delay of the sediment rate is considered based on the rate of flow of landslide of the reservoir slope. The rate of flow of the sliding slope can be minimized by way of each reservoir autonomous efforts. This effort can be performed through; the regulation of fluctuating rate of reservoir surface current that does not cause suddenly drawdown and upraising as well. The research model is compiled using the searching technique of Non Linear Programming (NLP.The rate of bank erosion for the reservoir variates from 0.0009 to 0.0048 MCM/year, which is no sigrificant value to threaten the life time of reservoir.Mean while the rate of watershed sediment has a significant value, i.e: 3,02 MCM/year for Saguling that causes to fullfill the storage capacity in 40 next years (from years 2008.

  5. Radiocesium dynamics in herons inhabiting a contaminated reservoir system

    International Nuclear Information System (INIS)

    Dombey, A.H.; Paine, D.; McFarlane, R.W.

    1977-01-01

    The little blue heron (Florida caerulea) and the green heron (Butorides virescens) nest at a radionuclide-contaminated reservoir on the Savannah River Plant near Aiken, South Carolina. Green herons distributed their nests singly along the periphery of the reservoir but fed their nestlings exclusively upon amphibians collected from adjacent uncontaminated Carolina bays. Radiocesium burdens in green heron nestlings did not exceed 5 pCi/g wet wt. and 12 regurgitated food pellets averaged 0.2 pCi/g. Twelve pairs of little blue herons established a heronry upon a small island and fed their nestlings fish and amphibians foraged from within the differentially radionuclide-contaminated reservoir system. Nestlings within the same nest did not exhibit significant differences in body burdens, and the maximum radiocesium burden determined was 27.4 pCi/g wet wt. Substantial differences were found between nestlings from different nests however. The radiocesium level of 43 regurgitated food pellets had a high correlation with observed levels in the nestlings, and variation in food contamination is believed to be the major contributor in the observed variation in the nestlings. The variable contamination of primary prey species was correlated with the differentially contaminated foraging sites and indicates that adult little blue herons tended to spatially partition the available foraging areas. (author)

  6. Recognition Memory zROC Slopes for Items with Correct versus Incorrect Source Decisions Discriminate the Dual Process and Unequal Variance Signal Detection Models

    Science.gov (United States)

    Starns, Jeffrey J.; Rotello, Caren M.; Hautus, Michael J.

    2014-01-01

    We tested the dual process and unequal variance signal detection models by jointly modeling recognition and source confidence ratings. The 2 approaches make unique predictions for the slope of the recognition memory zROC function for items with correct versus incorrect source decisions. The standard bivariate Gaussian version of the unequal…

  7. Smart Waterflooding in Carbonate Reservoirs

    DEFF Research Database (Denmark)

    Zahid, Adeel

    brine solutions regarding phase behavior and viscosity measurements. This difference is attributed to the difference in composition of the different crude oils. More experiments are carried out in order to understand mechanisms of the crude oil viscosity reduction and emulsion formation. We observed...... with and without aging. The total oil recovery, recovery rate and interaction mechanisms of ions with rock were studied for different injected fluids under different temperatures and wettability conditions. Experimental results demonstrate that the oil recovery mechanism under high salinity seawater flooding...... phase could be the possible reasons for the observed increase in oil recovery with sulfate ions at high temperature in chalk reservoirs, besides the mechanism of the rock wettability alteration. * Crude oil/brine interaction study suggests that viscosity reduction for crude oil in contact with brine...

  8. Reservoirs talk to pressure recorders

    Energy Technology Data Exchange (ETDEWEB)

    Pamenter, C B

    1968-02-01

    Keeping pace with increased demand for efficiency in secondary recovery schemes is the widening use of downhole tools charged with supplying data before and during the operation of the projects. One of the most important of these is the pressure recorder. This highly sensitive instrument, housed in a tough, slim steel case and lowered by drill pipe or cable, accurately measures the pressure of its downhole environment. This information is instantly available at the surface whenever a pressure reading is required. Typical applications of surface recorders often contribute are: (1) production practices such as checking surface and subsurface equipment, and special lifting problems; (2) well conditions including regular productivity indices, data observations and for interference studies; (3) secondary recovery projects, in both producing and injection wells; and (4) reservoir conditions where oil-water contacts and damaged zones need close attention.

  9. Production Optimization of Oil Reservoirs

    DEFF Research Database (Denmark)

    Völcker, Carsten

    with emphasis on optimal control of water ooding with the use of smartwell technology. We have implemented immiscible ow of water and oil in isothermal reservoirs with isotropic heterogenous permeability elds. We use the method of lines for solution of the partial differential equation (PDE) system that governs...... the uid ow. We discretize the the two-phase ow model spatially using the nite volume method (FVM), and we use the two point ux approximation (TPFA) and the single-point upstream (SPU) scheme for computing the uxes. We propose a new formulation of the differential equation system that arise...... as a consequence of the spatial discretization of the two-phase ow model. Upon discretization in time, the proposed equation system ensures the mass conserving property of the two-phase ow model. For the solution of the spatially discretized two-phase ow model, we develop mass conserving explicit singly diagonally...

  10. Economics of Developing Hot Stratigraphic Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Greg Mines; Hillary Hanson; Rick Allis; Joseph Moore

    2014-09-01

    Stratigraphic geothermal reservoirs at 3 – 4 km depth in high heat-flow basins are capable of sustaining 100 MW-scale power plants at about 10 c/kWh. This paper examines the impacts on the levelized cost of electricity (LCOE) of reservoir depth and temperature, reservoir productivity, and drillhole/casing options. For a reservoir at 3 km depth with a moderate productivity index by hydrothermal reservoir standards (about 50 L/s/MPa, 5.6 gpm/psi), an LCOE of 10c/kWh requires the reservoir to be at about 200°C. This is the upper temperature limit for pumps. The calculations assume standard hydrothermal drilling costs, with the production interval completed with a 7 inch liner in an 8.5 inch hole. If a reservoir at 4 km depth has excellent permeability characteristics with a productivity index of 100 L/s/MPa (11.3 gpm/psi), then the LCOE is about 11 c/kWh assuming the temperature decline rate with development is not excessive (< 1%/y, with first thermal breakthrough delayed by about 10 years). Completing wells with modest horizontal legs (e.g. several hundred meters) may be important for improving well productivity because of the naturally high, sub-horizontal permeability in this type of reservoir. Reducing the injector/producer well ratio may also be cost-effective if the injectors are drilled as larger holes.

  11. Carbon emission from global hydroelectric reservoirs revisited.

    Science.gov (United States)

    Li, Siyue; Zhang, Quanfa

    2014-12-01

    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.

  12. Zooplankton of the Zaporiz’ke Reservoir

    Directory of Open Access Journals (Sweden)

    T. V. Mykolaichuk

    2006-01-01

    Full Text Available The paper is devoted to zooplankton species composition in the Zaporiz’ke Reservoir. The greatest species diversity was found in the macrophyte communities of the upper reservoir’s littoral, but the least zooplankton diversity – in the pelagic zone of the lower reservoir.

  13. Estimating Western U.S. Reservoir Sedimentation

    Science.gov (United States)

    Bensching, L.; Livneh, B.; Greimann, B. P.

    2017-12-01

    Reservoir sedimentation is a long-term problem for water management across the Western U.S. Observations of sedimentation are limited to reservoir surveys that are costly and infrequent, with many reservoirs having only two or fewer surveys. This work aims to apply a recently developed ensemble of sediment algorithms to estimate reservoir sedimentation over several western U.S. reservoirs. The sediment algorithms include empirical, conceptual, stochastic, and processes based approaches and are coupled with a hydrologic modeling framework. Preliminary results showed that the more complex and processed based algorithms performed better in predicting high sediment flux values and in a basin transferability experiment. However, more testing and validation is required to confirm sediment model skill. This work is carried out in partnership with the Bureau of Reclamation with the goal of evaluating the viability of reservoir sediment yield prediction across the western U.S. using a multi-algorithm approach. Simulations of streamflow and sediment fluxes are validated against observed discharges, as well as a Reservoir Sedimentation Information database that is being developed by the US Army Corps of Engineers. Specific goals of this research include (i) quantifying whether inter-algorithm differences consistently capture observational variability; (ii) identifying whether certain categories of models consistently produce the best results, (iii) assessing the expected sedimentation life-span of several western U.S. reservoirs through long-term simulations.

  14. Ichthyofauna of the reservoirs of Central Vietnam

    Directory of Open Access Journals (Sweden)

    I. A. Stolbunov

    2012-01-01

    Full Text Available Species composition, distribution and abundance of fish in the pelagic and littoral zone of four reservoirs of Central Vietnam (Suoi Chau, Kam Lam, Da Ban and Suoi Dau were studied first. According to the research data the fish community of the reservoirs is represented by 43 species of 19 fish families.

  15. An index of reservoir habitat impairment

    Science.gov (United States)

    Miranda, L.E.; Hunt, K.M.

    2011-01-01

    Fish habitat impairment resulting from natural and anthropogenic watershed and in-lake processes has in many cases reduced the ability of reservoirs to sustain native fish assemblages and fisheries quality. Rehabilitation of impaired reservoirs is hindered by the lack of a method suitable for scoring impairment status. To address this limitation, an index of reservoir habitat impairment (IRHI) was developed by merging 14 metrics descriptive of common impairment sources, with each metric scored from 0 (no impairment) to 5 (high impairment) by fisheries scientists with local knowledge. With a plausible range of 5 to 25, distribution of the IRHI scores ranged from 5 to 23 over 482 randomly selected reservoirs dispersed throughout the USA. The IRHI reflected five impairment factors including siltation, structural habitat, eutrophication, water regime, and aquatic plants. The factors were weakly related to key reservoir characteristics including reservoir area, depth, age, and usetype, suggesting that common reservoir descriptors are poor predictors of fish habitat impairment. The IRHI is rapid and inexpensive to calculate, provides an easily understood measure of the overall habitat impairment, allows comparison of reservoirs and therefore prioritization of restoration activities, and may be used to track restoration progress. The major limitation of the IRHI is its reliance on unstandardized professional judgment rather than standardized empirical measurements. ?? 2010 US Government.

  16. Monitoring programme of water reservoir Grliste

    International Nuclear Information System (INIS)

    Vuckovic, M; Milenkovic, P.; Lukic, D.

    2002-01-01

    The quality of surface waters is a very important problem incorporated in the environment protection, especially in water resources. The Timok border-land hasn't got sufficient underground and surface waters. This is certificated by the International Association for Water Resource. That was reason for building the water reservoir 'Grliste'. Drinking water from water reservoir 'Grliste' supplies Zajecar and the surroundings. (author)

  17. Geothermal reservoir insurance study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-10-09

    The principal goal of this study was to provide analysis of and recommendations on the need for and feasibility of a geothermal reservoir insurance program. Five major tasks are reported: perception of risk by major market sectors, status of private sector insurance programs, analysis of reservoir risks, alternative government roles, and recommendations.

  18. Investigating Design Research Landscapes through Exhibition

    DEFF Research Database (Denmark)

    Jönsson, Li; Hansen, Flemming Tvede; Mäkelä, Maarit

    2013-01-01

    What characterizes a design research exhibition compared to a traditional design and art exhibition? How do you show the very materialities of the design experiments as a means for communicating knowledge of research and of practice? How do you present, review and utilize such an exhibition......? With those questions in mind, the intention and challenge for the Nordes 2013 Design Research Exhibition was to expand on current notions of staging research enquires in design research conference contexts. Artefacts, installations, performances, and other materialities that relate to the theme...... of the conference - Experiments in Design Research – were displayed as tools to express and communicate different design research enquires. Through this paper we will describe the Nordes exhibition as a specific case that renders questions visible in relation to how to utilize a design research exhibition...

  19. Persistent Memory in Single Node Delay-Coupled Reservoir Computing.

    Directory of Open Access Journals (Sweden)

    André David Kovac

    Full Text Available Delays are ubiquitous in biological systems, ranging from genetic regulatory networks and synaptic conductances, to predator/pray population interactions. The evidence is mounting, not only to the presence of delays as physical constraints in signal propagation speed, but also to their functional role in providing dynamical diversity to the systems that comprise them. The latter observation in biological systems inspired the recent development of a computational architecture that harnesses this dynamical diversity, by delay-coupling a single nonlinear element to itself. This architecture is a particular realization of Reservoir Computing, where stimuli are injected into the system in time rather than in space as is the case with classical recurrent neural network realizations. This architecture also exhibits an internal memory which fades in time, an important prerequisite to the functioning of any reservoir computing device. However, fading memory is also a limitation to any computation that requires persistent storage. In order to overcome this limitation, the current work introduces an extended version to the single node Delay-Coupled Reservoir, that is based on trained linear feedback. We show by numerical simulations that adding task-specific linear feedback to the single node Delay-Coupled Reservoir extends the class of solvable tasks to those that require nonfading memory. We demonstrate, through several case studies, the ability of the extended system to carry out complex nonlinear computations that depend on past information, whereas the computational power of the system with fading memory alone quickly deteriorates. Our findings provide the theoretical basis for future physical realizations of a biologically-inspired ultrafast computing device with extended functionality.

  20. Persistent Memory in Single Node Delay-Coupled Reservoir Computing.

    Science.gov (United States)

    Kovac, André David; Koall, Maximilian; Pipa, Gordon; Toutounji, Hazem

    2016-01-01

    Delays are ubiquitous in biological systems, ranging from genetic regulatory networks and synaptic conductances, to predator/pray population interactions. The evidence is mounting, not only to the presence of delays as physical constraints in signal propagation speed, but also to their functional role in providing dynamical diversity to the systems that comprise them. The latter observation in biological systems inspired the recent development of a computational architecture that harnesses this dynamical diversity, by delay-coupling a single nonlinear element to itself. This architecture is a particular realization of Reservoir Computing, where stimuli are injected into the system in time rather than in space as is the case with classical recurrent neural network realizations. This architecture also exhibits an internal memory which fades in time, an important prerequisite to the functioning of any reservoir computing device. However, fading memory is also a limitation to any computation that requires persistent storage. In order to overcome this limitation, the current work introduces an extended version to the single node Delay-Coupled Reservoir, that is based on trained linear feedback. We show by numerical simulations that adding task-specific linear feedback to the single node Delay-Coupled Reservoir extends the class of solvable tasks to those that require nonfading memory. We demonstrate, through several case studies, the ability of the extended system to carry out complex nonlinear computations that depend on past information, whereas the computational power of the system with fading memory alone quickly deteriorates. Our findings provide the theoretical basis for future physical realizations of a biologically-inspired ultrafast computing device with extended functionality.

  1. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2013-01-01

    of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river. The freshwater reservoir effect has also implications......The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known...... as hard water, is the most common reason for the freshwater reservoir effect. It is therefore also called hardwater effect. Although it has been known for more than 60 years, it is still less well-recognized by archaeologists than the marine reservoir effect. The aim of this study is to examine the order...

  2. Reservoir model for the Alameda Central waterflood

    Energy Technology Data Exchange (ETDEWEB)

    Randall, T E

    1968-01-01

    The basic approach used in developing the model to characterize the Alameda Central Unit Waterflood assumes continuity of the reservoir mechanics with time. The past performance was analyzed to describe the reservoir and future performance was assumed to follow the established patterns. To develop a mathematical picture of the Alameda Central Unit reservoir, a two-dimensional single-phase steady-state model was used in conjunction with material balance calculations, real-time conversion methods and oil-water interface advance calculations. The model was developed to optimize water injection allocation, determine the configuration of the frontal advance and evaluate the success of the waterflood. The model also provides a basis for continuing review and revision of the basic concepts of reservoir operation. The results of the reservoir study have confirmed the apparent lack of permeability orientation in the pool and indicate that the waterflood is progressing better than originally anticipated.

  3. Superconductive microstrip exhibiting negative differential resistivity

    International Nuclear Information System (INIS)

    Huebener, R.P.; Gallus, D.E.

    1975-01-01

    A device capable of exhibiting negative differential electrical resistivity over a range of values of current and voltage is formed by vapor-depositing a thin layer of a material capable of exhibiting superconductivity on an insulating substrate, establishing electrical connections at opposite ends of the deposited strip, and cooling the alloy into its superconducting range. The device will exhibit negative differential resistivity when biased in the current-induced resistive state

  4. The Alphabet Soup of HIV Reservoir Markers.

    Science.gov (United States)

    Sharaf, Radwa R; Li, Jonathan Z

    2017-04-01

    Despite the success of antiretroviral therapy in suppressing HIV, life-long therapy is required to avoid HIV reactivation from long-lived viral reservoirs. Currently, there is intense interest in searching for therapeutic interventions that can purge the viral reservoir to achieve complete remission in HIV patients off antiretroviral therapy. The evaluation of such interventions relies on our ability to accurately and precisely measure the true size of the viral reservoir. In this review, we assess the most commonly used HIV reservoir assays, as a clear understanding of the strengths and weaknesses of each is vital for the accurate interpretation of results and for the development of improved assays. The quantification of intracellular or plasma HIV RNA or DNA levels remains the most commonly used tests for the characterization of the viral reservoir. While cost-effective and high-throughput, these assays are not able to differentiate between replication-competent or defective fractions or quantify the number of infected cells. Viral outgrowth assays provide a lower bound for the fraction of cells that can produce infectious virus, but these assays are laborious, expensive and substantially underestimate the potential reservoir of replication-competent provirus. Newer assays are now available that seek to overcome some of these problems, including full-length proviral sequencing, inducible HIV RNA assays, ultrasensitive p24 assays and murine adoptive transfer techniques. The development and evaluation of strategies for HIV remission rely upon our ability to accurately and precisely quantify the size of the remaining viral reservoir. At this time, all current HIV reservoir assays have drawbacks such that combinations of assays are generally needed to gain a more comprehensive view of the viral reservoir. The development of novel, rapid, high-throughput assays that can sensitively quantify the levels of the replication-competent HIV reservoir is still needed.

  5. Reservoir Models for Gas Hydrate Numerical Simulation

    Science.gov (United States)

    Boswell, R.

    2016-12-01

    Scientific and industrial drilling programs have now providing detailed information on gas hydrate systems that will increasingly be the subject of field experiments. The need to carefully plan these programs requires reliable prediction of reservoir response to hydrate dissociation. Currently, a major emphasis in gas hydrate modeling is the integration of thermodynamic/hydrologic phenomena with geomechanical response for both reservoir and bounding strata. However, also critical to the ultimate success of these efforts is the appropriate development of input geologic models, including several emerging issues, including (1) reservoir heterogeneity, (2) understanding of the initial petrophysical characteristics of the system (reservoirs and seals), the dynamic evolution of those characteristics during active dissociation, and the interdependency of petrophysical parameters and (3) the nature of reservoir boundaries. Heterogeneity is ubiquitous aspect of every natural reservoir, and appropriate characterization is vital. However, heterogeneity is not random. Vertical variation can be evaluated with core and well log data; however, core data often are challenged by incomplete recovery. Well logs also provide interpretation challenges, particularly where reservoirs are thinly-bedded due to limitation in vertical resolution. This imprecision will extend to any petrophysical measurements that are derived from evaluation of log data. Extrapolation of log data laterally is also complex, and should be supported by geologic mapping. Key petrophysical parameters include porosity, permeability and it many aspects, and water saturation. Field data collected to date suggest that the degree of hydrate saturation is strongly controlled by/dependant upon reservoir quality and that the ratio of free to bound water in the remaining pore space is likely also controlled by reservoir quality. Further, those parameters will also evolve during dissociation, and not necessary in a simple

  6. Reservoir Identification: Parameter Characterization or Feature Classification

    Science.gov (United States)

    Cao, J.

    2017-12-01

    The ultimate goal of oil and gas exploration is to find the oil or gas reservoirs with industrial mining value. Therefore, the core task of modern oil and gas exploration is to identify oil or gas reservoirs on the seismic profiles. Traditionally, the reservoir is identify by seismic inversion of a series of physical parameters such as porosity, saturation, permeability, formation pressure, and so on. Due to the heterogeneity of the geological medium, the approximation of the inversion model and the incompleteness and noisy of the data, the inversion results are highly uncertain and must be calibrated or corrected with well data. In areas where there are few wells or no well, reservoir identification based on seismic inversion is high-risk. Reservoir identification is essentially a classification issue. In the identification process, the underground rocks are divided into reservoirs with industrial mining value and host rocks with non-industrial mining value. In addition to the traditional physical parameters classification, the classification may be achieved using one or a few comprehensive features. By introducing the concept of seismic-print, we have developed a new reservoir identification method based on seismic-print analysis. Furthermore, we explore the possibility to use deep leaning to discover the seismic-print characteristics of oil and gas reservoirs. Preliminary experiments have shown that the deep learning of seismic data could distinguish gas reservoirs from host rocks. The combination of both seismic-print analysis and seismic deep learning is expected to be a more robust reservoir identification method. The work was supported by NSFC under grant No. 41430323 and No. U1562219, and the National Key Research and Development Program under Grant No. 2016YFC0601

  7. Seismic Response of Deep Hydrocarbon Bearing Reservoirs: examples from Oso Field and implications for Future Opportunities

    International Nuclear Information System (INIS)

    Oluwasusi, A. B.; Hussey, V.; Goulding, F. J.

    2002-01-01

    The Oso Field (OML 70) produces approximately 100 TBD of condensate from Miocene age shelfal sand reservoirs at approximately 10,000 feet below sea level. The field was discovered in 1967 while testing a deeply buried fault closure. Reservoirs are normally pressured, exceed 1 Darcy in permeability and range from 50 to 600 feet in thickness.There are seismic amplitudes associated with the shallower reservoirs on the existing conventional 3D dataset; however there are no anomalies associated with the deeper, condensate accumulations.The paper explores the physical rock and fluid properties associated with the Oso reservoirs and the resulting seismic responses. Modelled results have been calibrated with the actual seismic signatures for the water and hydrocarbon bearing zones. Results indicate that the deeper reservoirs exhibit a classic Class II AVG seismic response and that the use of longer offset and angle stack data can help predict the occurrence of these types of reservoirs. Examples of similar accumulations will be shared.Mobil Producing Nigeria is conducting a full reprocessing effort of the existing 3D dataset over the Joint Venture acreage with a goal of identifying and exploiting additional accumulations with Class II AVG seismic response. Preliminary results of the reprocessing over known accumulations will be presented

  8. Reservoir management under geological uncertainty using fast model update

    NARCIS (Netherlands)

    Hanea, R.; Evensen, G.; Hustoft, L.; Ek, T.; Chitu, A.; Wilschut, F.

    2015-01-01

    Statoil is implementing "Fast Model Update (FMU)," an integrated and automated workflow for reservoir modeling and characterization. FMU connects all steps and disciplines from seismic depth conversion to prediction and reservoir management taking into account relevant reservoir uncertainty. FMU

  9. Optimal Threshold Determination for Discriminating Driving Anger Intensity Based on EEG Wavelet Features and ROC Curve Analysis

    Directory of Open Access Journals (Sweden)

    Ping Wan

    2016-08-01

    Full Text Available Driving anger, called “road rage”, has become increasingly common nowadays, affecting road safety. A few researches focused on how to identify driving anger, however, there is still a gap in driving anger grading, especially in real traffic environment, which is beneficial to take corresponding intervening measures according to different anger intensity. This study proposes a method for discriminating driving anger states with different intensity based on Electroencephalogram (EEG spectral features. First, thirty drivers were recruited to conduct on-road experiments on a busy route in Wuhan, China where anger could be inducted by various road events, e.g., vehicles weaving/cutting in line, jaywalking/cyclist crossing, traffic congestion and waiting red light if they want to complete the experiments ahead of basic time for extra paid. Subsequently, significance analysis was used to select relative energy spectrum of β band (β% and relative energy spectrum of θ band (θ% for discriminating the different driving anger states. Finally, according to receiver operating characteristic (ROC curve analysis, the optimal thresholds (best cut-off points of β% and θ% for identifying none anger state (i.e., neutral were determined to be 0.2183 ≤ θ% < 1, 0 < β% < 0.2586; low anger state is 0.1539 ≤ θ% < 0.2183, 0.2586 ≤ β% < 0.3269; moderate anger state is 0.1216 ≤ θ% < 0.1539, 0.3269 ≤ β% < 0.3674; high anger state is 0 < θ% < 0.1216, 0.3674 ≤ β% < 1. Moreover, the discrimination performances of verification indicate that, the overall accuracy (Acc of the optimal thresholds of β% for discriminating the four driving anger states is 80.21%, while 75.20% for that of θ%. The results can provide theoretical foundation for developing driving anger detection or warning devices based on the relevant optimal thresholds.

  10. Critical thresholds of liver function parameters for ketosis prediction in dairy cows using receiver operating characteristic (ROC) analysis.

    Science.gov (United States)

    Sun, Yuhang; Wang, Bo; Shu, Shi; Zhang, Hongyou; Xu, Chuang; Wu, Ling; Xia, Cheng

    2015-01-01

    Fatty liver syndrome and ketosis are important metabolic disorders in high-producing cows during early lactation with fatty liver usually preceding ketosis. To date, parameters for early prediction of the risk of ketosis have not been investigated in China. To determine the predictive value of some parameters on the risk of ketosis in China. In a descriptive study, 48 control and 32 ketotic Holstein Friesian cows were randomly selected from one farm with a serum β-hydroxybutyrate (BHBA) concentration of 1.20 mmol/L as cutoff point. The risk prediction thresholds for ketosis were determined by receiver operating characteristic (ROC) analysis. In line with a high BHBA concentration, blood glucose concentration was significantly lower in ketotic cows compared to control animals (2.77 ± 0.24 versus 3.34 ± 0.03 mmol/L; P = 0.02). Thresholds were more than 0.76 mmol/L for nonesterified fatty acids (NEFA, with 65% sensitivity and 92% specificity), more than 104 U/L for aspartate aminotransferase (AST, 74% and 85%, respectively), less than 140 U/L for cholinesterase (CHE, 75% and 59%, respectively), and more than 3.3 µmol/L for total bilirubin (TBIL, 58% and 83%, respectively). There were significant correlations between BHBA and glucose (R = -4.74), or CHE (R = -0.262), BHBA and NEFA (R = 0.520), or AST (R = 0.525), or TBIL (R = 0.278), or direct bilirubin (DBIL, R = 0.348). AST, CHE, TBIL and NEFA may be useful parameters for risk prediction of ketosis. This study might be of value in addressing novel directions for future research on the connection between ketosis and liver dysfunction.

  11. A modified Wald interval for the area under the ROC curve (AUC) in diagnostic case-control studies.

    Science.gov (United States)

    Kottas, Martina; Kuss, Oliver; Zapf, Antonia

    2014-02-19

    The area under the receiver operating characteristic (ROC) curve, referred to as the AUC, is an appropriate measure for describing the overall accuracy of a diagnostic test or a biomarker in early phase trials without having to choose a threshold. There are many approaches for estimating the confidence interval for the AUC. However, all are relatively complicated to implement. Furthermore, many approaches perform poorly for large AUC values or small sample sizes. The AUC is actually a probability. So we propose a modified Wald interval for a single proportion, which can be calculated on a pocket calculator. We performed a simulation study to compare this modified Wald interval (without and with continuity correction) with other intervals regarding coverage probability and statistical power. The main result is that the proposed modified Wald intervals maintain and exploit the type I error much better than the intervals of Agresti-Coull, Wilson, and Clopper-Pearson. The interval suggested by Bamber, the Mann-Whitney interval without transformation and also the interval of the binormal AUC are very liberal. For small sample sizes the Wald interval with continuity has a comparable coverage probability as the LT interval and higher power. For large sample sizes the results of the LT interval and of the Wald interval without continuity correction are comparable. If individual patient data is not available, but only the estimated AUC and the total sample size, the modified Wald intervals can be recommended as confidence intervals for the AUC. For small sample sizes the continuity correction should be used.

  12. A Heuristic for Improving Transmedia Exhibition Experience

    DEFF Research Database (Denmark)

    Selvadurai, Vashanth; Rosenstand, Claus Andreas Foss

    2017-01-01

    in the scientific field of designing transmedia experience in an exhibition context that links the pre- and post-activities to the actual visit (during-activities). The result of this study is a preliminary heuristic for establishing a relation between the platform and content complexity in transmedia exhibitions....

  13. Memory and Mourning: An Exhibit History

    Science.gov (United States)

    Eberle, Scott G.

    2005-01-01

    Mounted by the Strong Museum in Rochester, New York, in 1993, and traveling nationally thereafter, the exhibit Memory and Mourning provided historical and contemporary perspectives to help museum guests explore their own reactions to loss and grief. In the process the exhibit's development team encountered a range of philosophical, historical,…

  14. Let's play game exhibitions : A curator's perspective

    NARCIS (Netherlands)

    de Vos, Jesse; Glas, M.A.J.|info:eu-repo/dai/nl/330981447; van Vught, J.F.|info:eu-repo/dai/nl/413532682

    2017-01-01

    The Netherlands Institute for Sound and Vision is home to The Experience, a museum exhibiting the history of media in the Netherlands. For ten months in 2016 and 2017, The Experience hosted a temporary exhibition entitled Let’s YouTube . During the Let’s YouTube game month, we programmed a ten-day

  15. Science Fiction Exhibits as STEM Gateways

    Science.gov (United States)

    Robie, Samantha

    Women continue to hold less than a quarter of all STEM jobs in the United States, prompting many museums to develop programs and exhibits with the express goal of interesting young girls in scientific fields. At the same time, a number of recent museum exhibits have harnessed the popularity of pop culture and science fiction in order to interest general audiences in STEM subject matter, as well as using the exhibits as springboards to expand or shift mission goals and focus. Because science fiction appears to be successful at raising interest in STEM fields, it may be an effective way to garner the interest of young girls in STEM in particular. This research seeks to describe the ways in which museums are currently using science fiction exhibits to interest young girls in STEM fields and careers. Research focused on four institutions across the country hosting three separate exhibits, and included staff interviews and content analysis of exhibit descriptions, promotional materials, a summative evaluation and supplementary exhibit productions. In some ways, science fiction exhibits do serve young girls, primarily through the inclusion of female role models, staff awareness, and prototype testing to ensure interactives are attractive to girls as well as to boys. However, STEM appears to be underutilized, which may be partly due to a concern within the field that the outcome of targeting a specific gender could be construed as "stereotyping".

  16. The Culture of Exhibitions and Conservation

    Directory of Open Access Journals (Sweden)

    Dimitrios Doumas

    2013-11-01

    Full Text Available The article reflects on temporary exhibitions from a theoretical as well as practical perspective. Regarded as a particularly effective mass-communication medium, exhibitions have a dual nature: they are scholarly undertakings, bringing off a curator’s vision and, simultaneously, they are projects with economic implications that need to be well managed and administered. The role of conservation in the making of temporary exhibitions, either in-house or touring, is here discussed in relation to how work is planned and prioritized as well as how time is managed and staff is allocated. Reference to weaknesses that lessen the crucial input of conservation in the decision-making process is also made. Much of the debate, which focuses on art exhibitions, concerns practicalities encountered in a private museum that extend from the very early stages of selecting objects for display to the mounting of an exhibition.

  17. Holland at CERN – Industrial exhibition

    CERN Multimedia

    GS Department

    2010-01-01

    Sponsored by EVD, an agency of the Dutch Ministry of the Economy From 8 to 11 November 2010 Industrial Exhibition Administration Building Bldg. 61 9-00 - 17-30 Twenty seven companies will present their latest technology at the industrial exhibition "Holland at CERN". Dutch industry will exhibit products and technologies which are related to the field of particle physics. Individual interviews will take place directly at the stands in the Main Building. The firms will contact relevant users/technicians but any user wishing to make contact with a particular firm is welcome to use the contact details which are available from each departmental secretariat or at the following URL: http://gs-dep.web.cern.ch/gs-dep/groups/sem/ls/Industrial_Exhibitions.htm#Industrial_exhibitions You will find the list of exhibitors below. LIST OF EXHIBITORS: Schelde Exotech Vernooy BV Triumph Group INCAA Computers DeMaCo Holland bv TNO Science & Industry Janssen Precision Engi...

  18. Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs

    KAUST Repository

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2016-01-01

    Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels

  19. Reflection Phenomena in Underground Pumped Storage Reservoirs

    Directory of Open Access Journals (Sweden)

    Elena Pummer

    2018-04-01

    Full Text Available Energy storage through hydropower leads to free surface water waves in the connected reservoirs. The reason for this is the movement of water between reservoirs at different elevations, which is necessary for electrical energy storage. Currently, the expansion of renewable energies requires the development of fast and flexible energy storage systems, of which classical pumped storage plants are the only technically proven and cost-effective technology and are the most used. Instead of classical pumped storage plants, where reservoirs are located on the surface, underground pumped storage plants with subsurface reservoirs could be an alternative. They are independent of topography and have a low surface area requirement. This can be a great advantage for energy storage expansion in case of environmental issues, residents’ concerns and an unusable terrain surface. However, the reservoirs of underground pumped storage plants differ in design from classical ones for stability and space reasons. The hydraulic design is essential to ensure their satisfactory hydraulic performance. The paper presents a hybrid model study, which is defined here as a combination of physical and numerical modelling to use the advantages and to compensate for the disadvantages of the respective methods. It shows the analysis of waves in ventilated underground reservoir systems with a great length to height ratio, considering new operational aspects from energy supply systems with a great percentage of renewable energies. The multifaceted and narrow design of the reservoirs leads to complex free surface flows; for example, undular and breaking bores arise. The results show excessive wave heights through wave reflections, caused by the impermeable reservoir boundaries. Hence, their knowledge is essential for a successful operational and constructive design of the reservoirs.

  20. Optimal Operation of Hydropower Reservoirs under Climate Change: The Case of Tekeze Reservoir, Eastern Nile

    Directory of Open Access Journals (Sweden)

    Fikru Fentaw Abera

    2018-03-01

    Full Text Available Optimal operation of reservoirs is very essential for water resource planning and management, but it is very challenging and complicated when dealing with climate change impacts. The objective of this paper was to assess existing and future hydropower operation at the Tekeze reservoir in the face of climate change. In this study, a calibrated and validated Soil and Water Assessment Tool (SWAT was used to model runoff inflow into the Tekeze hydropower reservoir under present and future climate scenarios. Inflow to the reservoir was simulated using hydro-climatic data from an ensemble of downscaled climate data based on the Coordinated Regional climate Downscaling Experiment over African domain (CORDEX-Africa with Coupled Intercomparison Project Phase 5 (CMIP5 simulations under Representative Concentration Pathway (RCP4.5 and RCP8.5 climate scenarios. Observed and projected inflows to Tekeze hydropower reservoir were used as input to the US Army Corps of Engineer’s Reservoir Evaluation System Perspective Reservoir Model (HEC-ResPRM, a reservoir operation model, to optimize hydropower reservoir release, storage and pool level. Results indicated that climate change has a clear impact on reservoir inflow and showed increase in annual and monthly inflow into the reservoir except in dry months from May to June under RCP4.5 and RCP8.5 climate scenarios. HEC-ResPRM optimal operation results showed an increase in Tekeze reservoir power storage potential up to 25% and 30% under RCP4.5 and RCP8.5 climate scenarios, respectively. This implies that Tekeze hydropower production will be affected by climate change. This analysis can be used by water resources planners and mangers to develop reservoir operation techniques considering climate change impact to increase power production.

  1. Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

    KAUST Repository

    Katterbauer, Klemens

    2014-01-01

    Enhanced recovery methods have become significant in the industry\\'s drive to increase recovery rates from oil and gas reservoirs. For heavy oil reservoirs, the immobility of the oil at reservoir temperatures, caused by its high viscosity, limits the recovery rates and strains the economic viability of these fields. While thermal recovery methods, such as steam injection or THAI, have extensively been applied in the field, their success has so far been limited due to prohibitive heat losses and the difficulty in controlling the combustion process. Electromagnetic (EM) heating via high-frequency EM radiation has attracted attention due to its wide applicability in different environments, its efficiency, and the improved controllability of the heating process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase recovery rates. Limited research has been undertaken so far to capture the nonlinear reservoir dynamics and significantly varying flow rates for thermally heated heavy oil reservoir that may notably change production rates and render conventional history matching frameworks more challenging. We present a new history matching framework for EM heated heavy oil reservoirs incorporating cross-well seismic imaging. Interfacing an EM heating solver to a reservoir simulator via Andrade’s equation, we couple the system to an ensemble Kalman filter based history matching framework incorporating a cross-well seismic survey module. With increasing power levels and heating applied to the heavy oil reservoirs, reservoir dynamics change considerably and may lead to widely differing production forecasts and increased uncertainty. We have shown that the incorporation of seismic observations into the EnKF framework can significantly enhance reservoir simulations, decrease forecasting

  2. TRANSFER RESERVOIR AS A RAINWATER DRAINAGE SYSTEM

    Directory of Open Access Journals (Sweden)

    Robert Malmur

    2016-06-01

    Full Text Available Intensive rainfalls and snow melting often cause floods in protected areas and overflow the existing sewage systems. Such cases are particularly burdensome for the inhabitants and cause considerable physical losses. One of the possible constructional solutions to ensure the effective outflow of stormwater are transfer reservoirs located between the draining system and a receiver set discussed in this paper. If gravity outflow of sewage is impossible, the initial part of sewage volume is accumulated in the transfer reservoir and then it is transferred into the water receiver set. However, gravity discharge of sewage to the water receiver set occurs through transfer chambers in the transfer reservoir.

  3. Non-Markovian reservoir-dependent squeezing

    International Nuclear Information System (INIS)

    Paavola, J

    2010-01-01

    The squeezing dynamics of a damped harmonic oscillator are studied for different types of environment without making the Markovian approximation. The squeezing dynamics of a coherent state depend on the reservoir spectrum in a unique way that can, in the weak coupling approximation, be analysed analytically. Comparison of squeezing dynamics for ohmic, sub-ohmic and super-ohmic environments is done, showing a clear connection between the squeezing-non-squeezing oscillations and reservoir structure. Understanding the effects occurring due to structured reservoirs is important both from a purely theoretical point of view and in connection with evolving experimental techniques and future quantum computing applications.

  4. A mini-exhibition with maximum content

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    The University of Budapest has been hosting a CERN mini-exhibition since 8 May. While smaller than the main travelling exhibition it has a number of major advantages: its compact design alleviates transport difficulties and makes it easier to find suitable venues in the Member States. Its content can be updated almost instantaneously and it will become even more interactive and high-tech as time goes by.   The exhibition on display in Budapest. The purpose of CERN's new mini-exhibition is to be more interactive and easier to install. Due to its size, the main travelling exhibition cannot be moved around quickly, which is why it stays in the same country for 4 to 6 months. But this means a long waiting list for the other Member States. To solve this problem, the Education Group has designed a new exhibition, which is smaller and thus easier to install. Smaller maybe, but no less rich in content, as the new exhibition conveys exactly the same messages as its larger counterpart. However, in the slimm...

  5. Gasbuggy reservoir evaluation - 1969 report

    International Nuclear Information System (INIS)

    Atkinson, C.H.; Ward, Don C.; Lemon, R.F.

    1970-01-01

    The December 10, 1967, Project Gasbuggy nuclear detonation followed the drilling and testing of two exploratory wells which confirmed reservoir characteristics and suitability of the site. Reentry and gas production testing of the explosive emplacement hole indicated a collapse chimney about 150 feet in diameter extending from the 4,240-foot detonation depth to about 3,900 feet, the top of the 300-foot-thick Pictured Cliffs gas sand. Production tests of the chimney well in the summer of 1968 and during the last 12 months have resulted in a cumulative production of 213 million cubic feet of hydrocarbons, and gas recovery in 20 years is estimated to be 900 million cubic feet, which would be an increase by a factor of at least 5 over estimated recovery from conventional field wells in this low permeability area. At the end of production tests the flow rate was 160,000 cubic feet per day, which is 6 to 7 times that of an average field well in the area. Data from reentry of a pre-shot test well and a new postshot well at distances from the detonation of 300 and 250 feet, respectively, indicate low productivity and consequently low permeability in any fractures at these locations. (author)

  6. Gasbuggy reservoir evaluation - 1969 report

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, C H; Ward, Don C [Bureau of Mines, U.S. Department of the Interior (United States); Lemon, R F [El Paso Natural Gas Company (United States)

    1970-05-01

    The December 10, 1967, Project Gasbuggy nuclear detonation followed the drilling and testing of two exploratory wells which confirmed reservoir characteristics and suitability of the site. Reentry and gas production testing of the explosive emplacement hole indicated a collapse chimney about 150 feet in diameter extending from the 4,240-foot detonation depth to about 3,900 feet, the top of the 300-foot-thick Pictured Cliffs gas sand. Production tests of the chimney well in the summer of 1968 and during the last 12 months have resulted in a cumulative production of 213 million cubic feet of hydrocarbons, and gas recovery in 20 years is estimated to be 900 million cubic feet, which would be an increase by a factor of at least 5 over estimated recovery from conventional field wells in this low permeability area. At the end of production tests the flow rate was 160,000 cubic feet per day, which is 6 to 7 times that of an average field well in the area. Data from reentry of a pre-shot test well and a new postshot well at distances from the detonation of 300 and 250 feet, respectively, indicate low productivity and consequently low permeability in any fractures at these locations. (author)

  7. The information value of early career productivity in mathematics: a ROC analysis of prediction errors in bibliometricly informed decision making.

    Science.gov (United States)

    Lindahl, Jonas; Danell, Rickard

    The aim of this study was to provide a framework to evaluate bibliometric indicators as decision support tools from a decision making perspective and to examine the information value of early career publication rate as a predictor of future productivity. We used ROC analysis to evaluate a bibliometric indicator as a tool for binary decision making. The dataset consisted of 451 early career researchers in the mathematical sub-field of number theory. We investigated the effect of three different definitions of top performance groups-top 10, top 25, and top 50 %; the consequences of using different thresholds in the prediction models; and the added prediction value of information on early career research collaboration and publications in prestige journals. We conclude that early career performance productivity has an information value in all tested decision scenarios, but future performance is more predictable if the definition of a high performance group is more exclusive. Estimated optimal decision thresholds using the Youden index indicated that the top 10 % decision scenario should use 7 articles, the top 25 % scenario should use 7 articles, and the top 50 % should use 5 articles to minimize prediction errors. A comparative analysis between the decision thresholds provided by the Youden index which take consequences into consideration and a method commonly used in evaluative bibliometrics which do not take consequences into consideration when determining decision thresholds, indicated that differences are trivial for the top 25 and the 50 % groups. However, a statistically significant difference between the methods was found for the top 10 % group. Information on early career collaboration and publication strategies did not add any prediction value to the bibliometric indicator publication rate in any of the models. The key contributions of this research is the focus on consequences in terms of prediction errors and the notion of transforming uncertainty

  8. A Data-Driven Method for Selecting Optimal Models Based on Graphical Visualisation of Differences in Sequentially Fitted ROC Model Parameters

    Directory of Open Access Journals (Sweden)

    K S Mwitondi

    2013-05-01

    Full Text Available Differences in modelling techniques and model performance assessments typically impinge on the quality of knowledge extraction from data. We propose an algorithm for determining optimal patterns in data by separately training and testing three decision tree models in the Pima Indians Diabetes and the Bupa Liver Disorders datasets. Model performance is assessed using ROC curves and the Youden Index. Moving differences between sequential fitted parameters are then extracted, and their respective probability density estimations are used to track their variability using an iterative graphical data visualisation technique developed for this purpose. Our results show that the proposed strategy separates the groups more robustly than the plain ROC/Youden approach, eliminates obscurity, and minimizes over-fitting. Further, the algorithm can easily be understood by non-specialists and demonstrates multi-disciplinary compliance.

  9. ROC evaluation of SPECT myocardial lesion detectability with and without single iteration non-uniform Chang attenuation compensation using an anthropomorphic female phantom

    International Nuclear Information System (INIS)

    Jang, S.; Jaszczak, R.J.; Duke Univ. Medical Center, Durham, NC; Gilland, D.R.; Turkington, T.G.; Coleman, R.E.; Tsui, B.M.W.; Metz, C.E.

    1998-01-01

    The purpose of this work was to evaluate lesion detectability with and without nonuniform attenuation compensation (AC) in myocardial perfusion SPECT imaging in women using an anthropomorphic phantom and receiver operating characteristics (ROC) methodology. Breast attenuation causes artifacts in reconstructed images and may increase the difficulty of diagnosis of myocardial perfusion imaging in women. The null hypothesis tested using the ROC study was that nonuniform AC does not change the lesion detectability in myocardial perfusion SPECT imaging in women. The authors used a filtered backprojection (FBP) reconstruction algorithm and Chang's single iteration method for AC. In conclusion, with the proposed myocardial defect model nuclear medicine physicians demonstrated no significant difference for the detection of the anterior wall defect; however, a greater accuracy for the detection of the inferior wall defect was observed without nonuniform AC than with it. Medical physicists did not demonstrate any statistically significant difference in defect detection accuracy with or without nonuniform AC in the female phantom

  10. France at CERN – Industrial exhibition

    CERN Multimedia

    FP Department

    2012-01-01

    Industrial Exhibition Administration Building Bldg 61 – 1st Floor Tuesday 27 March: 9 a.m. – 5.30 p.m. Wednesday 28 March: 9 a.m. – 2 p.m.   About thirty French companies are presenting their latest technological advances during the industrial exhibition "France at CERN", featuring products and technologies specifically related to CERN activities. Individual B2B meetings can be organized with the sales and technical representatives of participating firms and will take place at either the companies’ exhibition stands or in conference rooms in the Main Building. Individuals wishing to make contact with one or more companies must use the contact details available from each secretariat of department or by using this link. B2B meetings will be coordinated by UBIFRANCE. You will also find the list of exhibiting and participating companies online here. This event is sponsored by the French subsidiary of RS Components, the most important distri...

  11. High Quality Virtual Reality for Architectural Exhibitions

    DEFF Research Database (Denmark)

    Kreutzberg, Anette

    2016-01-01

    This paper will summarise the findings from creating and implementing a visually high quality Virtual Reality (VR) experiment as part of an international architecture exhibition. It was the aim to represent the architectural spatial qualities as well as the atmosphere created from combining natural...... and artificial lighting in a prominent not yet built project. The outcome is twofold: Findings concerning the integration of VR in an exhibition space and findings concerning the experience of the virtual space itself. In the exhibition, an important aspect was the unmanned exhibition space, requiring the VR...... experience to be self-explanatory. Observations of different visitor reactions to the unmanned VR experience compared with visitor reactions at guided tours with personal instructions are evaluated. Data on perception of realism, spatial quality and light in the VR model were collected with qualitative...

  12. Investigation on Reservoir Operation of Agricultural Water Resources Management for Drought Mitigation

    Science.gov (United States)

    Cheng, C. L.

    2015-12-01

    Investigation on Reservoir Operation of Agricultural Water Resources Management for Drought Mitigation Chung-Lien Cheng, Wen-Ping Tsai, Fi-John Chang* Department of Bioenvironmental Systems Engineering, National Taiwan University, Da-An District, Taipei 10617, Taiwan, ROC.Corresponding author: Fi-John Chang (changfj@ntu.edu.tw) AbstractIn Taiwan, the population growth and economic development has led to considerable and increasing demands for natural water resources in the last decades. Under such condition, water shortage problems have frequently occurred in northern Taiwan in recent years such that water is usually transferred from irrigation sectors to public sectors during drought periods. Facing the uneven spatial and temporal distribution of water resources and the problems of increasing water shortages, it is a primary and critical issue to simultaneously satisfy multiple water uses through adequate reservoir operations for sustainable water resources management. Therefore, we intend to build an intelligent reservoir operation system for the assessment of agricultural water resources management strategy in response to food security during drought periods. This study first uses the grey system to forecast the agricultural water demand during February and April for assessing future agricultural water demands. In the second part, we build an intelligent water resources system by using the non-dominated sorting genetic algorithm-II (NSGA-II), an optimization tool, for searching the water allocation series based on different water demand scenarios created from the first part to optimize the water supply operation for different water sectors. The results can be a reference guide for adequate agricultural water resources management during drought periods. Keywords: Non-dominated sorting genetic algorithm-II (NSGA-II); Grey System; Optimization; Agricultural Water Resources Management.

  13. Medan Convention & Exhibition Center (Arsitektur Ekspresionisme)

    OpenAIRE

    Iskandar, Nurul Auni

    2015-01-01

    Medan is one of the third largest city in Indonesia, which is currently being developed, and a city with lots of activities. In the city of Medan has a high investment opportunities for a convention, because of its strategic position in Southeast Asia and also supported by the facility and the potential for tourism in North Sumatra, Medan city has the potential for industrial MICE (Meeting, Incentive, Conference, Exhibition). The construction of Medan Convention & Exhibition Cente...

  14. The presentation of energy topics at exhibitions

    International Nuclear Information System (INIS)

    Moergeli, H.P.

    1984-01-01

    The author examines the problems confronting an electricity supply company when trying to communicate its energy policy to the general public at exhibitions and fairs. The company has to convey a message of reliable power supplies, increasing demand, the advantages of nuclear energy, the safe storage of radioactive waste and the need for new generating plants. The author describes some of the displays being used to attract the public to the Bern Power Stations stand at the Bern Exhibition 1984. (R.S.)

  15. An Astrobiology Microbes Exhibit and Education Module

    Science.gov (United States)

    Lindstrom, Marilyn M.; Allen, Jaclyn S.; Stocco, Karen; Tobola, Kay; Olendzenski, Lorraine

    2001-01-01

    Telling the story of NASA-sponsored scientific research to the public in exhibits is best done by partnerships of scientists and museum professionals. Likewise, preparing classroom activities and training teachers to use them should be done by teams of teachers and scientists. Here we describe how we used such partnerships to develop a new astrobiology augmentation to the Microbes! traveling exhibit and a companion education module. "Additional information is contained in the original extended abstract."

  16. Application of three-class ROC analysis to task-based image quality assessment of simultaneous dual-isotope myocardial perfusion SPECT (MPS).

    Science.gov (United States)

    He, Xin; Song, Xiyun; Frey, Eric C

    2008-11-01

    The diagnosis of cardiac disease using dual-isotope myocardial perfusion SPECT (MPS) is based on the defect status in both stress and rest images, and can be modeled as a three-class task of classifying patients as having no, reversible, or fixed perfusion defects. Simultaneous acquisition protocols for dual-isotope MPS imaging have gained much interest due to their advantages including perfect registration of the (201)Tl and (99m)Tc images in space and time, increased patient comfort, and higher clinical throughput. As a result of simultaneous acquisition, however, crosstalk contamination, where photons emitted by one isotope contribute to the image of the other isotope, degrades image quality. Minimizing the crosstalk is important in obtaining the best possible image quality. One way to minimize the crosstalk is to optimize the injected activity of the two isotopes by considering the three-class nature of the diagnostic problem. To effectively do so, we have previously developed a three-class receiver operating characteristic (ROC) analysis methodology that extends and unifies the decision theoretic, linear discriminant analysis, and psychophysical foundations of binary ROC analysis in a three-class paradigm. In this work, we applied the proposed three-class ROC methodology to the assessment of the image quality of simultaneous dual-isotope MPS imaging techniques and the determination of the optimal injected activity combination. In addition to this application, the rapid development of diagnostic imaging techniques has produced an increasing number of clinical diagnostic tasks that involve not only disease detection, but also disease characterization and are thus multiclass tasks. This paper provides a practical example of the application of the proposed three-class ROC analysis methodology to medical problems.

  17. Multi-probe-based resonance-frequency electrical impedance spectroscopy for detection of suspicious breast lesions: improving performance using partial ROC optimization

    Science.gov (United States)

    Lederman, Dror; Zheng, Bin; Wang, Xingwei; Wang, Xiao Hui; Gur, David

    2011-03-01

    We have developed a multi-probe resonance-frequency electrical impedance spectroscope (REIS) system to detect breast abnormalities. Based on assessing asymmetry in REIS signals acquired between left and right breasts, we developed several machine learning classifiers to classify younger women (i.e., under 50YO) into two groups of having high and low risk for developing breast cancer. In this study, we investigated a new method to optimize performance based on the area under a selected partial receiver operating characteristic (ROC) curve when optimizing an artificial neural network (ANN), and tested whether it could improve classification performance. From an ongoing prospective study, we selected a dataset of 174 cases for whom we have both REIS signals and diagnostic status verification. The dataset includes 66 "positive" cases recommended for biopsy due to detection of highly suspicious breast lesions and 108 "negative" cases determined by imaging based examinations. A set of REIS-based feature differences, extracted from the two breasts using a mirror-matched approach, was computed and constituted an initial feature pool. Using a leave-one-case-out cross-validation method, we applied a genetic algorithm (GA) to train the ANN with an optimal subset of features. Two optimization criteria were separately used in GA optimization, namely the area under the entire ROC curve (AUC) and the partial area under the ROC curve, up to a predetermined threshold (i.e., 90% specificity). The results showed that although the ANN optimized using the entire AUC yielded higher overall performance (AUC = 0.83 versus 0.76), the ANN optimized using the partial ROC area criterion achieved substantially higher operational performance (i.e., increasing sensitivity level from 28% to 48% at 95% specificity and/ or from 48% to 58% at 90% specificity).

  18. Assembling evidence for identifying reservoirs of infection.

    Science.gov (United States)

    Viana, Mafalda; Mancy, Rebecca; Biek, Roman; Cleaveland, Sarah; Cross, Paul C; Lloyd-Smith, James O; Haydon, Daniel T

    2014-05-01

    Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in enriching our mechanistic understanding of how reservoirs function and should be embedded as quasi-experimental studies in adaptive management frameworks. Single approaches to the study of reservoirs are unlikely to generate conclusive insights whereas the formal integration of data and methodologies, involving interventions, pathogen genetics, and contemporary surveillance techniques, promises to open up new opportunities to advance understanding of complex multihost systems. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. NYC Reservoirs Watershed Areas (HUC 12)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This NYC Reservoirs Watershed Areas (HUC 12) GIS layer was derived from the 12-Digit National Watershed Boundary Database (WBD) at 1:24,000 for EPA Region 2 and...

  20. determination of verticality of reservoir engineering structure

    African Journals Online (AJOL)

    user

    applications is 3D survey and management of oil and gas facilities and other engineering structures. This recent .... also affect ground water contamination. 2. VERTICALITY ...... The soil, water and concrete in a Reservoir at the foundation bed ...

  1. Reservoir Greenhouse Gas Emissions at Russian HPP

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, M. P.; Elistratov, V. V.; Maslikov, V. I.; Sidorenko, G. I.; Chusov, A. N.; Atrashenok, V. P.; Molodtsov, D. V. [St. Petersburg State Polytechnic University (Russian Federation); Savvichev, A. S. [Russian Academy of Sciences, S. N. Vinogradskii Institute of Microbiology (Russian Federation); Zinchenko, A. V. [A. I. Voeikov Main Geophysical Observatory (Russian Federation)

    2015-05-15

    Studies of greenhouse-gas emissions from the surfaces of the world’s reservoirs, which has demonstrated ambiguity of assessments of the effect of reservoirs on greenhouse-gas emissions to the atmosphere, is analyzed. It is recommended that greenhouse- gas emissions from various reservoirs be assessed by the procedure “GHG Measurement Guidelines for Fresh Water Reservoirs” (2010) for the purpose of creating a data base with results of standardized measurements. Aprogram for research into greenhouse-gas emissions is being developed at the St. Petersburg Polytechnic University in conformity with the IHA procedure at the reservoirs impounded by the Sayano-Shushenskaya and Mainskaya HPP operated by the RusHydro Co.

  2. Refined reservoir description to maximize oil recovery

    International Nuclear Information System (INIS)

    Flewitt, W.E.

    1975-01-01

    To assure maximized oil recovery from older pools, reservoir description has been advanced by fully integrating original open-hole logs and the recently introduced interpretive techniques made available through cased-hole wireline saturation logs. A refined reservoir description utilizing normalized original wireline porosity logs has been completed in the Judy Creek Beaverhill Lake ''A'' Pool, a reefal carbonate pool with current potential productivity of 100,000 BOPD and 188 active wells. Continuous porosity was documented within a reef rim and cap while discontinuous porous lenses characterized an interior lagoon. With the use of pulsed neutron logs and production data a separate water front and pressure response was recognized within discrete environmental units. The refined reservoir description aided in reservoir simulation model studies and quantifying pool performance. A pattern water flood has now replaced the original peripheral bottom water drive to maximize oil recovery

  3. Zooplankton assemblage of Oyun Reservoir, Offa, Nigeria.

    Science.gov (United States)

    Mustapha, Moshood K

    2009-12-01

    The influence of physico-chemical properties of Oyun Reservoir, Offa, Nigeria (a shallow tropical African reservoir) on its zooplankton composition and abundance were investigated at three stations for two years between January 2002 and December 2003. Diversity is not high: only three groups of zooplankton were found: Rotifera with eight genera; and Cladocera and Copepoda with three genera each. Rotifera dominated numerically (71.02%), followed by Cladocera (16.45%) and Copepoda (12.53%). The zooplankton was more prevalent during the rainy season, and there were variations in the composition and abundance along the reservoir continuum. Factors such as temperature, nutrients, food availability, shape and hydrodynamics of the reservoir, as well as reproductive strategies of the organisms, strongly influence the generic composition and population density of zooplankton. Prevention of ecological deterioration of the water body would greatly should result in a more productive water body, rich in zooplankton and with better fisheries.

  4. Data Compression of Hydrocarbon Reservoir Simulation Grids

    KAUST Repository

    Chavez, Gustavo Ivan; Harbi, Badr M.

    2015-01-01

    A dense volumetric grid coming from an oil/gas reservoir simulation output is translated into a compact representation that supports desired features such as interactive visualization, geometric continuity, color mapping and quad representation. A

  5. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence......The freshwater reservoir effect can result in too high radiocarbon ages of samples from lakes and rivers, including the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. In my talk, I will explain the causes and consequences of this effect. Two...... caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany....

  6. Assembling evidence for identifying reservoirs of infection

    Science.gov (United States)

    Mafalda, Viana; Rebecca, Mancy; Roman, Biek; Sarah, Cleaveland; Cross, Paul C.; James O, Lloyd-Smith; Daniel T, Haydon

    2014-01-01

    Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in enriching our mechanistic understanding of how reservoirs function and should be embedded as quasi-experimental studies in adaptive management frameworks. Single approaches to the study of reservoirs are unlikely to generate conclusive insights whereas the formal integration of data and methodologies, involving interventions, pathogen genetics, and contemporary surveillance techniques, promises to open up new opportunities to advance understanding of complex multihost systems.

  7. Lower Palaeozoic reservoirs of North Africa

    Energy Technology Data Exchange (ETDEWEB)

    Crossley, R.; McDougall, N. [Robertson Research International Ltd., Llandudno, Conwy (United Kingdom)

    1998-12-31

    This paper provides an overview of features considered significant in the exploration and development of Lower Palaeozoic reservoirs of North Africa. Information is derived from a review of literature on the Lower Palaeozoic successions of North Africa, combined with outcrop observations from the Anti Atlas mountains of Morocco. The focus of the exploration-oriented part of the review is on identification of potential traps other than two-way structural dip closure. Stratigraphic elements described include depositional models of reservoir facies, tectonic unconformities and possible eustatic unconformities. Cases of established or potential trapping by post-depositional faulting by diagenesis and by hydrodynamic flow are examined. Development-related topics highlighted include the impact on reservoir matrix quality of burial diagenesis and of palaeo-weathering at the Hercynian unconformity. Other issues discussed which additionally affect producibility from the reservoir matrix include tectonic fracturing, palaeotopography and unloading fracturing at the Hercynian unconformity, and induced fracturing within the present stress regimes. (author)

  8. 49 CFR 393.50 - Reservoirs required.

    Science.gov (United States)

    2010-10-01

    ... using air or vacuum braking must have either reserve capacity, or a reservoir, that would enable the... have a condensate drain valve that can be manually operated. Automatic condensate drain valves may be...

  9. Flow of a stream through a reservoir

    International Nuclear Information System (INIS)

    Sauerwein, K.

    1967-01-01

    If a reservoir is fed from a single source, which may not always be pure, the extent to which the inflowing stream mixes with the water in the reservoir is important for the quality of the water supplied by the reservoir. This question was investigated at the Lingese Reservoir, containing between one and two million cubic metres of water, in the Bergisches Land (North Rhine-Westphalia). The investigation was carried out at four different seasons so that the varying effects of the stream-water temperatures could be studied in relation to the temperature of the reservoir water. The stream was radioactively labelled at the point of inflow into the reservoir, and its flow through the reservoir was measured in length and depth from boats, by means of 1-m-long Geiger counters. In two cases the radioactivity of the outflowing water was also measured at fixed points. A considerable variety of intermixing phenomena were observed; these were mainly of limnological interest. The results of four experiments corresponding to the four different seasons are described in detail. They were as follows: (1) The mid-October experiment where the stream, with a temperature of 8.0 deg. C, was a good 5 deg. C colder than the water of the reservoir, whose temperature was almost uniform, ranging from 13.2 deg. C at the bed to 13.6 deg. C at the surface. (2) The spring experiment (second half of March), when the stream temperature was only 0.3 deg. C below that of the reservoir surface (7.8 deg. C), while the temperature of the bed was 5.8 deg. C. (3) The winter experiment (early December) where at first the temperature of the stream was approximately the same as that of the surface so that, once again, the stream at first flowed 1/2 - 1 m below the surface. During the almost wind-free night a sudden fall in temperature occurred, and the air temperature dropped from 0 deg. C to -12 deg. C. (4) The summer experiment (end of July to mid-August) when the stream was nearly 1 deg. C colder than

  10. bcROCsurface: an R package for correcting verification bias in estimation of the ROC surface and its volume for continuous diagnostic tests.

    Science.gov (United States)

    To Duc, Khanh

    2017-11-18

    Receiver operating characteristic (ROC) surface analysis is usually employed to assess the accuracy of a medical diagnostic test when there are three ordered disease status (e.g. non-diseased, intermediate, diseased). In practice, verification bias can occur due to missingness of the true disease status and can lead to a distorted conclusion on diagnostic accuracy. In such situations, bias-corrected inference tools are required. This paper introduce an R package, named bcROCsurface, which provides utility functions for verification bias-corrected ROC surface analysis. The shiny web application of the correction for verification bias in estimation of the ROC surface analysis is also developed. bcROCsurface may become an important tool for the statistical evaluation of three-class diagnostic markers in presence of verification bias. The R package, readme and example data are available on CRAN. The web interface enables users less familiar with R to evaluate the accuracy of diagnostic tests, and can be found at http://khanhtoduc.shinyapps.io/bcROCsurface_shiny/ .

  11. The role of stenosis ratio as a predictor of surgical satisfaction in patients with lumbar spinal canal stenosis: a receiver-operator characteristic (ROC) curve analysis.

    Science.gov (United States)

    Mohammadi, Hassanreza R; Azimi, Parisa; Benzel, Edward C; Shahzadi, Sohrab; Azhari, Shirzad

    2016-09-01

    The aim of this study was to elucidate independent factors that predict surgical satisfaction in lumbar spinal canal stenosis (LSCS) patients. Patients who underwent surgery were grouped based on the age, gender, duration of symptoms, walking distance, Neurogenic Claudication Outcome Score (NCOS) and the stenosis ratio (SR) described by Lurencin. We recorded on 2-year patient satisfaction using standardized measure. The optimal cut-off points in SR, NCOS and walking distance for predicting surgical satisfaction were estimated from sensitivity and specificity calculations and receiver operator characteristic (ROC) curves. One hundred fifty consecutive patients (51 male, 99 female, mean age 62.4±10.9 years) were followed up for 34±13 months (range 24-49). One, two, three and four level stenosis was observed in 10.7%, 39.3%, 36.0 % and 14.0% of patients, respectively. Post-surgical satisfaction was 78.5% at the 2 years follow up. In ROC curve analysis, the asymptotic significance is less than 0.05 in SR and the optimal cut-off value of SR to predict worsening surgical satisfaction was measured as more than 0.52, with 85.4% sensitivity and 77.4% specificity (AUC 0.798, 95% CI 0.73-0.90; Ppatients with degenerative lumbar stenosis considered for surgical treatment. Using a ROC curve analysis, a radiological feature, the SR, demonstrated superiority in predicting patient satisfaction, compared to functional and clinical characteristics such as walking distance and NCOS.

  12. The validity of using ROC software for analysing visual grading characteristics data: an investigation based on the novel software VGC analyzer

    International Nuclear Information System (INIS)

    Hansson, Jonny; Maansson, Lars Gunnar; Baath, Magnus

    2016-01-01

    The purpose of the present work was to investigate the validity of using single-reader-adapted receiver operating characteristics (ROC) software for analysis of visual grading characteristics (VGC) data. VGC data from four published VGC studies on optimisation of X-ray examinations, previously analysed using ROCFIT, were reanalysed using a recently developed software dedicated to VGC analysis (VGC Analyzer), and the outcomes [the mean and 95 % confidence interval (CI) of the area under the VGC curve (AUC VGC ) and the p-value] were compared. The studies included both paired and non-paired data and were reanalysed both for the fixed-reader and the random-reader situations. The results showed good agreement between the softwares for the mean AUC VGC . For non-paired data, wider CIs were obtained with VGC Analyzer than previously reported, whereas for paired data, the previously reported CIs were similar or even broader. Similar observations were made for the p-values. The results indicate that the use of single-reader-adapted ROC software such as ROCFIT for analysing non-paired VGC data may lead to an increased risk of committing Type I errors, especially in the random-reader situation. On the other hand, the use of ROC software for analysis of paired VGC data may lead to an increased risk of committing Type II errors, especially in the fixed-reader situation. (authors)

  13. limnological study of the Guavio Reservoir (Colombia)

    International Nuclear Information System (INIS)

    Roldan, Gabriel; Bohorquez, Amparo; Catano, Ramiro; Ardila, Jorge I

    2000-01-01

    From September to December 1996, a limnological study of el Guavio reservoir from o to 100m deep was undertaken. Samples of plankton were taken and chlorophyll a determined. The study showed a well-mixed column of water. Dissolved oxygen remained 60% saturation at 100m deep. Values of phosphorus and nitrogen, as well chlorophyll was very low. Phytoplankton and zooplankton were diverse. The main problem of the reservoir is sediments coming from very erossionable surroundings

  14. Pollination Reservoirs in Lowbush Blueberry (Ericales: Ericaceae)

    OpenAIRE

    Venturini, E. M.; Drummond, F. A.; Hoshide, A. K.; Dibble, A. C.; Stack, L. B.

    2017-01-01

    Abstract Pollinator-dependent agriculture heavily relies upon a single pollinator?the honey bee. To diversify pollination strategies, growers are turning to alternatives. Densely planted reservoirs of pollen- and nectar-rich flowers (pollination reservoirs, hereafter ?PRs?) may improve pollination services provided by wild bees. Our focal agroecosystem, lowbush blueberry (Vaccinium angustifolium Aiton), exists in a simple landscape uniquely positioned to benefit from PRs. First, we contrast b...

  15. Ecological operation for Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    Wen-xian Guo

    2011-06-01

    Full Text Available The traditional operation of the Three Gorges Reservoir has mainly focused on water for flood control, power generation, navigation, water supply, and recreation, and given less attention to the negative impacts of reservoir operation on the river ecosystem. In order to reduce the negative influence of reservoir operation, ecological operation of the reservoir should be studied with a focus on maintaining a healthy river ecosystem. This study considered ecological operation targets, including maintaining the river environmental flow and protecting the spawning and reproduction of the Chinese sturgeon and four major Chinese carps. Using flow data from 1900 to 2006 at the Yichang gauging station as the control station data for the Yangtze River, the minimal and optimal river environmental flows were analyzed, and eco-hydrological targets for the Chinese sturgeon and four major Chinese carps in the Yangtze River were calculated. This paper proposes a reservoir ecological operation model, which comprehensively considers flood control, power generation, navigation, and the ecological environment. Three typical periods, wet, normal, and dry years, were selected, and the particle swarm optimization algorithm was used to analyze the model. The results show that ecological operation modes have different effects on the economic benefit of the hydropower station, and the reservoir ecological operation model can simulate the flood pulse for the requirements of spawning of the Chinese sturgeon and four major Chinese carps. According to the results, by adopting a suitable re-operation scheme, the hydropower benefit of the reservoir will not decrease dramatically while the ecological demand is met. The results provide a reference for designing reasonable operation schemes for the Three Gorges Reservoir.

  16. Analog readout for optical reservoir computers

    OpenAIRE

    Smerieri, Anteo; Duport, François; Paquot, Yvan; Schrauwen, Benjamin; Haelterman, Marc; Massar, Serge

    2012-01-01

    Reservoir computing is a new, powerful and flexible machine learning technique that is easily implemented in hardware. Recently, by using a time-multiplexed architecture, hardware reservoir computers have reached performance comparable to digital implementations. Operating speeds allowing for real time information operation have been reached using optoelectronic systems. At present the main performance bottleneck is the readout layer which uses slow, digital postprocessing. We have designed a...

  17. Geophysical monitoring in a hydrocarbon reservoir

    Science.gov (United States)

    Caffagni, Enrico; Bokelmann, Goetz

    2016-04-01

    Extraction of hydrocarbons from reservoirs demands ever-increasing technological effort, and there is need for geophysical monitoring to better understand phenomena occurring within the reservoir. Significant deformation processes happen when man-made stimulation is performed, in combination with effects deriving from the existing natural conditions such as stress regime in situ or pre-existing fracturing. Keeping track of such changes in the reservoir is important, on one hand for improving recovery of hydrocarbons, and on the other hand to assure a safe and proper mode of operation. Monitoring becomes particularly important when hydraulic-fracturing (HF) is used, especially in the form of the much-discussed "fracking". HF is a sophisticated technique that is widely applied in low-porosity geological formations to enhance the production of natural hydrocarbons. In principle, similar HF techniques have been applied in Europe for a long time in conventional reservoirs, and they will probably be intensified in the near future; this suggests an increasing demand in technological development, also for updating and adapting the existing monitoring techniques in applied geophysics. We review currently available geophysical techniques for reservoir monitoring, which appear in the different fields of analysis in reservoirs. First, the properties of the hydrocarbon reservoir are identified; here we consider geophysical monitoring exclusively. The second step is to define the quantities that can be monitored, associated to the properties. We then describe the geophysical monitoring techniques including the oldest ones, namely those in practical usage from 40-50 years ago, and the most recent developments in technology, within distinct groups, according to the application field of analysis in reservoir. This work is performed as part of the FracRisk consortium (www.fracrisk.eu); this project, funded by the Horizon2020 research programme, aims at helping minimize the

  18. Evaluation of an Empirical Reservoir Shape Function to Define Sediment Distributions in Small Reservoirs

    Directory of Open Access Journals (Sweden)

    Bogusław Michalec

    2015-08-01

    Full Text Available Understanding and defining the spatial distribution of sediment deposited in reservoirs is essential not only at the design stage but also during the operation. The majority of research concerns the distribution of sediment deposition in medium and large water reservoirs. Most empirical methods do not provide satisfactory results when applied to the determination of sediment deposition in small reservoirs. Small reservoir’s volumes do not exceed 5 × 106 m3 and their capacity-inflow ratio is less than 10%. Long-term silting measurements of three small reservoirs were used to evaluate the method described by Rahmanian and Banihashemi for predicting sediment distributions in small reservoirs. Rahmanian and Banihashemi stated that their model of distribution of sediment deposition in water reservoir works well for a long duration operation. In the presented study, the silting rate was used in order to determine the long duration operation. Silting rate is a quotient of volume of the sediment deposited in the reservoir and its original volume. It was stated that when the silting rate had reached 50%, the sediment deposition in the reservoir may be described by an empirical reservoir depth shape function (RDSF.

  19. Water in chalk reservoirs: 'friend or foe?'

    International Nuclear Information System (INIS)

    Hjuler, Morten Leth

    2004-01-01

    Most of the petroleum fields in the Norwegian sector of the North Sea are sandstone reservoirs; the oil and gas are trapped in different species of sandstone. But the Ekofisk Field is a chalk reservoir, which really challenges the operator companies. When oil is produced from chalk reservoirs, water usually gets in and the reservoir subsides. The subsidence may be expensive for the oil companies or be used to advantage by increasing the recovery rate. Since 60 per cent of the world's petroleum reserves are located in carbonate reservoirs, it is important to understand what happens as oil and gas are pumped out. Comprehensive studies at the Department of Petroleum Technology and Applied Geophysics at Stavanger University College in Norway show that the mechanical properties of chalk are considerably altered when the pores in the rock become saturated with oil/gas or water under different stress conditions. The processes are extremely complex. The article also maintains that the effects of injecting carbon dioxide from gas power plants into petroleum reservoirs should be carefully studied before this is done extensively

  20. The pollution of the 'iron gate' reservoir

    International Nuclear Information System (INIS)

    Babic-Mladenovic, M.; Varga, S; Popovic, L.; Damjanovic, M.

    2002-01-01

    The paper presents the characteristics of the Iron Gate I (the Djerdap) Water Power and Navigational System, one of the largest in Europe (completed in 1972 by joint efforts of Yugoslavia and Romania). In this paper the attention is devoted to review of the sediment monitoring program and impacts of reservoir sedimentation, as well as to the investigations of water and sediment quality. Special consideration is paid to the issue of sediment pollution research needs. Namely, the hot spot of the 'Iron Gate' sedimentation represents a scarcely known pollution of sediment deposits. The present pollution probably is considerable, since the 'Iron Gate' reservoir drains about 577000 km 2 , with over 80 million inhabitants, and developed municipal and industrial infrastructure. Therefore, in the thirty-year reservoir life various types of sediment-bound pollutants entered and deposited within it. Especially severe incidents happened during 1999 (as a result of NATO bombing campaign) and 2000 (two accidental pollutions in the Tisza river catchment). The study of the 'Iron Gate' reservoir pollution should be prepared in order to enlighten the present state of reservoir sedimentation and pollution. The main objectives of the study are to enhance the government and public awareness of the present environmental state of the 'Iron Gate' reservoir and to serve as a baseline for all future actions. (author)

  1. Massachusetts reservoir simulation tool—User’s manual

    Science.gov (United States)

    Levin, Sara B.

    2016-10-06

    IntroductionThe U.S. Geological Survey developed the Massachusetts Reservoir Simulation Tool to examine the effects of reservoirs on natural streamflows in Massachusetts by simulating the daily water balance of reservoirs. The simulation tool was developed to assist environmental managers to better manage water withdrawals in reservoirs and to preserve downstream aquatic habitats.

  2. Additional diagnostic value of 99Tcm-MIBI imaging over 'cold' nodules in 99Tcm thyroid imaging proved by ROC analysis

    International Nuclear Information System (INIS)

    Mei Ping; Qin Yongde; Wang Saigang; Ruxianguli; Baya; Lv Jie; Xie Bing; Sun Xiaoyan

    2007-01-01

    Objective: More studies have found that 99 Tc m -MIBI thyroid imaging may provide more differential diagnostic value than traditional 99 Tc m O 4 - thyroid imaging. This study attempted to analyze the receiver operating characteristic (ROC) curves to verify the additional diagnostic value of 99 Tc m -MIBI over 99 Tc m O 4 - thyroid imaging in the differentiation of the 'cold' nodules. Methods: Sixty-eight patients initially diagnosed with 'cold' nodules in 99 Tc m O 4 - thyroid scintigraphy were selected for further 99 Tc m -MIBI thyroid imaging at early (15 min after 99 Tc m -MIBI intravenous injection, ER) and delayed phase (2 h after injection, DR). Semi-quantitative analysis was performed using tumor/normal tissue (T/N) ratio both at ER and DR, with 0.8 defined as the threshold for differential diagnoses. In ROC curves analyses, the ratios from tumor/submaxillary gland (T/S) and tumor/heart (T/H) were derived to obtain the most proper differential diagnostic thresholds. Results: Of all patients with the 'cold' nodules, only eight cases were finally diagnosed on pathology with thyroid malignancy, while other 60 were benign. For differential diagnoses, the sensitivity, specificity and accuracy of semi-quantitative 99 Tc m -MIBI thyroid imaging were 100.0%, 76.7% and 79.4% respectively. However, with thresholds of T/N=0.995, T/S=0.995, T/H=1.005 derived from ROC curves for DR 99 Tc m -MIBI imaging, the differential diagnostic sensitivities were 100.0%, 87.5%, 75.0% and the specificities were 90.0%, 85.0%, 83.3% respectively. The areas under the ROC curves were 0.949, 0.876 and 0. 867 respectively for DR, all significantly larger than those of ER. Statistical difference was also evident between threshold values of 0.8 and 0.995 (χ 2 =6.125, P 99 Tc m -MIBI thyroid imaging provide additional diagnostic value over 99 Tc m O 4 - thyroid imaging for the differentiation of the 'cold' nodules. For 99 Tc m -MIBI thyroid imaging, DR is more valuable than ER in the ROC

  3. Turning energy around: an interactive exhibition experience

    Directory of Open Access Journals (Sweden)

    Sarah Kellberg

    2018-05-01

    Full Text Available A transition from the fossil-fuel driven to a sustainable energy system is an enormous global challenge: climate change and finite resources require countries all over the world to change their way of producing, transporting and using energy. The Energiewende (energy transition will require major changes in the current energy supply system in Germany – but also worldwide. These changes will not only affect the technical sector but will also include ecological questions, social issues and political matters. Whether any transition is going to favour large scale solutions or decentralised technologies depends on local situations and global interconnections, and above all on a democratic process. Hence energy transition succeeds or fails with the acceptance and participation of society. To deal with this overwhelmingly complex topic and its multi-layered dependencies, the Deutsches Museum has designed an exhibition providing visitors with background knowledge about the necessities and challenges of energy transition, unpicking the links between the different technical, economic and social challenges. The exhibition accomplishes the task with an engaging and facilitating approach while taking into account the highly emotive aspects of energy transition as a societal issue. This paper presents the concept of the travelling exhibition energie.wenden, relating it to the Deutsches Museum´s tradition of exhibitions as well as to the challenge of how to deal with socio-scientific topics in scientific exhibitions.

  4. CERN exhibition a big hit in Bulgaria

    CERN Multimedia

    2005-01-01

    The first CERN exhibition in Bulgaria attracted many visitors. In the first ever CERN exhibition to be held in Bulgaria, over 1,400 visitors, many of them students and young physicists, visited the 10-day event in Sofia. The CERN mini-exhibition took place at the National Earth and Mankind Museum between 8 and 17 November. Permanently staffed by young physicists from Sofia University, there were exhibits on display about research activities at CERN, as well as four additional posters describing Bulgaria's participation. The inauguration took place on the morning of 8 November in the presence of the Vice-Minister for Science and Education, Mrs. Vanya Dobreva, and some 200 guests. A series of short speeches were followed by a visit to the exhibition. CERN's representative at the event, Ray Lewis, was then asked by Professor Matey Mateev, President of the Union of Physicists in Bulgaria, to say a few words on behalf of the Organization. Numerous journalists were also present at the inauguration. A painting enti...

  5. Education or business? - exhibition of human corpses

    Directory of Open Access Journals (Sweden)

    Grzegorz Wróbel

    2017-09-01

    Full Text Available Exhibition "BODY WORLDS" which are presented exhibits of human remains are presented all over the world and are a major problem for the modern man, as presented on the preparations of the human not only serve scientific research, are not transferred to the medical schools to educate future doctors, but they were made available to the general public in the form of commercial and ambiguous. The aim of this study was to assess the ethical commercialization of human corpses "BODY WORLDS" exhibitions. Individual approach to the problems presented the dignity and value of human remains after death, of course, strongly related to the professed worldview. In the exhibits can be seen in both the scientific interest anatomical structures, as well as desecrated human remains or beautiful by its functional perfection of the body, understood also in terms of art. The question of ethics determines the right to decide for themselves, on the other hand, allows you to protect bodily integrity even after death. "BODY WORLDS" exhibition goes for the moral and ethical boundaries. In terms of people Gunther von Hagens for plastination of human remains which became a very profitable business, and its current activities defined as "plastination business" should be firmly said about the lack of moral principles.

  6. An environmental data base for all Hydro-Quebec reservoirs

    International Nuclear Information System (INIS)

    Demers, C.

    1988-01-01

    Hydro-Quebec has created two management positions specifically for reservoirs, namely Reservoir Ecology Advisor and Reservoir Management Advisor. To assist management decisions, a means was required of bringing together all existing environmental information for each reservoir operated by Hydro-Quebec, including storage reservoirs, auxiliary reservoirs and forebays. A relational database using Reflex software was developed on a network of Macintosh computers. The database contains five blocks of information: general information, and physical, physiochemical, biologic and socioeconomic characteristics for each reservoir. Data will be collected on over 100 sites, and the tool will form the basis for developing a medium-range study program on reservoir ecology. The program must take into account the physical, biological and socioeconomic aspects of the environment, as well as the concerns of management personnel operating the reservoirs, the local population, reservoir users, and various government departments. 2 figs

  7. ROC Analysis of Visual Assessments Made in Gated Blood Pool Scans of Patients with Coronary Artery Disease

    International Nuclear Information System (INIS)

    Lee, Kyung Han; Choi, Yoon Ho; Lee, Bum Woo; Moon, Dae Hyuk; Chung, June Key; Lee, Myung Chul; Koh, Chang Soon; Koong, Sung Soo

    1989-01-01

    Visual assessment of regional wall motion abnormality (RWMA) by gated blood pol scan (GBPS) serves as an useful parameter in thc diagnosis, functional evaluation, and follow up in various clinical settings, but are still subject to some inherent limitations. On important problem may be the interobserver as well as intraobsever variation that may well be present due to the subjective nature of the interpretations. This study was carried out to determine the reliability and reproducibility of visual assessments made in GBPSs, and to observe the degree to which the results would be influenced by observer variation. Fifty two patients with coronary heart disease had resting GBPS and contrast ventriculography within 4 days apart. Contrast ventriculography showed normal wall motion in 6 patients and the remaining 46 had RWMA in one or more segments. The anterior and left anterolateral views of all 52 GBPSs were analyzed by three independent observers, who selected from 5 scales, their level of confidence that there was RWMA in that segment. Receiver operating characteristic (ROC) curves for each analysis was plotted and the area under the curve (θ) was used as a parameter representing each observer's performance in his interpretations. The findings of contract ventriculographies were used as the standard for RWMA. The apical and inferoapical segments showed the best correlation with contrast ventriculography (θ=0.90-.094, 0.81-0.94, respectively), and the inferior wall showed the poorest correlation (θ=0.70-0.74). The interpretations of the inferior, septal, apical and posteroinferior, segments showed no difference between the observers, but there was significantly better performance in assessment by observer A compared to that by B or C for the anterolateral segments (θ=0.87, 0.78, 0.76, respectively, p<0.01 for A vs B, p<0,05 for A vs C), as well as when all segments were considered altogether (θ=0,88, 0.83, 0.82, respectively, both p<0 05). This was also true for

  8. Diagenesis and reservoir quality of Bhuban sandstones (Neogene), Titas Gas Field, Bengal Basin, Bangladesh

    Science.gov (United States)

    Aminul Islam, M.

    2009-06-01

    This study deals with the diagenesis and reservoir quality of sandstones of the Bhuban Formation located at the Titas Gas Field of Bengal Basin. Petrographic study including XRD, CL, SEM and BSE image analysis and quantitative determination of reservoir properties were carried out for this study. The sandstones are fine to medium-grained, moderately well to well sorted subfeldspathic arenites with subordinate feldspathic and lithic arenites. The diagenetic processes include clay infiltration, compaction and cementation (quartz overgrowth, chlorite, kaolinite, calcite and minor amount of pyrite, dolomite and K-feldspar overgrowth). Quartz is the dominant pore occluding cement and generally occurred as small euhedral crystals, locally as large pyramidal crystals in the primary pores. Pressure solution derived from grain contact is the main contributor of quartz overgrowths. Chlorite occurs as pore-lining and pore filling cement. In some cases, chlorite helps to retain porosity by preventing quartz overgrowth. In some restricted depth interval, pore-occlusion by calcite cement is very much intense. Kaolinite locally developed as vermiform and accelerated the minor porosity loss due to pore-occlusion. Kaolinite/chlorite enhances ineffective microporosity. Kaolinite is a by-product of feldspar leaching in the presence of acidic fluid produced during the maturation of organic matter in the adjacent Miocene or deeper Oligocene source rocks. The relation between diagenesis and reservoir quality is as follows: the initial porosity was decreased by compaction and cementation and then increased by leaching of the metastable grains and dissolution of cement. Good quality reservoir rocks were deposited in fluvial environment and hence quality of reservoir rocks is also environment selective. Porosity and permeability data exhibit good inverse correlation with cement. However, some data points indicate multiple controls on permeability. Reservoir quality is thus controlled by

  9. Distribution, source identification, and ecological risk assessment of heavy metals in wetland soils of a river-reservoir system.

    Science.gov (United States)

    Jiang, Xiaoliang; Xiong, Ziqian; Liu, Hui; Liu, Guihua; Liu, Wenzhi

    2017-01-01

    The majority of rivers in the world have been dammed, and over 45,000 large reservoirs have been constructed for multiple purposes. Riparian and reservoir shorelines are the two most important wetland types in a dammed river. To date, few studies have concerned the heavy metal pollution in wetland soils of these river-reservoir systems. In this study, we measured the concentrations of ten heavy metals (Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, and Zn) in surface soils collected from riparian and reservoir shorelines along the Han River in different seasons. Our results found that the Co, Cu, and Ni concentrations in riparian wetlands were significantly lower than those in reservoir shorelines. In riparian wetlands, only soil Sr concentration significantly increased after summer and autumn submergence. Multivariate statistical analyses demonstrated that Ba and Cd might originate from industrial and mining sources, whereas Sr and Mn predominantly originated from natural rock weathering. The ecological risk assessment analysis indicated that both riparian and reservoir shorelines along the Han River in China exhibited a moderate ecological risk in soil heavy metals. The upper Han River basin is the water resource area of China's Middle Route of the South-to-North Water Transfer Project. Therefore, to control the contamination of heavy metals in wetland soils, more efforts should be focused on reducing the discharge of mining and industrial pollutants into the riparian and reservoir shorelines.

  10. The exploration of the exhibition informatization

    Science.gov (United States)

    Zhang, Jiankang

    2017-06-01

    The construction and management of exhibition informatization is the main task and choke point during the process of Chinese exhibition industry’s transformation and promotion. There are three key points expected to realize a breakthrough during the construction of Chinese exhibition informatization, and the three aspects respectively are adopting service outsourcing to construct and maintain the database, adopting advanced chest card technology to collect various kinds of information, developing statistics analysis to maintain good cutomer relations. The success of Chinese exhibition informatization mainly calls for mature suppliers who can provide construction and maintenance of database, the proven technology, a sense of data security, advanced chest card technology, the ability of data mining and analysis and the ability to improve the exhibition service basing on the commercial information got from the data analysis. Several data security measures are expected to apply during the process of system developing, including the measures of the terminal data security, the internet data security, the media data security, the storage data security and the application data security. The informatization of this process is based on the chest card designing. At present, there are several types of chest card technology: bar code chest card; two-dimension code card; magnetic stripe chest card; smart-chip chest card. The information got from the exhibition data will help the organizers to make relevant service strategies, quantify the accumulated indexes of the customers, and improve the level of the customer’s satisfaction and loyalty, what’s more, the information can also provide more additional services like the commercial trips, VIP ceremonial reception.

  11. Exhibits in libraries a practical guide

    CERN Document Server

    Brown, Mary E

    2005-01-01

    "Ccomprehensive...detailed"--Booklist; "thoroughly reseached...highly recommended"--Journal of Access Services. Library exhibits are more than entertainment for patrons. They can inspire and educate, stimulate an interest that can be explored in a book, or attract visitors who otherwise wouldn't stop by. Displays are also an opportunity for a library to put its creative foot forward or help patrons navigate the facility itself. This comprehensive "how-to" includes everything a librarian or staff member needs to know to put on an exhibit, from hatching ideas to evaluating the end result. Illustrations and photographs show practical methods of planning, labeling and displaying.

  12. Three types of gas hydrate reservoirs in the Gulf of Mexico identified in LWD data

    Science.gov (United States)

    Lee, Myung Woong; Collett, Timothy S.

    2011-01-01

    High quality logging-while-drilling (LWD) well logs were acquired in seven wells drilled during the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II in the spring of 2009. These data help to identify three distinct types of gas hydrate reservoirs: isotropic reservoirs in sands, vertical fractured reservoirs in shale, and horizontally layered reservoirs in silty shale. In general, most gas hydratebearing sand reservoirs exhibit isotropic elastic velocities and formation resistivities, and gas hydrate saturations estimated from the P-wave velocity agree well with those from the resistivity. However, in highly gas hydrate-saturated sands, resistivity-derived gas hydrate-saturation estimates appear to be systematically higher by about 5% over those estimated by P-wave velocity, possibly because of the uncertainty associated with the consolidation state of gas hydrate-bearing sands. Small quantities of gas hydrate were observed in vertical fractures in shale. These occurrences are characterized by high formation resistivities with P-wave velocities close to those of water-saturated sediment. Because the formation factor varies significantly with respect to the gas hydrate saturation for vertical fractures at low saturations, an isotropic analysis of formation factor highly overestimates the gas hydrate saturation. Small quantities of gas hydrate in horizontal layers in shale are characterized by moderate increase in P-wave velocities and formation resistivities and either measurement can be used to estimate gas hydrate saturations.

  13. Analysis and application of classification methods of complex carbonate reservoirs

    Science.gov (United States)

    Li, Xiongyan; Qin, Ruibao; Ping, Haitao; Wei, Dan; Liu, Xiaomei

    2018-06-01

    There are abundant carbonate reservoirs from the Cenozoic to Mesozoic era in the Middle East. Due to variation in sedimentary environment and diagenetic process of carbonate reservoirs, several porosity types coexist in carbonate reservoirs. As a result, because of the complex lithologies and pore types as well as the impact of microfractures, the pore structure is very complicated. Therefore, it is difficult to accurately calculate the reservoir parameters. In order to accurately evaluate carbonate reservoirs, based on the pore structure evaluation of carbonate reservoirs, the classification methods of carbonate reservoirs are analyzed based on capillary pressure curves and flow units. Based on the capillary pressure curves, although the carbonate reservoirs can be classified, the relationship between porosity and permeability after classification is not ideal. On the basis of the flow units, the high-precision functional relationship between porosity and permeability after classification can be established. Therefore, the carbonate reservoirs can be quantitatively evaluated based on the classification of flow units. In the dolomite reservoirs, the average absolute error of calculated permeability decreases from 15.13 to 7.44 mD. Similarly, the average absolute error of calculated permeability of limestone reservoirs is reduced from 20.33 to 7.37 mD. Only by accurately characterizing pore structures and classifying reservoir types, reservoir parameters could be calculated accurately. Therefore, characterizing pore structures and classifying reservoir types are very important to accurate evaluation of complex carbonate reservoirs in the Middle East.

  14. Upper Hiwassee River Basin reservoirs 1989 water quality assessment

    International Nuclear Information System (INIS)

    Fehring, J.P.

    1991-08-01

    The water in the Upper Hiwassee River Basin is slightly acidic and low in conductivity. The four major reservoirs in the Upper Hiwassee River Basin (Apalachia, Hiwassee, Chatuge, and Nottely) are not threatened by acidity, although Nottely Reservoir has more sulfates than the other reservoirs. Nottely also has the highest organic and nutrient concentrations of the four reservoirs. This results in Nottely having the poorest water clarity and the most algal productivity, although clarity as measured by color and secchi depths does not indicate any problem with most water use. However, chlorophyll concentrations indicate taste and odor problems would be likely if the upstream end of Nottely Reservoir were used for domestic water supply. Hiwassee Reservoir is clearer and has less organic and nutrient loading than either of the two upstream reservoirs. All four reservoirs have sufficient algal activity to produce supersaturated dissolved oxygen conditions and relatively high pH values at the surface. All four reservoirs are thermally stratified during the summer, and all but Apalachia have bottom waters depleted in oxygen. The very short residence time of Apalachia Reservoir, less than ten days as compared to over 100 days for the other three reservoirs, results in it being more riverine than the other three reservoirs. Hiwassee Reservoir actually develops three distinct water temperature strata due to the location of the turbine intake. The water quality of all of the reservoirs supports designated uses, but water quality complaints are being received regarding both Chatuge and Nottely Reservoirs and their tailwaters

  15. Reservoir architecture and tough gas reservoir potential of fluvial crevasse-splay deposits

    NARCIS (Netherlands)

    Van Toorenenburg, K.A.; Donselaar, M.E.; Weltje, G.J.

    2015-01-01

    Unconventional tough gas reservoirs in low-net-to-gross fluvial stratigraphic intervals may constitute a secondary source of fossil energy to prolong the gas supply in the future. To date, however, production from these thin-bedded, fine-grained reservoirs has been hampered by the economic risks

  16. PLANET TOPERS: Planets, Tracing the Transfer, Origin, Preservation, and Evolution of their ReservoirS.

    Science.gov (United States)

    Dehant, V; Asael, D; Baland, R M; Baludikay, B K; Beghin, J; Belza, J; Beuthe, M; Breuer, D; Chernonozhkin, S; Claeys, Ph; Cornet, Y; Cornet, L; Coyette, A; Debaille, V; Delvigne, C; Deproost, M H; De WInter, N; Duchemin, C; El Atrassi, F; François, C; De Keyser, J; Gillmann, C; Gloesener, E; Goderis, S; Hidaka, Y; Höning, D; Huber, M; Hublet, G; Javaux, E J; Karatekin, Ö; Kodolanyi, J; Revilla, L Lobo; Maes, L; Maggiolo, R; Mattielli, N; Maurice, M; McKibbin, S; Morschhauser, A; Neumann, W; Noack, L; Pham, L B S; Pittarello, L; Plesa, A C; Rivoldini, A; Robert, S; Rosenblatt, P; Spohn, T; Storme, J -Y; Tosi, N; Trinh, A; Valdes, M; Vandaele, A C; Vanhaecke, F; Van Hoolst, T; Van Roosbroek, N; Wilquet, V; Yseboodt, M

    2016-11-01

    The Interuniversity Attraction Pole (IAP) 'PLANET TOPERS' (Planets: Tracing the Transfer, Origin, Preservation, and Evolution of their Reservoirs) addresses the fundamental understanding of the thermal and compositional evolution of the different reservoirs of planetary bodies (core, mantle, crust, atmosphere, hydrosphere, cryosphere, and space) considering interactions and feedback mechanisms. Here we present the first results after 2 years of project work.

  17. Application of integrated reservoir management and reservoir characterization to optimize infill drilling, Class II

    Energy Technology Data Exchange (ETDEWEB)

    Bergeron, Jack; Blasingame, Tom; Doublet, Louis; Kelkar, Mohan; Freeman, George; Callard, Jeff; Moore, David; Davies, David; Vessell, Richard; Pregger, Brian; Dixon, Bill; Bezant, Bryce

    2000-03-16

    The major purpose of this project was to demonstrate the use of cost effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability carbonate reservoirs such as the North Robertson (Clearfork) Unit.

  18. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, Michael L.; Brown, Raymon L.; Civan, Frauk; Hughes, Richard G.

    2001-08-15

    Research continues on characterizing and modeling the behavior of naturally fractured reservoir systems. Work has progressed on developing techniques for estimating fracture properties from seismic and well log data, developing naturally fractured wellbore models, and developing a model to characterize the transfer of fluid from the matrix to the fracture system for use in the naturally fractured reservoir simulator.

  19. How do exhibition visitors describe aesthetic qualities?

    DEFF Research Database (Denmark)

    Thomsen, Bente Dahl; Ravn, Anders Peter

    2007-01-01

    In this investigation, visitors to an art and design exhibition have used an interactive computer program to express the qualities they consider important for an art or design object (artefact). They have then used the program with their individually selected qualities to assess the artefacts. In...

  20. CERN exhibition wins yet another design prize

    CERN Multimedia

    Joannah Caborn Wengler

    2012-01-01

    The “Universe of Particles” exhibition in CERN’s Globe wins the silver design prize from the German direct business communications association FAMAB.   Not only do tens of thousands of people visit the “Universe of Particles” exhibition each year, but juries for design prizes are crossing its threshold more and more frequently too. In 2011 alone it claimed 8 awards, including winning outright the 2011 Annual Multimedia award, the iF Communication Design for Corporate Architecture award and the Modern Decoration Media award (the Bulletin already reported on some of these in July 2011). The FAMAB award is the latest to join the prestigious list. The jury of FAMAB’s “ADAM 2011” award was particularly impressed by the hands-on nature of the exhibition, which encourages visitors to get interested in science. They also appreciated the way that the space in the Globe is not just a container for the exhibits, but itself ...

  1. 49 CFR 250.2 - Required exhibits.

    Science.gov (United States)

    2010-10-01

    ... carried; and identification of the ten most important industries served. (6) As Exhibit 6, statement as to... application for the financing has been made, evidencing that they have declined the financing unless guaranteed by the Secretary or specifying the terms upon which they will undertake the financing without such...

  2. CCPIT Machinery Exhibition Succeeded in Kuala Lumpur

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ From August 18 to 20, 2005, China Council for the Promotion of International Trade(CCPIT) held China Machinery and Electronics Trade Exhibition, CME 2005 in Kuala Lumpur, the capital of Malaysia on behalf of China, a good job has been done.

  3. CCPIT Machinery Exhibition Succeeded in Kuala Lumpur

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

      From August 18 to 20, 2005, China Council for the Promotion of International Trade(CCPIT) held China Machinery and Electronics Trade Exhibition, CME 2005 in Kuala Lumpur, the capital of Malaysia on behalf of China, a good job has been done.……

  4. Comic Strips to Accompany Science Museum Exhibits

    Science.gov (United States)

    Chung, Beom Sun; Park, Eun-mi; Kim, Sang-Hee; Cho, Sook-kyoung; Chung, Min Suk

    2016-01-01

    Science museums make the effort to create exhibits with amusing explanations. However, existing explanation signs with lengthy text are not appealing, and as such, visitors do not pay attention to them. In contrast, conspicuous comic strips composed of simple drawings and humors can attract science museum visitors. This study attempted to reveal…

  5. 18 CFR 50.7 - Applications: exhibits.

    Science.gov (United States)

    2010-04-01

    ... systems, including the special protective systems' automatic switching or load shedding system; and (ii... transfer capability (NITC); system protection; and system stability. (3) A stability analysis including... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Applications: exhibits...

  6. Reservoir Characterization, Production Characteristics, and Research Needs for Fluvial/Alluvial Reservoirs in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Cole, E.L.; Fowler, M.L.; Jackson, S.R.; Madden, M.P.; Raw-Schatzinger, V.; Salamy, S.P.; Sarathi, P.; Young, M.A.

    1999-04-28

    The Department of Energy's (DOE's) Oil Recovery Field Demonstration Program was initiated in 1992 to maximize the economically and environmentally sound recovery of oil from known domestic reservoirs and to preserve access to this resource. Cost-shared field demonstration projects are being initiated in geology defined reservoir classes which have been prioritized by their potential for incremental recovery and their risk of abandonment. This document defines the characteristics of the fifth geological reservoir class in the series, fluvial/alluvial reservoirs. The reservoirs of Class 5 include deposits of alluvial fans, braided streams, and meandering streams. Deposit morphologies vary as a complex function of climate and tectonics and are characterized by a high degree of heterogeneity to fluid flow as a result of extreme variations in water energy as the deposits formed.

  7. Mercury and methylmercury in reservoirs in Indiana

    Science.gov (United States)

    Risch, Martin R.; Fredericksen, Amanda L.

    2015-01-01

    Mercury (Hg) is an element that occurs naturally, but evidence suggests that human activities have resulted in increased amounts being released to the atmosphere and land surface. When Hg is converted to methylmercury (MeHg) in aquatic ecosystems, MeHg accumulates and increases in the food web so that some fish contain levels which pose a health risk to humans and wildlife that consume these fish. Reservoirs unlike natural lakes, are a part of river systems that are managed for flood control. Data compiled and interpreted for six flood-control reservoirs in Indiana showed a relation between Hg transport, MeHg formation in water, and MeHg in fish that was influenced by physical, chemical, and biological differences among the reservoirs. Existing information precludes a uniform comparison of Hg and MeHg in all reservoirs in the State, but factors and conditions were identified that can indicate where and when Hg and MeHg levels in reservoirs could be highest.

  8. Tracing fluid flow in geothermal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Rose, P.E.; Adams, M.C. [Univ. of Utah, Salt Lake City, UT (United States)

    1997-12-31

    A family of fluorescent compounds, the polycyclic aromatic sulfonates, were evaluated for application in intermediate- and high-temperature geothermal reservoirs. Whereas the naphthalene sulfonates were found to be very thermally stable and reasonably detectable, the amino-substituted naphthalene sulfonates were found to be somewhat less thermally stable, but much more detectable. A tracer test was conducted at the Dixie Valley, Nevada, geothermal reservoir using one of the substituted naphthalene sulfonates, amino G, and fluorescein. Four of 9 production wells showed tracer breakthrough during the first 200 days of the test. Reconstructed tracer return curves are presented that correct for the thermal decay of tracer assuming an average reservoir temperature of 227{degrees}C. In order to examine the feasibility of using numerical simulation to model tracer flow, we developed simple, two-dimensional models of the geothermal reservoir using the numerical simulation programs TETRAD and TOUGH2. By fitting model outputs to measured return curves, we show that numerical reservoir simulations can be calibrated with the tracer data. Both models predict the same order of elution, approximate tracer concentrations, and return curve shapes. Using these results, we propose a method for using numerical models to design a tracer test.

  9. Análisis de puntos de rocío y contenidos de humedad de mezclas gaseosas N2-H2O y CH4-H2O

    OpenAIRE

    D. Bogoya M.; C. Müller, I. Q.; L. R. Oellrich

    1995-01-01

    EI conocimiento actual del contenido de humedad de mezclas gaseosas saturadas es aún incompleto, especialmente en la región de altas presiones y bajas temperaturas. Por tanto se realizaron medidas experimentales de punta de rocío con los sistemas nitrógeno-agua y metano-agua, a presiones de 3 y 6 MPa y a temperaturas de 258 K a 288 K. Los puntos de rocío se determinaron con el método del espejo de punta de rocío y los contenidos de humedad por medio de la titulación de Karl-Fischer. Los valor...

  10. Application of integrated reservoir management and reservoir characterization to optimize infill drilling. Quarterly progress report, June 13, 1995--September 12, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pande, P.K.

    1995-09-12

    At this stage of the reservoir characterization research, the main emphasis is on the geostatistics and reservoir simulation. Progress is reported on geological analysis, reservoir simulation, and reservoir management.

  11. Travelling CERN Exhibition ''When Energy Becomes Matter''

    International Nuclear Information System (INIS)

    2001-01-01

    Full text: The European Laboratory for Nuclear Research (CERN) and the H. Niewodniczanski Institute of Nuclear Physics together with the Institute of Physics of the Jagiellonian University and the University of Mining and Metallurgy, and under the auspices of the Polish National Atomic Energy Agency organized in the Museum of Nature in Cracow from October 16 till December 16, 2000 the exhibition ''When Energy Becomes Matter''. The Office of the ''Festival Cracow 2000'' was the main sponsor of that event. The exhibition was a part of the F estival Cracow 2000'' called ''Festival of Youngsters Cracow 2000''. Invitations, posters and information leaflets were sent to more than 3000 schools in southern Poland. The exhibition was divided into four specially designed quadrants. In the first the visitor was informed what kind of scales are in use to describe the Universe and the atom. The second introduced elementary particles via the cosmic ray demonstrations. Particle acceleration was demonstrated with the help of a TV set. The third segment was devoted to the Large Hadron Collider and its experiments: CMS, ATLAS, ALICE and LHCb. The last segment was an attempt to explain what are quarks, leptons and intermediate bosons. In addition it was also explained what is antimatter and why symmetry is broken in Nature. In one of the rooms we arranged the cinema where five movies was continuously presented. Thanks to the Cracow TV it was possible to prepare Polish translations of the films: B ack to creation , P owers of ten , L HC - time machine , S tars underground , and G eneva event . Another attraction of the exhibition was the Internet room equipped with the help of Polish Telecommunication. The exhibition was open seven days per week from 10 to 17 h. During the working days every 20 minutes a new group of about 25-30 people was visiting the exhibition. Each group was guided by students and PhD students from our Institute, Jagiellonian University and University of Mining

  12. Lithology-dependent In Situ Stress in Heterogeneous Carbonate Reservoirs

    Science.gov (United States)

    Pham, C. N.; Chang, C.

    2017-12-01

    Characterization of in situ stress state for various geomechanical aspects in petroleum development may be particularly difficult in carbonate reservoirs in which rock properties are generally heterogeneous. We demonstrate that the variation of in situ stress in highly heterogeneous carbonate reservoirs is closely related to the heterogeneity in rock mechanical property. The carbonate reservoir studied consists of numerous sequential layers gently folded, exhibiting wide ranges of porosity (0.01 - 0.29) and Young's modulus (25 - 85 GPa) depending on lithology. Wellbore breakouts and drilling-induced tensile fractures (DITFs) observed in the image logs obtained from several wells indicate that the in situ state of stress orientation changes dramatically with depth and location. Even in a wellbore, the azimuth of the maximum horizontal stress changes by as much as 60° within a depth interval of 500 m. This dramatic change in stress orientation is inferred to be due to the contrast in elastic properties between different rock layers which are bent by folding in the reservoir. The horizontal principal stress magnitudes are constrained by back-calculating stress conditions necessary to induce the observed wellbore failures using breakout width and the presence of DITFs. The horizontal stresses vary widely, which cannot be represented by a constant stress gradient with depth. The horizontal principal stress gradient increases with Young's modulus of layer monotonically, indicating that a stiffer layer conveys a higher horizontal stress. This phenomenon can be simulated using a numerical modelling, in which the horizontal stress magnitudes depend on stiffness of individual layers although the applied far-field stress conditions are constant. The numerical results also suggest that the stress concentration at the wellbore wall is essentially higher in a stiffer layer, promoting the possibility of wellbore breakout formation. These results are in agreement with our

  13. Oligo-Miocene reservoir sequence characterization and structuring in the Sisseb El Alem-Kalaa Kebira regions (Northeastern Tunisia)

    Science.gov (United States)

    Houatmia, Faten; Khomsi, Sami; Bédir, Mourad

    2015-11-01

    The Sisseb El Alem-Enfidha basin is located in the northeastern Tunisia, It is borded by Nadhour - Saouaf syncline to the north, Kairouan plain to the south, the Mediterranean Sea to the east and Tunisian Atlassic "dorsale" to the west. Oligocene and Miocene deltaic deposits present the main potential deep aquifers in this basin with high porosity (25%-30%). The interpretation of twenty seismic reflection profiles, calibrated by wire line logging data of twelve oil wells, hydraulic wells and geologic field sections highlighted the impact of tectonics on the structuring geometry of Oligo-Miocene sandstones reservoirs and their distribution in raised structures and subsurface depressions. Miocene seismostratigraphy analysis from Ain Ghrab Formation (Langhian) to the Segui Formation (Quaternary) showed five third-order seismic sequence deposits and nine extended lenticular sandy bodies reservoirs limited by toplap and downlap surfaces unconformities, Oligocene deposits presented also five third- order seismic sequences with five extended lenticular sandy bodies reservoirs. The Depth and the thickness maps of these sequence reservoir packages exhibited the structuring of this basin in sub-basins characterized by important lateral and vertical geometric and thichness variations. Petroleum wells wire line logging correlation with clay volume calculation showed an heterogeneous multilayer reservoirs of Oligocene and Miocene formed by the arrangement of fourteen sandstone bodies being able to be good reservoirs, separated by impermeable clay packages and affected by faults. Reservoirs levels correspond mainly to the lower system tract (LST) of sequences. Intensive fracturing by deep seated faults bounding the different sub-basins play a great role for water surface recharge and inter-layer circulations between affected reservoirs. The total pore volume of the Oligo-Miocene reservoir sandy bodies in the study area, is estimated to about 4 × 1012 m3 and equivalent to 4

  14. Operational trade-offs in reservoir control

    Science.gov (United States)

    Georgakakos, Aris P.

    1993-11-01

    Reservoir operation decisions require constant reevaluation in the face of conflicting objectives, varying hydrologic conditions, and frequent operational policy changes. Optimality is a relative concept very much dependent on the circumstances under which a decision is made. More than anything else, reservoir management authorities need the means to assess the impacts of various operational options. It is their responsibility to define what is desirable after a thorough evaluation of the existing circumstances. This article presents a model designed to generate operational trade-offs common among reservoir systems. The model avoids an all-encompassing problem formulation and distinguishes three operational modes (levels) corresponding to normal, drought, and flood operations. Each level addresses only relevant system elements and uses a static and a dynamic control module to optimize turbine performance within each planning period and temporally. The model is used for planning the operation of the Savannah River System.

  15. Prediction of reservoir compaction and surface subsidence

    Energy Technology Data Exchange (ETDEWEB)

    De Waal, J.A.; Smits, R.M.M.

    1988-06-01

    A new loading-rate-dependent compaction model for unconsolidated clastic reservoirs is presented that considerably improves the accuracy of predicting reservoir rock compaction and surface subsidence resulting from pressure depletion in oil and gas fields. The model has been developed on the basis of extensive laboratory studies and can be derived from a theory relating compaction to time-dependent intergranular friction. The procedure for calculating reservoir compaction from laboratory measurements with the new model is outlined. Both field and laboratory compaction behaviors appear to be described by one single normalized, nonlinear compaction curve. With the new model, the large discrepancies usually observed between predictions based on linear compaction models and actual (nonlinear) field behavior can be explained.

  16. Reservoir Sedimentation: Impact, Extent, and Mitigation

    Science.gov (United States)

    Hadley, Richard F.

    Storage reservoirs play an important role in water resources development throughout the world. The one problem with reservoirs that is universal is the continual reduction in usable capacity caused by siltation. This book reviews the world picture of erosion and sediment yield, the large variations that exist, and the physical phenomena related to reservoir siltation. The book is in the Technical Paper series of The World Bank (Technical Paper 71) and is not a formal publication. Rather, it is intended to be circulated to encourage discussion and comment and to communicate results quickly. The book is reproduced from typescript, but this does not detract from the value of the contents as a useful text for hydrologrsts, engineers, and soil conservationists in developing countries.

  17. Greenhouse gas emissions from hydroelectric reservoirs

    International Nuclear Information System (INIS)

    Rosa, L.P.; Schaeffer, R.

    1994-01-01

    In a recent paper, Rudd et al. have suggested that, per unit of electrical energy produced, greenhouse-gas emissions from some hydroelectric reservoirs in northern Canada may be comparable to emissions from fossil-fuelled power plants. The purpose of this comment is to elaborate these issues further so as to understand the potential contribution of hydroelectric reservoirs to the greenhouse effect. More than focusing on the total budget of carbon emissions (be they in the form of CH 4 or be they in the form of CO 2 ), this requires an evaluation of the accumulated greenhouse effect of gas emissions from hydroelectric reservoirs and fossil-fuelled power plants. Two issues will be considered: (a) global warming potential (GWP) for CH 4 ; and (b) how greenhouse-gas emissions from hydroelectric power plants stand against emissions from fossil-fuelled power plants with respect to global warming

  18. Frameworks for amending reservoir water management

    Science.gov (United States)

    Mower, Ethan; Miranda, Leandro E.

    2013-01-01

    Managing water storage and withdrawals in many reservoirs requires establishing seasonal targets for water levels (i.e., rule curves) that are influenced by regional precipitation and diverse water demands. Rule curves are established as an attempt to balance various water needs such as flood control, irrigation, and environmental benefits such as fish and wildlife management. The processes and challenges associated with amending rule curves to balance multiuse needs are complicated and mostly unfamiliar to non-US Army Corps of Engineers (USACE) natural resource managers and to the public. To inform natural resource managers and the public we describe the policies and process involved in amending rule curves in USACE reservoirs, including 3 frameworks: a general investigation, a continuing authority program, and the water control plan. Our review suggests that water management in reservoirs can be amended, but generally a multitude of constraints and competing demands must be addressed before such a change can be realized.

  19. Oil Reservoir Production Optimization using Optimal Control

    DEFF Research Database (Denmark)

    Völcker, Carsten; Jørgensen, John Bagterp; Stenby, Erling Halfdan

    2011-01-01

    Practical oil reservoir management involves solution of large-scale constrained optimal control problems. In this paper we present a numerical method for solution of large-scale constrained optimal control problems. The method is a single-shooting method that computes the gradients using the adjo...... reservoir using water ooding and smart well technology. Compared to the uncontrolled case, the optimal operation increases the Net Present Value of the oil field by 10%.......Practical oil reservoir management involves solution of large-scale constrained optimal control problems. In this paper we present a numerical method for solution of large-scale constrained optimal control problems. The method is a single-shooting method that computes the gradients using...

  20. ROC analysis for evaluating the detectability of image unsharpness due to the patient's movement. Phantom study comparing preview and diagnostic LCDs

    International Nuclear Information System (INIS)

    Tanaka, Rie; Shiraishi, Junji; Takamori, Miho; Watari, Chihiro

    2011-01-01

    The purpose of this study was to evaluate the detectability of image unsharpness due to a patient's movement, a receiver operating characteristic (ROC) analysis was conducted to compare the diagnostic and preview liquid-crystal displays (LCDs). Phantom images that simulated a patient's movement were obtained by using a moving metronome and acrylic plates with a computed radiography (CR) system. A total of 104 images were classified into five groups according to the degrees of image unsharpness determined based on the metronome velocity and exposure time. In an ROC observer study (n=6), a 2-megapixel diagnostic monochrome LCD (2M-LCD) and a 1.3-megapixel general color LCD for preview (1.3M-LCD) were compared in terms of the detection of image unsharpness due to the movement. A statistical test was performed using the multi-reader multi-case (MRMC) method. In the results, the average areas under the ROC curve values for the detection of image unsharpness using the 2M-LCD and 1.3M-LCD were 0.952 and 0.850, respectively. The detection of image unsharpness using the 2M-LCD was significantly better than that using the 1.3M-LCD (p<0.05). In addition, some images with slight unsharpness were identified correctly only using the 2M-LCD. The results suggest that the low-resolution LCD (id est (i.e.), the 1.3M-LCD for preview) had a limitation in identifying image unsharpness due to the patient's movement. Slight unsharpness could be missed in primary image checks performed on a preview monitor equipped with an imaging system. Therefore, the high-resolution LCD (i.e., a 2M-LCD) is necessary when using radiography for diagnostics. (author)

  1. A comparison of confidence/credible interval methods for the area under the ROC curve for continuous diagnostic tests with small sample size.

    Science.gov (United States)

    Feng, Dai; Cortese, Giuliana; Baumgartner, Richard

    2017-12-01

    The receiver operating characteristic (ROC) curve is frequently used as a measure of accuracy of continuous markers in diagnostic tests. The area under the ROC curve (AUC) is arguably the most widely used summary index for the ROC curve. Although the small sample size scenario is common in medical tests, a comprehensive study of small sample size properties of various methods for the construction of the confidence/credible interval (CI) for the AUC has been by and large missing in the literature. In this paper, we describe and compare 29 non-parametric and parametric methods for the construction of the CI for the AUC when the number of available observations is small. The methods considered include not only those that have been widely adopted, but also those that have been less frequently mentioned or, to our knowledge, never applied to the AUC context. To compare different methods, we carried out a simulation study with data generated from binormal models with equal and unequal variances and from exponential models with various parameters and with equal and unequal small sample sizes. We found that the larger the true AUC value and the smaller the sample size, the larger the discrepancy among the results of different approaches. When the model is correctly specified, the parametric approaches tend to outperform the non-parametric ones. Moreover, in the non-parametric domain, we found that a method based on the Mann-Whitney statistic is in general superior to the others. We further elucidate potential issues and provide possible solutions to along with general guidance on the CI construction for the AUC when the sample size is small. Finally, we illustrate the utility of different methods through real life examples.

  2. A statistical approach to evaluate the performance of cardiac biomarkers in predicting death due to acute myocardial infarction: time-dependent ROC curve

    Science.gov (United States)

    Karaismailoğlu, Eda; Dikmen, Zeliha Günnur; Akbıyık, Filiz; Karaağaoğlu, Ahmet Ergun

    2018-04-30

    Background/aim: Myoglobin, cardiac troponin T, B-type natriuretic peptide (BNP), and creatine kinase isoenzyme MB (CK-MB) are frequently used biomarkers for evaluating risk of patients admitted to an emergency department with chest pain. Recently, time- dependent receiver operating characteristic (ROC) analysis has been used to evaluate the predictive power of biomarkers where disease status can change over time. We aimed to determine the best set of biomarkers that estimate cardiac death during follow-up time. We also obtained optimal cut-off values of these biomarkers, which differentiates between patients with and without risk of death. A web tool was developed to estimate time intervals in risk. Materials and methods: A total of 410 patients admitted to the emergency department with chest pain and shortness of breath were included. Cox regression analysis was used to determine an optimal set of biomarkers that can be used for estimating cardiac death and to combine the significant biomarkers. Time-dependent ROC analysis was performed for evaluating performances of significant biomarkers and a combined biomarker during 240 h. The bootstrap method was used to compare statistical significance and the Youden index was used to determine optimal cut-off values. Results : Myoglobin and BNP were significant by multivariate Cox regression analysis. Areas under the time-dependent ROC curves of myoglobin and BNP were about 0.80 during 240 h, and that of the combined biomarker (myoglobin + BNP) increased to 0.90 during the first 180 h. Conclusion: Although myoglobin is not clinically specific to a cardiac event, in our study both myoglobin and BNP were found to be statistically significant for estimating cardiac death. Using this combined biomarker may increase the power of prediction. Our web tool can be useful for evaluating the risk status of new patients and helping clinicians in making decisions.

  3. Salivary oxytocin concentrations in response to running, sexual self-stimulation, breastfeeding and the TSST: The Regensburg Oxytocin Challenge (ROC) study.

    Science.gov (United States)

    Jong, Trynke R de; Menon, Rohit; Bludau, Anna; Grund, Thomas; Biermeier, Verena; Klampfl, Stefanie M; Jurek, Benjamin; Bosch, Oliver J; Hellhammer, Juliane; Neumann, Inga D

    2015-12-01

    Intranasal oxytocin (OXT) application is emerging as a potential treatment for socio-emotional disorders associated with abnormalities in OXT system (re-) activity. The crucial identification of patients with such abnormalities could be streamlined by the assessment of basal and stimulus-induced OXT concentrations in saliva, using a simple, stress-free sampling procedure (i.e. an OXT challenge test). We therefore established the Regensburg Oxytocin Challenge (ROC) test to further validate salivary OXT concentrations as a practical, reliable and sensitive biomarker. OXT concentrations were quantified by radioimmunoassay in samples collected at home by healthy adult male and female volunteers before and after running ("Run") or sexual self-stimulation ("Sex"). In lactating women, salivary OXT concentrations were quantified before, during and after breastfeeding. Salivary OXT along with salivary cortisol and heart rate were monitored in healthy adult participants undergoing the Trier Social Stress Test (TSST). The home-based "Run" and "Sex" challenges as well as the laboratory-based TSST caused quantifiable, rapid, and consistent increases in salivary OXT (approximately 2.5-fold after 10-15min), which were similar for men and women. Breastfeeding did not result in measurably increased salivary OXT levels, probably because the short pulses of OXT release characteristic for lactation were missed. Taken together, ROC tests reliably assess the responsiveness of the OXT system (i.e., the increase in salivary OXT concentrations as compared to basal levels) to challenges such as "Run" and "Sex" at home or psychosocial stress (TSST) in the laboratory. Further studies with larger sample numbers are essentially needed in order to reveal individual differences in ROC test outcomes depending on, for example, genetic or environmental factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Discriminatory power of MRI for differentiation of adrenal non-adenomas vs adenomas evaluated by means of ROC analysis: Can biopsy be obviated?

    Energy Technology Data Exchange (ETDEWEB)

    Slapa, R.Z.; Jakubowski, W.; Krolicki, L. [Department of Imaging, Warsaw Medical School (Poland); Januszewicz, A. [Department of Hypertension, National Institute of Cardiology, Warsaw (Poland); Kasperlik-Zaluska, A.A. [Department of Endocrinology, Center for Postgraduate Medical Education, Warsaw (Poland); Dabrowska, E.; Feltynowski, T. [Department of Hypertension, Warsaw Medical School, Warsaw (Poland); Fijuth, J. [Department of Teleradiotherapy, Institute of Oncology, Warsaw (Poland); Tarnawski, R. [Department of Radiotherapy, Institute of Oncology, Gliwice Branch, Gliwice (Poland)

    2000-01-01

    The purpose of our study was to evaluate the discriminatory power of MRI in high-field magnet (1.5 T) for differentiation of adrenal non-adenomas vs adenomas assessing the following parameters separately and in combination: mean diameter of adrenal mass; previously described and new ratios as well as index calculated from signal intensity (SI) on SE T2-weighted images, chemical shift imaging (CSI), and Gd-DTPA-enhanced dynamic studies. One hundred eight adrenal masses (36 non-hyperfunctioning adenomas, 27 pheochromocytomas, 23 aldosterone-secreting adenomas, 20 malignant masses and 2 cortisol-secreting adenomas) in 95 patients were evaluated with SE sequences, CSI and Gd-DTPA dynamic studies. Indices and ratios of SI for all examined MRI methods were calculated and examined retrospectively for significance of differences between the groups with calculation of sensitivity and specificity. Receiver operating characteristics (ROC) analysis of calculated parameters in combination was performed. The multifactorial analysis of all four parameters, including size of the tumor, T2{sub liver} index, CSI ratio reflecting lipid content in the tumor and Wo{sub max/last} ratio reflecting maximal washout of contrast agent from the tumor had 100 % sensitivity and 100 % specificity in characterization of adrenal non-adenoma. The best performance of combination of mean tumor diameter with single MRI SI parameter was achieved in combination with T2{sub liver} index for all adrenal masses (area under ROC 0.987) and CSI ratio for non-hyperfunctioning adrenal masses (area under ROC 0.991). Magnetic resonance imaging enables sensitive and specific diagnosis of adrenal non-adenoma. (orig.)

  5. LHC INAUGURATION, LHC Fest highlights: exhibition time!

    CERN Multimedia

    2008-01-01

    David Gross, one of the twenty-one Nobel Laureates who have participated in the project.Tuesday 21 October 2008 Accelerating Nobels Colliding Charm, Atomic Cuisine, The Good Anomaly, A Quark Somewhere on the White Paper, Wire Proliferation, A Tale of Two Liquids … these are just some of the titles given to artworks by Physics Nobel Laureates who agreed to make drawings of their prize-winning discoveries (more or less reluctantly) during a special photo session. Science photographer Volker Steger made portraits of Physics Nobel Laureates and before the photo sessions he asked them to make a drawing of their most important discovery. The result is "Accelerating Nobels", an exhibition that combines unusual portraits of and original drawings by twenty-one Nobel laureates in physics whose work is closely related to CERN and the LHC. This exhibition will be one of the highlights of the LHC celebrations on 21 October in the SM18 hall b...

  6. Exhibition: Women and Sciences by Fiami

    CERN Multimedia

    Globe Info

    2011-01-01

    The 19-panel exhibition is on display at CERN's Microcosm from Monday to Saturday from 10.00 a.m. to 5.00 p.m.   Marie Curie won the Nobel Prize for Chemistry one hundred years ago. She is the only woman ever to win two Nobel Prizes, which is a testament to her remarkable work. But throughout history, women have played a role in science either in their own right or alongside other scientists. In this special exhibition, the comic-strip artist Fiami takes a look back at the relationship between women and science through his portraits of Mileva Einstein, Marie-Anne Lavoisier and, of course, Marie Curie. Fiami has recently published an entire album devoted to Marie Curie. Texts in French All ages - Entrance free Femmes et Sciences is on display at Microcosm: From Wednesday 21 September 2011 to Tuesday 20 December 2011.

  7. Characterization of oil and gas reservoir heterogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a heterogeneity matrix'' based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  8. Kuala Namu Convention And Exhibition Centre

    OpenAIRE

    Gustriana, Trisna

    2017-01-01

    Aerotropolis area development that is expected to accommodate the development of business and commercial appeal and this is the chance for the designer to be able to take advantage of the situation and condition of land as well as possible. So that the revolutionary changes but is able to embrace all stakeholders is the solution needed to development Aerotropolis. Kuala Namu's Convention and Exhibition Center is expected to be a solution for regional development of Kuala Namu a...

  9. 22nd Annual Logistics Conference and Exhibition

    Science.gov (United States)

    2006-04-20

    Bill” Kenwell, Vice President, Sales and Marketing, Maersk 5:30pm-7:30pm Reception in Exhibit Hall Wednesday, April 19, 2006 7:00am-5:30pm...some commercial sales of our products, services and platforms. We provide surface, air, and undersea applications on more than 460 programs for US...diagnostic system & process • Seamless B2B integration with maintenance systems Enabled By… EOATM Overview Sensor Data Maintenance Logs Repair Data Expert

  10. The Factory of the Future, Group Exhibition

    OpenAIRE

    Dean, Lionel T.

    2016-01-01

    3D Printing, The factory of the future, Lieu du Design (centre for Design), Paris This exhibition dedicated entirely to 3D printing technology was billed as “the first in France wholly devoted to exploring the interdisciplinary and multifaceted topic of 3D printing technology and its undeniable influence on everything from industry, to economics, to creative and social issues, demonstrated to the public through achievements in the fields of 3D design, 3D printed architecture, 3D printed fa...

  11. Brazilian air traffic controllers exhibit excessive sleepiness.

    Science.gov (United States)

    Ribas, Valdenilson Ribeiro; de Almeida, Cláudia Ângela Vilela; Martins, Hugo André de Lima; Alves, Carlos Frederico de Oliveira; Alves, Marcos José Pinheiro Cândido; Carneiro, Severino Marcos de Oliveira; Ribas, Valéria Ribeiro; de Vasconcelos, Carlos Augusto Carvalho; Sougey, Everton Botelho; de Castro, Raul Manhães

    2011-01-01

    Excessive sleepiness (ES) is an increased tendency to initiate involuntary sleep for naps at inappropriate times. The objective of this study was to assess ES in air traffic controllers (ATCo). 45 flight protection professionals were evaluated, comprising 30 ATCo, subdivided into ATCo with ten or more years in the profession (ATCo≥10, n=15) and ATCo with less than ten years in the profession (ATCoair traffic controllers exhibit excessive sleepiness.

  12. Naval Meteorology and Oceanography Command exhibit entrance

    Science.gov (United States)

    2000-01-01

    StenniSphere at NASA's John C. Stennis Space Center in Hancock County, Miss., invites visitors to discover why America comes to Stennis Space Center before going into space. Designed to entertain while educating, StenniSphere includes informative displays and exhibits from NASA and other agencies located at Stennis, such as this one from the Naval Meteorology and Oceanography Command. Visitors can 'travel' three-dimensionally under the sea and check on the weather back home in the Weather Center.

  13. Naval Meteorology and Oceanography Command exhibit

    Science.gov (United States)

    2000-01-01

    Designed to entertain while educating, StenniSphere at the John C. Stennis Space Center in Hancock County, Miss., includes informative displays and exhibits from NASA and other agencies located at Stennis, such as this one from the Naval Meteorology and Oceanography Command. Visitors can 'travel' three-dimensionally under the sea and check on the weather back home in the Weather Center. StenniSphere is open free of charge from 9 a.m. to 5 p.m. daily.

  14. Exhibition: Linus Pauling and the Twentieth Century

    CERN Document Server

    2003-01-01

    On April 28 the exhibit Linus Pauling and the Twentieth Century organised by UNIDIR (United Nations Institute for Disarmament Research) and SGI (Soka Gakkai International) as well as with the contributions of CERN and the University of Geneva, opened at the United Nations Office of Geneva. Linus Pauling is the only person to date to have won two unshared Nobel Prizes: Chemistry in 1954 and Peace in 1962. The first was awarded for his landmark research on the nature of the chemical bond and its application in understanding the structure of complex substances. The second one acknowledged his courageous protest against atmospheric nuclear testing and his championship of international peace. The exhibit, for audience of all ages, traces seven decades of Linus Pauling's life and influence on the 20th century. Before starting its European tour at the UNESCO headquarters in Paris, the exhibit opened in 1998 in San Francisco and then travelled within the United-States and to Japan with an attendance of more than one...

  15. Exhibition: Linus Pauling and the Twentieth Century

    CERN Document Server

    2003-01-01

    On April 28 the exhibit Linus Pauling and the Twentieth Century organised by UNIDIR (United Nations Institute for Disarmament Research) and SGI (Soka Gakkai International) as well as with the contributions of CERN and the University of Geneva, opens at the United Nations Office of Geneva. Linus Pauling is the only person to date to have won two unshared Nobel Prizes: Chemistry in 1954 and Peace in 1962. The first was awarded for his landmark research on the nature of the chemical bond and its application in understanding the structure of complex substances. The second one acknowledged his courageous protest against atmospheric nuclear testing and his championship of international peace. The exhibit, for all ages' audiences, traces seven decades of Linus Pauling's life and influence on the 20th century. Before starting its European tour at the UNESCO headquarters in Paris, the exhibit opened in 1998 in San Francisco and then travelled within the United-States and to Japan with an attendance of more than one m...

  16. Bumblebees exhibit the memory spacing effect

    Science.gov (United States)

    Toda, Nicholas R. T.; Song, Jeremy; Nieh, James C.

    2009-10-01

    Associative learning is key to how bees recognize and return to rewarding floral resources. It thus plays a major role in pollinator floral constancy and plant gene flow. Honeybees are the primary model for pollinator associative learning, but bumblebees play an important ecological role in a wider range of habitats, and their associative learning abilities are less well understood. We assayed learning with the proboscis extension reflex (PER), using a novel method for restraining bees (capsules) designed to improve bumblebee learning. We present the first results demonstrating that bumblebees exhibit the memory spacing effect. They improve their associative learning of odor and nectar reward by exhibiting increased memory acquisition, a component of long-term memory formation, when the time interval between rewarding trials is increased. Bombus impatiens forager memory acquisition (average discrimination index values) improved by 129% and 65% at inter-trial intervals (ITI) of 5 and 3 min, respectively, as compared to an ITI of 1 min. Memory acquisition rate also increased with increasing ITI. Encapsulation significantly increases olfactory memory acquisition. Ten times more foragers exhibited at least one PER response during training in capsules as compared to traditional PER harnesses. Thus, a novel conditioning assay, encapsulation, enabled us to improve bumblebee-learning acquisition and demonstrate that spaced learning results in better memory consolidation. Such spaced learning likely plays a role in forming long-term memories of rewarding floral resources.

  17. Exhibition: Dialogue between Science and religion

    CERN Multimedia

    2001-01-01

    Can the theory of the Big Bang reached by physicists and the concept of creation beloved of religion ever be reconciled? The two approaches have at least one point in common: they do not provide a final answer to the mysteries of the birth of the Universe. And this means that dialogue is alays possible between the two. It is to show the potential of such an exchange that Geneva's Société Evangélique organization is opening an exhibition under the title 'Big Bang and Creation', at the Planète Charmilles shopping centre, to run from 19 to 30 March. View of the 'Big Bang and Creation' exhibition. The exhibition is divided into three sections, showing the views of the scientist and those of the believer without setting them up in opposition to one another. In the first section, under a representation of the vault of heaven, the visitor will discover the different ideas explaining the birth of the Universe: Genesis and the Big Bang, and the different dominant theories ...

  18. Art exhibit focuses on African astronomy

    Science.gov (United States)

    Showstack, Randy

    2012-07-01

    Connections between Africans and astronomy are the focus of a new exhibition in the National Museum of African Art in Washington, D. C. "African Cosmos: Stellar Arts," which includes artwork, cultural items, and scientific displays from ancient to contemporary times, is the first major exhibit "that brings together arts and science focused on Africa's contribution to keen observations of the heavens over time," curator Christine Mullen Kreamer said at a 20 June news briefing. Among the exhibit's nearly 100 objects are an ancient Egyptian mummy board that includes a representation of the sky goddess Nut, sculptures by the Dogon people of Mali depicting figures in relation to the cosmos, a video that uses data from two square degrees of the Hubble Space Telescope Cosmic Evolution Survey, and a nearly floor-to-ceiling "Rainbow Serpent" constructed of plastic containers by Benin artist Hazoume. An untitled acrylic painting (Figure 1) by South African Gavin Jantjes evokes a myth of the Khoi San people of southern Africa, as it portrays a girl throwing evening fire embers into the night sky, where they remained as the Milky Way.

  19. Use of the ROC model for optimalization in radiotherapy for head and neck cancers. Pt. 2. Cancer of the oral cavity

    International Nuclear Information System (INIS)

    Maciejewski, B.; Zajusz, A.; Rota, L.

    1993-01-01

    The ROC model is used to estimate optimal radiation treatment for cancer of the oral cavity. For 210 patients with cancer of the oral cavity iso-utility curves and k values were determined for various tumors stages and overall treatment times. Optimal k value decreases from 0.792 to 0.584 when overall treatment time is prolonged from 35 to 49 days. It may suggest that the planning of extra dose to balance the effect of extension of overall treatment time does not really improve therapeutic gain. (author)

  20. Revisión del programa de déficit de somatropina en pediatría en el Hospital Universitario Virgen del Rocío

    OpenAIRE

    Lavaredas, A.; Puerta, R. de la; Álvarez del Vayo, C.

    2013-01-01

    Objetivo: Elaborar una revisión del programa de déficit de somatropina aplicado en pediatría en el Hospital Universitario Virgen del Rocío, utilizando dos grupos de pacientes, los diagnosticados con déficit de esta hormona y los nacidos pequeños para edad gestacional, con la intención de evaluar su efectividad en el primer año de tratamiento. Método: Realización de un estudio retrospectivo de la cohorte de pacientes en tratamiento con la hormona del crecimiento bajo los diagnósticos mencionad...

  1. Controls on Cementation in a Chalk Reservoir

    DEFF Research Database (Denmark)

    Meireles, Leonardo Teixeira Pinto; Hussein, A.; Welch, M.J.

    In this study, we identify different controls on cementation in a chalk reservoir. Biot’s coefficient, a measure of cementation, stiffness and strength in porous rocks, is calculated from logging data (bulk density and sonic Pwave velocity). We show that Biot’s coefficient is correlated...... to the water saturation of the Kraka reservoir and is partly controlled by its stratigraphic sub-units. While the direct causal relationship between Biot’s coefficient and water saturation cannot be extended for Biot’s coefficient and porosity, a correlation is also identified between the two, implying...

  2. Freshwater reservoir effect variability in Northern Germany

    DEFF Research Database (Denmark)

    Philippsen, B.; Heinemeier, J.

    2013-01-01

    The freshwater reservoir effect is a potential problem when radiocarbon dating fish bones, shells, human bones, or food crusts on pottery from sites near rivers or lakes. The reservoir age in hardwater rivers can be up to several thousand years and may be highly variable. Accurate 14C dating of f...... that can also be expected for the past. This knowledge will be applied to the dating of food crusts on pottery from the Mesolithic sites Kayhude at the Alster River and Schlamersdorf at the Trave River, both in Schleswig-Holstein, northern Germany....

  3. HIV-1 Reservoir Association with Immune Activation

    Directory of Open Access Journals (Sweden)

    Alejandro Vallejo

    2015-09-01

    Full Text Available In this issue of EBioMedicine, Ruggiero and colleagues describe immune activation biomarkers associated with the size of the HIV reservoir in a carefully designed cross-sectional study. The cohort consists of a homogeneous sample of HIV-1-infected patients with long-term plasma HIV-1 RNA suppression under antiretroviral treatment (ART. It is crucial to explore the potential utility of biomarkers that are easier (less labor intensive, less expensive to measure than integrated HIV DNA load, in order to quickly and accurately quantify cellular reservoirs of HIV.

  4. Nonlinearities in reservoir engineering: Enhancing quantum correlations

    Science.gov (United States)

    Hu, Xiangming; Hu, Qingping; Li, Lingchao; Huang, Chen; Rao, Shi

    2017-12-01

    There are two decisive factors for quantum correlations in reservoir engineering, but they are strongly reversely dependent on the atom-field nonlinearities. One is the squeezing parameter for the Bogoliubov modes-mediated collective interactions, while the other is the dissipative rates for the engineered collective dissipations. Exemplifying two-level atomic ensembles, we show that the moderate nonlinearities can compromise these two factors and thus enhance remarkably two-mode squeezing and entanglement of different spin atomic ensembles or different optical fields. This suggests that the moderate nonlinearities of the two-level systems are more advantageous for applications in quantum networks associated with reservoir engineering.

  5. Characterization of oil and gas reservoir heterogeneity

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The objective of the cooperative research program is to characterize Alaskan reservoirs in terms of their reserves, physical and chemical properties, geologic configuration and structure, and the development potential. The tasks completed during this period include: (1) geologic reservoir description of Endicott Field; (2) petrographic characterization of core samples taken from selected stratigraphic horizons of the West Sak and Ugnu (Brookian) wells; (3) development of a polydispersed thermodynamic model for predicting asphaltene equilibria and asphaltene precipitation from crude oil-solvent mixtures, and (4) preliminary geologic description of the Milne Point Unit.

  6. A New Method for Fracturing Wells Reservoir Evaluation in Fractured Gas Reservoir

    Directory of Open Access Journals (Sweden)

    Jianchun Guo

    2014-01-01

    Full Text Available Natural fracture is a geological phenomenon widely distributed in tight formation, and fractured gas reservoir stimulation effect mainly depends on the communication of natural fractures. Therefore it is necessary to carry out the evaluation of this reservoir and to find out the optimal natural fractures development wells. By analyzing the interactions and nonlinear relationships of the parameters, it establishes three-level index system of reservoir evaluation and proposes a new method for gas well reservoir evaluation model in fractured gas reservoir on the basis of fuzzy logic theory and multilevel gray correlation. For this method, the Gaussian membership functions to quantify the degree of every factor in the decision-making system and the multilevel gray relation to determine the weight of each parameter on stimulation effect. Finally through fuzzy arithmetic operator between multilevel weights and fuzzy evaluation matrix, score, rank, the reservoir quality, and predicted production will be gotten. Result of this new method shows that the evaluation of the production coincidence rate reaches 80%, which provides a new way for fractured gas reservoir evaluation.

  7. Simulation of Reservoir Sediment Flushing of the Three Gorges Reservoir Using an Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Xueying Li

    2016-05-01

    Full Text Available Reservoir sedimentation and its effect on the environment are the most serious world-wide problems in water resources development and utilization today. As one of the largest water conservancy projects, the Three Gorges Reservoir (TGR has been controversial since its demonstration period, and sedimentation is the major concern. Due to the complex physical mechanisms of water and sediment transport, this study adopts the Error Back Propagation Training Artificial Neural Network (BP-ANN to analyze the relationship between the sediment flushing efficiency of the TGR and its influencing factors. The factors are determined by the analysis on 1D unsteady flow and sediment mathematical model, mainly including reservoir inflow, incoming sediment concentration, reservoir water level, and reservoir release. Considering the distinguishing features of reservoir sediment delivery in different seasons, the monthly average data from 2003, when the TGR was put into operation, to 2011 are used to train, validate, and test the BP-ANN model. The results indicate that, although the sample space is quite limited, the whole sediment delivery process can be schematized by the established BP-ANN model, which can be used to help sediment flushing and thus decrease the reservoir sedimentation.

  8. INCREASING WATERFLOOD RESERVES IN THE WILMINGTON OIL FIELD THROUGH IMPROVED RESERVOIR CHARACTERIZATION AND RESERVOIR MANAGEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Scott Walker; Chris Phillips; Roy Koerner; Don Clarke; Dan Moos; Kwasi Tagbor

    2002-02-28

    This project increased recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs. Transferring technology so that it can be applied in other sections of the Wilmington Field and by operators in other slope and basin reservoirs is a primary component of the project. This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate. Although these reservoirs have been waterflooded over 40 years, researchers have found areas of remaining oil saturation. Areas such as the top sand in the Upper Terminal Zone Fault Block V, the western fault slivers of Upper Terminal Zone Fault Block V, the bottom sands of the Tar Zone Fault Block V, and the eastern edge of Fault Block IV in both the Upper Terminal and Lower Terminal Zones all show significant remaining oil saturation. Each area of interest was uncovered emphasizing a different type of reservoir characterization technique or practice. This was not the original strategy but was necessitated by the different levels of progress in each of the project activities.

  9. Improved characterization of reservoir behavior by integration of reservoir performances data and rock type distributions

    Energy Technology Data Exchange (ETDEWEB)

    Davies, D.K.; Vessell, R.K. [David K. Davies & Associates, Kingwood, TX (United States); Doublet, L.E. [Texas A& M Univ., College Station, TX (United States)] [and others

    1997-08-01

    An integrated geological/petrophysical and reservoir engineering study was performed for a large, mature waterflood project (>250 wells, {approximately}80% water cut) at the North Robertson (Clear Fork) Unit, Gaines County, Texas. The primary goal of the study was to develop an integrated reservoir description for {open_quotes}targeted{close_quotes} (economic) 10-acre (4-hectare) infill drilling and future recovery operations in a low permeability, carbonate (dolomite) reservoir. Integration of the results from geological/petrophysical studies and reservoir performance analyses provide a rapid and effective method for developing a comprehensive reservoir description. This reservoir description can be used for reservoir flow simulation, performance prediction, infill targeting, waterflood management, and for optimizing well developments (patterns, completions, and stimulations). The following analyses were performed as part of this study: (1) Geological/petrophysical analyses: (core and well log data) - {open_quotes}Rock typing{close_quotes} based on qualitative and quantitative visualization of pore-scale features. Reservoir layering based on {open_quotes}rock typing {close_quotes} and hydraulic flow units. Development of a {open_quotes}core-log{close_quotes} model to estimate permeability using porosity and other properties derived from well logs. The core-log model is based on {open_quotes}rock types.{close_quotes} (2) Engineering analyses: (production and injection history, well tests) Material balance decline type curve analyses to estimate total reservoir volume, formation flow characteristics (flow capacity, skin factor, and fracture half-length), and indications of well/boundary interference. Estimated ultimate recovery analyses to yield movable oil (or injectable water) volumes, as well as indications of well and boundary interference.

  10. Sensitivity Analysis of Methane Hydrate Reservoirs: Effects of Reservoir Parameters on Gas Productivity and Economics

    Science.gov (United States)

    Anderson, B. J.; Gaddipati, M.; Nyayapathi, L.

    2008-12-01

    This paper presents a parametric study on production rates of natural gas from gas hydrates by the method of depressurization, using CMG STARS. Seven factors/parameters were considered as perturbations from a base-case hydrate reservoir description based on Problem 7 of the International Methane Hydrate Reservoir Simulator Code Comparison Study led by the Department of Energy and the USGS. This reservoir is modeled after the inferred properties of the hydrate deposit at the Prudhoe Bay L-106 site. The included sensitivity variables were hydrate saturation, pressure (depth), temperature, bottom-hole pressure of the production well, free water saturation, intrinsic rock permeability, and porosity. A two-level (L=2) Plackett-Burman experimental design was used to study the relative effects of these factors. The measured variable was the discounted cumulative gas production. The discount rate chosen was 15%, resulting in the gas contribution to the net present value of a reservoir. Eight different designs were developed for conducting sensitivity analysis and the effects of the parameters on the real and discounted production rates will be discussed. The breakeven price in various cases and the dependence of the breakeven price on the production parameters is given in the paper. As expected, initial reservoir temperature has the strongest positive effect on the productivity of a hydrate deposit and the bottom-hole pressure in the production well has the strongest negative dependence. Also resulting in a positive correlation is the intrinsic permeability and the initial free water of the formation. Negative effects were found for initial hydrate saturation (at saturations greater than 50% of the pore space) and the reservoir porosity. These negative effects are related to the available sensible heat of the reservoir, with decreasing productivity due to decreasing available sensible heat. Finally, we conclude that for the base case reservoir, the break-even price (BEP

  11. DEVELOPMENT OF RESERVOIR CHARACTERIZATION TECHNIQUES AND PRODUCTION MODELS FOR EXPLOITING NATURALLY FRACTURED RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Michael L. Wiggins; Raymon L. Brown; Faruk Civan; Richard G. Hughes

    2002-12-31

    For many years, geoscientists and engineers have undertaken research to characterize naturally fractured reservoirs. Geoscientists have focused on understanding the process of fracturing and the subsequent measurement and description of fracture characteristics. Engineers have concentrated on the fluid flow behavior in the fracture-porous media system and the development of models to predict the hydrocarbon production from these complex systems. This research attempts to integrate these two complementary views to develop a quantitative reservoir characterization methodology and flow performance model for naturally fractured reservoirs. The research has focused on estimating naturally fractured reservoir properties from seismic data, predicting fracture characteristics from well logs, and developing a naturally fractured reservoir simulator. It is important to develop techniques that can be applied to estimate the important parameters in predicting the performance of naturally fractured reservoirs. This project proposes a method to relate seismic properties to the elastic compliance and permeability of the reservoir based upon a sugar cube model. In addition, methods are presented to use conventional well logs to estimate localized fracture information for reservoir characterization purposes. The ability to estimate fracture information from conventional well logs is very important in older wells where data are often limited. Finally, a desktop naturally fractured reservoir simulator has been developed for the purpose of predicting the performance of these complex reservoirs. The simulator incorporates vertical and horizontal wellbore models, methods to handle matrix to fracture fluid transfer, and fracture permeability tensors. This research project has developed methods to characterize and study the performance of naturally fractured reservoirs that integrate geoscience and engineering data. This is an important step in developing exploitation strategies for

  12. Library exhibits and programs boost science education

    Science.gov (United States)

    Dusenbery, Paul B.; Curtis, Lisa

    2012-05-01

    Science museums let visitors explore and discover, but for many families there are barriers—such as cost or distance—that prevent them from visiting museums and experiencing hands-on science, technology, engineering, and mathematics (STEM) learning. Now educators are reaching underserved audiences by developing STEM exhibits and programs for public libraries. With more than 16,000 outlets in the United States, public libraries serve almost every community in the country. Nationwide, they receive about 1.5 billion visits per year, and they offer their services for free.

  13. Temperature changes in Three Gorges Reservoir Area and linkage with Three Gorges Project

    Science.gov (United States)

    Song, Zhen; Liang, Shunlin; Feng, Lian; He, Tao; Song, Xiao-Peng; Zhang, Lei

    2017-05-01

    The Three Gorges Project (TGP) is one of the largest hydroelectric projects throughout the world. It has brought many benefits to the society but also led to endless debates about its environmental and climatic impacts. Monitoring the spatiotemporal variations of temperature in the Three Gorges Reservoir Area (TGRA) is important for understanding the climatic impacts of the TGP. In this study, we used remote sensing-based land surface temperature (LST) and ground-measured air temperature data to investigate temperature changes in the TGRA. Results showed that during the daytime in summer, LST exhibited significant cooling (1-5°C) in the downstream region of the reservoir, whereas LST during the nighttime in winter exhibited significant warming (1-5°C) across the entire reservoir. However, these cooling and warming effects were both locally constrained within 5 km buffer along the reservoir. The changes in air temperature were consistent with those in LST, with 0.67°C cooling in summer and 0.33°C warming in winter. The temperature changes along the reservoir not only resulted from the land-water conversion induced by the dam impounding but were also related to the increase of vegetation cover caused by the ecological restoration projects. Significant warming trends were also found in the upstream of TGRA, especially during the daytime in summer, with up to 5°C for LST and 0.52°C for air temperature. The warming was caused mainly by urban expansion, which was driven in part by the population resettlement of TGP. Based on satellite observations, we investigated the comprehensive climatic impacts of TGP caused by multiple factors.

  14. Fifteenth workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The Fifteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 23--25, 1990. Major topics included: DOE's geothermal research and development program, well testing, field studies, geosciences, geysers, reinjection, tracers, geochemistry, and modeling.

  15. Dissolved methane in Indian freshwater reservoirs

    Digital Repository Service at National Institute of Oceanography (India)

    Narvenkar, G.; Naqvi, S.W.A.; Kurian, S.; Shenoy, D.M.; Pratihary, A.K.; Naik, H.; Patil, S.; Sarkar, A.; Gauns, M.

    of the central part of the Indo- Gangetic Plain just north of the Tropic of Cancer. The eighth – the Bhakra-Nangal Dam is built over the Sutlej River at the foothills of the Himalayas. The reservoirs of these dams vary greatly in size from very small systems...

  16. Do cyanobacterial picoplankton exist in eutrophic reservoirs?

    Czech Academy of Sciences Publication Activity Database

    Komárková, Jaroslava

    2002-01-01

    Roč. 28, - (2002), s. 497-500 ISSN 0368-0770 R&D Projects: GA AV ČR IBS6017004; GA AV ČR IAA6017803; GA AV ČR KSK2005601 Keywords : reservoir * colonial picocynobacteria Subject RIV: DA - Hydrology ; Limnology

  17. Accounting for Greenhouse Gas Emissions from Reservoirs ...

    Science.gov (United States)

    Nearly three decades of research has demonstrated that the impoundment of rivers and the flooding of terrestrial ecosystems behind dams can increase rates of greenhouse gas emission, particularly methane. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories includes a methodology for estimating methane emissions from flooded lands, but the methodology was published as an appendix to be used as a ‘basis for future methodological development’ due to a lack of data. Since the 2006 Guidelines were published there has been a 6-fold increase in the number of peer reviewed papers published on the topic including reports from reservoirs in India, China, Africa, and Russia. Furthermore, several countries, including Iceland, Switzerland, and Finland, have developed country specific methodologies for including flooded lands methane emissions in their National Greenhouse Gas Inventories. This presentation will include a review of the literature on flooded land methane emissions and approaches that have been used to upscale emissions for national inventories. We will also present ongoing research in the United States to develop a country specific methodology. In the U.S., research approaches include: 1) an effort to develop predictive relationships between methane emissions and reservoir characteristics that are available in national databases, such as reservoir size and drainage area, and 2) a national-scale probabilistic survey of reservoir methane em

  18. Landscape runoff, precipitation variation and reservoir limnology

    OpenAIRE

    Geraldes, Ana Maria

    2010-01-01

    Landscape runoff potential impact on reservoir limnology was indirectly evaluated by assessing the effect of precipitation variation on several water quality parameters, on Anabaena (Cyanophyta) and crustacean zooplankton abundances. The obtained results showed that total phosphorus increased with strong precipitation events whereas water transparency presented an opposite trend. Wet periods followed by long dry periods favored Anabaena dominance, which induced a...

  19. Fourteenth workshop geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Miller, F.G.; Brigham, W.E.; Cook, J.W.

    1989-01-01

    The Fourteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 24--26, 1989. Major areas of discussion include: (1) well testing; (2) various field results; (3) geoscience; (4) geochemistry; (5) reinjection; (6) hot dry rock; and (7) numerical modelling. For these workshop proceedings, individual papers are processed separately for the Energy Data Base.

  20. Probing magma reservoirs to improve volcano forecasts

    Science.gov (United States)

    Lowenstern, Jacob B.; Sisson, Thomas W.; Hurwitz, Shaul

    2017-01-01

    When it comes to forecasting eruptions, volcano observatories rely mostly on real-time signals from earthquakes, ground deformation, and gas discharge, combined with probabilistic assessments based on past behavior [Sparks and Cashman, 2017]. There is comparatively less reliance on geophysical and petrological understanding of subsurface magma reservoirs.

  1. Accouting for Greenhouse Gas Emissions from Reservoirs

    Science.gov (United States)

    Beaulieu, J. J.; Deemer, B. R.; Harrison, J. A.; Nietch, C. T.; Waldo, S.

    2016-12-01

    Nearly three decades of research has demonstrated that the impoundment of rivers and the flooding of terrestrial ecosystems behind dams can increase rates of greenhouse gas emission, particularly methane. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories includes a methodology for estimating methane emissions from flooded lands, but the methodology was published as an appendix to be used as a `basis for future methodological development' due to a lack of data. Since the 2006 Guidelines were published there has been a 6-fold increase in the number of peer reviewed papers published on the topic including reports from reservoirs in India, China, Africa, and Russia. Furthermore, several countries, including Iceland, Switzerland, and Finland, have developed country specific methodologies for including flooded lands methane emissions in their National Greenhouse Gas Inventories. This presentation will include a review of the literature on flooded land methane emissions and approaches that have been used to upscale emissions for national inventories. We will also present ongoing research in the United States to develop a country specific methodology. In the U.S., research approaches include: 1) an effort to develop predictive relationships between methane emissions and reservoir characteristics that are available in national databases, such as reservoir size and drainage area, and 2) a national-scale probabilistic survey of reservoir methane emissions linked to the National Lakes Assessment.

  2. Fourteenth workshop geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Miller, F.G.; Brigham, W.E.; Cook, J.W.

    1989-12-31

    The Fourteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 24--26, 1989. Major areas of discussion include: (1) well testing; (2) various field results; (3) geoscience; (4) geochemistry; (5) reinjection; (6) hot dry rock; and (7) numerical modelling. For these workshop proceedings, individual papers are processed separately for the Energy Data Base.

  3. Novel Synechococcus genomes reconstructed from freshwater reservoirs

    Czech Academy of Sciences Publication Activity Database

    Cabello-Yeves, P.J.; Haro-Moreno, J.M.; Martin-Cuadrado, A.B.; Ghai, Rohit; Picazo, A.; Camacho, A.; Rodriguez-Valera, F.

    2017-01-01

    Roč. 8, June (2017), č. článku 1151. ISSN 1664-302X R&D Projects: GA ČR(CZ) GA17-04828S Institutional support: RVO:60077344 Keywords : Synechococcus * picocyanobacteria * freshwater reservoirs * metagenomics * abundance Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.076, year: 2016

  4. Freshwater reservoir effect variability in Northern Germany

    DEFF Research Database (Denmark)

    Philippsen, Bente; Heinemeier, Jan

    2012-01-01

    Kayhude at the river Alster and Schlamersdorf at the river Trave, both in Schleswig-Holstein, Northern Germany. Measurements on modern materials from these rivers may not give a single reservoir age correction that can be applied to archaeological samples, but they will show the order of magnitude...

  5. Adsorption of hydrocarbons in chalk reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, L.

    1996-12-31

    The present work is a study on the wettability of hydrocarbon bearing chalk reservoirs. Wettability is a major factor that influences flow, location and distribution of oil and water in the reservoir. The wettability of the hydrocarbon reservoirs depends on how and to what extent the organic compounds are adsorbed onto the surfaces of calcite, quartz and clay. Organic compounds such as carboxylic acids are found in formation waters from various hydrocarbon reservoirs and in crude oils. In the present investigation the wetting behaviour of chalk is studied by the adsorption of the carboxylic acids onto synthetic calcite, kaolinite, quartz, {alpha}-alumina, and chalk dispersed in an aqueous phase and an organic phase. In the aqueous phase the results clearly demonstrate the differences between the adsorption behaviour of benzoic acid and hexanoic acid onto the surfaces of oxide minerals and carbonates. With NaCl concentration of 0.1 M and with pH {approx_equal} 6 the maximum adsorption of benzoic acid decreases in the order: quartz, {alpha}-alumina, kaolinite. For synthetic calcite and chalk no detectable adsorption was obtaind. In the organic phase the order is reversed. The maximum adsorption of benzoic acid onto the different surfaces decreases in the order: synthetic calcite, chalk, kaolinite and quartz. Also a marked difference in adsorption behaviour between probes with different functional groups onto synthetic calcite from organic phase is observed. The maximum adsorption decreases in the order: benzoic acid, benzyl alcohol and benzylamine. (au) 54 refs.

  6. Exponential rate of convergence in current reservoirs

    OpenAIRE

    De Masi, Anna; Presutti, Errico; Tsagkarogiannis, Dimitrios; Vares, Maria Eulalia

    2015-01-01

    In this paper, we consider a family of interacting particle systems on $[-N,N]$ that arises as a natural model for current reservoirs and Fick's law. We study the exponential rate of convergence to the stationary measure, which we prove to be of the order $N^{-2}$.

  7. The glaciogenic reservoir analogue studies project (GRASP)

    DEFF Research Database (Denmark)

    Moscariello, A.; Moreau, Julien; Vegt, P. van der

    in Quaternary glaciated areas and their nature and sediment composition is critical to drive a sustainable production strategy and assess their vulnerability. Seismic resolution however, often limits the understanding of channel valleys morphology, 3D geometry and internal reservoir distribution, thus...

  8. Parallel Numerical Simulations of Water Reservoirs

    Science.gov (United States)

    Torres, Pedro; Mangiavacchi, Norberto

    2010-11-01

    The study of the water flow and scalar transport in water reservoirs is important for the determination of the water quality during the initial stages of the reservoir filling and during the life of the reservoir. For this scope, a parallel 2D finite element code for solving the incompressible Navier-Stokes equations coupled with scalar transport was implemented using the message-passing programming model, in order to perform simulations of hidropower water reservoirs in a computer cluster environment. The spatial discretization is based on the MINI element that satisfies the Babuska-Brezzi (BB) condition, which provides sufficient conditions for a stable mixed formulation. All the distributed data structures needed in the different stages of the code, such as preprocessing, solving and post processing, were implemented using the PETSc library. The resulting linear systems for the velocity and the pressure fields were solved using the projection method, implemented by an approximate block LU factorization. In order to increase the parallel performance in the solution of the linear systems, we employ the static condensation method for solving the intermediate velocity at vertex and centroid nodes separately. We compare performance results of the static condensation method with the approach of solving the complete system. In our tests the static condensation method shows better performance for large problems, at the cost of an increased memory usage. Performance results for other intensive parts of the code in a computer cluster are also presented.

  9. Studies of Reservoir Hosts for Marburg virus

    DEFF Research Database (Denmark)

    Swanepoel, Robert; Smit, Sheilagh B; Rollin, Pierre E

    2007-01-01

    To determine reservoir hosts for Marburg virus (MARV), we examined the fauna of a mine in northeastern Democratic Republic of the Congo. The mine was associated with a protracted outbreak of Marburg hemorrhagic fever during 1998-2000. We found MARV nucleic acid in 12 bats, comprising 3.0%-3.6% of...

  10. Assessment of diagnostic value of various tumors markers (CEA, CA199, CA50) for colorectal neoplasm with logistic regression and ROC curve

    International Nuclear Information System (INIS)

    Gu Ping; Huang Gang; Han Yuan

    2007-01-01

    Objective: To assess the diagnostic value of CEA, CA199 and CA50 for colorectal neoplasm by logistic regression and ROC curve. Methods: Serum CEA (with CLIA), CA199 (with ECLIA) and CA50 (with IRMA) levels were measured in 75 patients with colorectal cancer, 35 patients with benign colorectal disorders and 49 controls. The area under the ROC curve (AUC)s of CEA, CA199, CA50 from logistic regression results were compared. Results: In the cancer-benign disorder group, the AUC of CA50 was larger than the AUC of CA199. AUC of combined CEA, CA50 was largest: not only larger than any AUC of CEA, CA50, CA199 alone but also larger than the AUC of the combined three markers (0.875 vs 0.604). In cancer-control group, the AUC of combination of CEA, CA199 and CA50 was larger than any AUC of CEA, CA199 or CA50 alone. Both in the cancer-benign disorder group or cancer-control group, the AUC of CEA was larger than the AUC of CA199 or CA50. Conclusion: CEA is of definite value in the diagnosis of colorectal cancer. For differential diagnosis, the combination of CEA and CA50 can give more information, while the combination of three tumor markers is less helpful. As an advanced statistical method, logistic regression can improve the diagnostic sensitivity and specificity. (authors)

  11. The diagnosis of small solitary pulmonary nodule: comparison of standard and inverse digital images on a high resolution monitor using ROC analysis

    International Nuclear Information System (INIS)

    Choi, Byeong Kyoo; Lee, In Sun; Seo, Joon Beom; Lee, Jin Seong; Song, Koun Sik; Lim, Tae Hwan

    2002-01-01

    To study the impact of inversion of soft-copy chest radiographs on the detection of small solitary pulmonary nodules using a high-resolution monitor. The study group consisted of 80 patients who had undergone posterior chest radiography; 40 had a solitary noncalcified pulmonary nodule approximately 1 cm in diameter, and 40 were control subjects. Standard and inverse digital images using the inversion tool on a PACS system were displayed on high-resolution monitors (2048x2560x8 bit). Ten radiologists were requested to rank each image using a five-point scale (1=definitely negative, 3=equivocal or indeterminate, 5=definite nodule), and the data were interpreted using receiver operating characteristic (ROC) analysis. The area under the ROC curve for pooled data of standard image sets was significantly larger than that of inverse image sets (0.8893 and 0.8095, respectively; p 0.05). For detecting small solitary pulmonary nodules, inverse digital images were significantly inferior to standard digital images

  12. A transfer of technology from engineering: use of ROC curves from signal detection theory to investigate information processing in the brain during sensory difference testing.

    Science.gov (United States)

    Wichchukit, Sukanya; O'Mahony, Michael

    2010-01-01

    This article reviews a beneficial effect of technology transfer from Electrical Engineering to Food Sensory Science. Specifically, it reviews the recent adoption in Food Sensory Science of the receiver operating characteristic (ROC) curve, a tool that is incorporated in the theory of signal detection. Its use allows the information processing that takes place in the brain during sensory difference testing to be studied and understood. The review deals with how Signal Detection Theory, also called Thurstonian modeling, led to the adoption of a more sophisticated way of analyzing the data from sensory difference tests, by introducing the signal-to-noise ratio, d', as a fundamental measure of perceived small sensory differences. Generally, the method of computation of d' is a simple matter for some of the better known difference tests like the triangle, duo-trio and 2-AFC. However, there are occasions when these tests are not appropriate and other tests like the same-different and the A Not-A test are more suitable. Yet, for these, it is necessary to understand how the brain processes information during the test before d' can be computed. It is for this task that the ROC curve has a particular use. © 2010 Institute of Food Technologists®

  13. Rocking at 81 and Rolling at 34: ROC Cut-Off Scores for the Negative Acts Questionnaire–Revised in Serbia

    Science.gov (United States)

    Petrović, Ivana B.; Vukelić, Milica; Čizmić, Svetlana

    2017-01-01

    Researchers are still searching for the ways to identify different categories of employees according to their exposure to negative acts and psychological experience of workplace bullying. We followed Notelaers and Einarsen’s application of the ROC analysis to determine the NAQ-R cut-off scores applying a “lower” and “higher” threshold. The main goal of this research was to develop and test different gold standards of personal and organizational relevance in determining the NAQ-R cut-off scores in a specific cultural and economic context of Serbia. Apart from combining self-labeling as a victim with self-perceived health, the objectives were to test the gold standards developed as a combination of self-labeling with life satisfaction, self-labeling with intention to leave and a complex gold standard based on self-labeling, self-perceived health, life satisfaction and intention to leave taken together. The ROC analysis on Serbian workforce data supports applying of different gold standards. For identifying employees in a preliminary stage of bullying, the most applicable was the gold standard based on self-labeling and intention to leave (score 34 and higher). The most accurate identification of victims could be based on the most complex gold standard (score 81 and higher). This research encourages further investigation of gold standards in different cultures. PMID:28119652

  14. Analysis of Sedimentation in Wonogiri Reservoir

    Directory of Open Access Journals (Sweden)

    Tri Joko Inti Budi Santosa

    2016-01-01

    Full Text Available The Wonogiri reservoir which has 730 million cubic meters of total storage, 90 square kilometers of water area, and 1260 square kilometers of catchment area, is located in the Wonogiri Regency, Central Java Province. It was first established in 1981 and began its operation in 1982 with the expectation that it would last for about 100 years. Today (2002 the reservoir has got a serious problem of sedimentation. The sedimentation is so large that it would decrease the capacity storage of the reservoir and would shorten the length of operation. Therefore, it is necessary to predict the sediment that comes into the reservoir. This research would be based on the total sediment calculation of the sedimentation, through some methods, such as echo sounding measured data, land erosion (USLE, the calculation of the sediment in rivers. This research calculates the sediment capacities based on the water flow data and the sediment rating curves in rivers of Keduang, Tirtomoyo, Temon, upstream reach of Bengawan Solo, Alang, and Wuryantoro. The suspended load was calculated based on the sediment rating curves, whereas the bed load was computed as the percentage of the suspended load. The sum of both calculation results would be the total sediment. The calculation result showed that the total sediment which has come into the reservoir is 6.68 million cubic meters per year. As a comparison, the writer noted that the former researcher using echo sounding method done by the Faculty of Geography of the Universitas Gadjah Mada in 1985, it found that the total sediment capacity which came into the reservoir was 6.60 million cubic meters per year or 5.40 mm per year of sheet erosion. The other research using echo sounding method done by JICA in 2000 found that the total sediment which had come into the reservoir was 4.50 million cubic meters per year or 3.50 mm per year of sheet erosion. By knowing the results of calculation of the total sediment, we can learn that

  15. Radiation-related information at science exhibitions

    Energy Technology Data Exchange (ETDEWEB)

    Bannai, Tadaaki [Inst. for Environmental Sciences, Rokkasho, Aomori (Japan)

    1999-09-01

    The aim of the present report was to promote an efficient utilization of science museums providing with educational information concerning radiations. Investigations were made on radiation-related materials exhibited at 38 museums including PR event sites between April 1996 and July 1998 mainly located on Kanto and Tohoku area in Japan. The investigation concerned as to whether the displays on radiation-related material (cosmic rays, X-rays, etc) existed or not, and as to the background of the display as well. As the result, 14 locations had no relevant displays, 10 of them not having things about atomic energy at all. The locations belonging to electricity company mostly had displays related to radiations and atomic energy power generation. A spark chamber was exhibited at 9 locations and a cloud chamber at 3 locations, but only one location among them displayed both. Displays on the actual use of X-radiation were found at 4 locations. Needs to prepare further improved displays exist at the sites visited. (S. Ohno)

  16. CERN Inspires Art in Major New Exhibition

    CERN Document Server

    2001-01-01

    Signatures of the Invisible, an exhibition inspired by CERN, opened at the Atlantis Gallery in London on Thursday, 1 March before going on a world tour. The fruit of a close collaboration between CERN and the London Institute, the exhibition brings together works from many leading European contemporary artists. White wooden boxes on a grey floor... the lids opened, unveiling brilliant white light from a bunch of optical fibres carefully stuck together in the shape of a square. Another holds a treasure of lead glass surrounded by enigmatic black mirrors. What's it all about? Signatures of the Invisible, that's what, a joint project organised by the London Institute, one of the world's largest college of art, and our Laboratory. Damien Foresy from the EST workshop putting finishing touches to the spinning tops of French artist Jérôme Basserode. Monica Sand's boxes are just one of the many works based around materials used in particle detection at CERN that was admired at the opening o...

  17. Children's drawings exhibited in the Globe

    CERN Multimedia

    Elizabeth Roe

    2010-01-01

    "Draw Me A Physicist" has been a success. Members of the public visiting the exhibition in the Globe of Science and Innovation have praised the scientific and creative balance the children of neighbouring France and the Canton of Geneva have obtained through their visit to CERN.   The Draw Me a Physicist exhibition in the Globe For a six-month period 9 to 11-year olds from the Pays de Gex, Meyrin, Satigny and Vernier have been able to enjoy a balance between science and art, through drawing and defining their interpretations of a physicist. In May, eight pairs of drawings from each participating class were selected by the schools to be displayed on the second floor of the Globe. Since the images have been put up, the viewers have enjoyed the contrast between the "before" pictures of vibrant Albert Einsteins to the "after" pictures of casual people sitting in an office. The large room in the Globe has been transformed from a hollow shell int...

  18. Reservoir pressure evolution model during exploration drilling

    Directory of Open Access Journals (Sweden)

    Korotaev B. A.

    2017-03-01

    Full Text Available Based on the analysis of laboratory studies and literature data the method for estimating reservoir pressure in exploratory drilling has been proposed, it allows identify zones of abnormal reservoir pressure in the presence of seismic data on reservoir location depths. This method of assessment is based on developed at the end of the XX century methods using d- and σ-exponentials taking into account the mechanical drilling speed, rotor speed, bit load and its diameter, lithological constant and degree of rocks' compaction, mud density and "regional density". It is known that in exploratory drilling pulsation of pressure at the wellhead is observed. Such pulsation is a consequence of transferring reservoir pressure through clay. In the paper the mechanism for transferring pressure to the bottomhole as well as the behaviour of the clay layer during transmission of excess pressure has been described. A laboratory installation has been built, it has been used for modelling pressure propagation to the bottomhole of the well through a layer of clay. The bulge of the clay layer is established for 215.9 mm bottomhole diameter. Functional correlation of pressure propagation through the layer of clay has been determined and a reaction of the top clay layer has been shown to have bulge with a height of 25 mm. A pressure distribution scheme (balance has been developed, which takes into account the distance from layers with abnormal pressure to the bottomhole. A balance equation for reservoir pressure evaluation has been derived including well depth, distance from bottomhole to the top of the formation with abnormal pressure and density of clay.

  19. Exhibiting the Human/Exhibiting the Cyborg: “Who Am I?”

    Directory of Open Access Journals (Sweden)

    Sophia C. Vackimes

    2013-08-01

    Full Text Available The role of the museum in shaping our relationship to science and technology, particularly cyborgization, is illuminated by a close examination of the Who Am I permanent exhibition in the Wellcome Wing of the Science Museum of London. This innovative exhibition raises real questions both about the human-technology-science relationship but also about museography. In the context of the history and current practices of museums engaging contemporary technological developments the evidence suggest that even as the Who am I? exhibit did break somewhat from previous approaches, especially the didactic presentation of the socially useful, it has not changed the feld as a whole.

  20. Structure and Filling Characteristics of Paleokarst Reservoirs in the Northern Tarim Basin, Revealed by Outcrop, Core and Borehole Images

    Directory of Open Access Journals (Sweden)

    Tian Fei

    2017-06-01

    Full Text Available The Ordovician paleokarst reservoirs in the Tahe oilfield, with burial depths of over 5300 m, experienced multiple phases of geologic processes and exhibit strong heterogeneity. Core testing can be used to analyse the characteristics of typical points at the centimetre scale, and seismic datasets can reveal the macroscopic outlines of reservoirs at the >10-m scale. However, neither method can identify caves, cave fills and fractures at the meter scale. Guided by outcrop investigations and calibrations based on core sample observations, this paper describes the interpretation of high longitudinal resolution borehole images, the identification of the characteristics of caves, cave fills (sedimentary, breccia and chemical fills and fractures in single wells, and the identification of structures and fill characteristics at the meter scale in the strongly heterogeneous paleokarst reservoirs. The paleogeomorphology, a major controlling factor in the distribution of paleokarst reservoirs, was also analysed. The results show that one well can penetrate multiple cave layers of various sizes and that the caves are filled with multiple types of fill. The paleogeomorphology can be divided into highlands, slopes and depressions, which controlled the structure and fill characteristics of the paleokarst reservoirs. The results of this study can provide fundamental meter-scale datasets for interpreting detailed geologic features of deeply buried paleocaves, can be used to connect core- and seismic-scale interpretations, and can provide support for the recognition and development of these strongly heterogeneous reservoirs.

  1. Reservoir Cathode for Electric Space Propulsion, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a hollow reservoir cathode to improve performance in ion and Hall thrusters. We will adapt our existing reservoir cathode technology to this purpose....

  2. Evaluation of Gaussian approximations for data assimilation in reservoir models

    KAUST Repository

    Iglesias, Marco A.; Law, Kody J H; Stuart, Andrew M.

    2013-01-01

    is fundamental for the optimal management of reservoirs. Unfortunately, due to the large-scale highly nonlinear properties of standard reservoir models, characterizing the posterior is computationally prohibitive. Instead, more affordable ad hoc techniques, based

  3. Performance Analysis of Depleted Oil Reservoirs for Underground Gas Storage

    Directory of Open Access Journals (Sweden)

    Dr. C.I.C. Anyadiegwu

    2014-02-01

    Full Text Available The performance of underground gas storage in depleted oil reservoir was analysed with reservoir Y-19, a depleted oil reservoir in Southern region of the Niger Delta. Information on the geologic and production history of the reservoir were obtained from the available field data of the reservoir. The verification of inventory was done to establish the storage capacity of the reservoir. The plot of the well flowing pressure (Pwf against the flow rate (Q, gives the deliverability of the reservoir at various pressures. Results of the estimated properties signified that reservoir Y-19 is a good candidate due to its storage capacity and its flow rate (Q of 287.61 MMscf/d at a flowing pressure of 3900 psig

  4. AUTOMATED TECHNIQUE FOR FLOW MEASUREMENTS FROM MARIOTTE RESERVOIRS.

    Science.gov (United States)

    Constantz, Jim; Murphy, Fred

    1987-01-01

    The mariotte reservoir supplies water at a constant hydraulic pressure by self-regulation of its internal gas pressure. Automated outflow measurements from mariotte reservoirs are generally difficult because of the reservoir's self-regulation mechanism. This paper describes an automated flow meter specifically designed for use with mariotte reservoirs. The flow meter monitors changes in the mariotte reservoir's gas pressure during outflow to determine changes in the reservoir's water level. The flow measurement is performed by attaching a pressure transducer to the top of a mariotte reservoir and monitoring gas pressure changes during outflow with a programmable data logger. The advantages of the new automated flow measurement techniques include: (i) the ability to rapidly record a large range of fluxes without restricting outflow, and (ii) the ability to accurately average the pulsing flow, which commonly occurs during outflow from the mariotte reservoir.

  5. Increasing Waterflood Reserves in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, D.; Koerner, R.; Moos D.; Nguyen, J.; Phillips, C.; Tagbor, K.; Walker, S.

    1999-04-05

    This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate.

  6. Quantification of a maximum injection volume of CO2 to avert geomechanical perturbations using a compositional fluid flow reservoir simulator

    Science.gov (United States)

    Jung, Hojung; Singh, Gurpreet; Espinoza, D. Nicolas; Wheeler, Mary F.

    2018-02-01

    Subsurface CO2 injection and storage alters formation pressure. Changes of pore pressure may result in fault reactivation and hydraulic fracturing if the pressure exceeds the corresponding thresholds. Most simulation models predict such thresholds utilizing relatively homogeneous reservoir rock models and do not account for CO2 dissolution in the brine phase to calculate pore pressure evolution. This study presents an estimation of reservoir capacity in terms of allowable injection volume and rate utilizing the Frio CO2 injection site in the coast of the Gulf of Mexico as a case study. The work includes laboratory core testing, well-logging data analyses, and reservoir numerical simulation. We built a fine-scale reservoir model of the Frio pilot test in our in-house reservoir simulator IPARS (Integrated Parallel Accurate Reservoir Simulator). We first performed history matching of the pressure transient data of the Frio pilot test, and then used this history-matched reservoir model to investigate the effect of the CO2 dissolution into brine and predict the implications of larger CO2 injection volumes. Our simulation results -including CO2 dissolution- exhibited 33% lower pressure build-up relative to the simulation excluding dissolution. Capillary heterogeneity helps spread the CO2 plume and facilitate early breakthrough. Formation expansivity helps alleviate pore pressure build-up. Simulation results suggest that the injection schedule adopted during the actual pilot test very likely did not affect the mechanical integrity of the storage complex. Fault reactivation requires injection volumes of at least about sixty times larger than the actual injected volume at the same injection rate. Hydraulic fracturing necessitates much larger injection rates than the ones used in the Frio pilot test. Tested rock samples exhibit ductile deformation at in-situ effective stresses. Hence, we do not expect an increase of fault permeability in the Frio sand even in the presence of

  7. State of the art of reservoir sedimentation management in Spain

    OpenAIRE

    Avendaño Salas, Cándido; Sanz Montero, Esther; Cobo Rayán, Rafael

    2000-01-01

    Part of the total reservoir storage capacity in Spain (56 km3) is lost due to sedimentation processes taking place. Surveys carried out in 121 reservoirs indicate that 6% of them have undergone a capacity reduction of over 50%. However, most of them (81%) are characterised by a reservoir capacity loss below 20%. The most frequent methods used to control reservoir sedimentation in Spain fall into one of the following groups: reduction of sediment yield through basin management and removal of t...

  8. First assessment of the ecological status of Karaoun reservoir, Lebanon

    International Nuclear Information System (INIS)

    Fadel, A.; Lemaire, B.; Vinc on Leite, B.; Tassin, B.; Amacha, N.; Slim, K.; Atoui, A.

    2014-01-01

    Many reservoirs have been constructed throughout the world during the 20th century, with many also suffering from eutrophication. The resulting increased phytoplankton biomass in reservoirs impairs their use. Except for Lake Kinneret, the environmental status of lakes and reservoirs in the Middle East is poorly documented. Karaoun reservoir, also known as Qaroun, Qaraoun or Qarun, is the largest water body in Lebanon, having been constructed for irrigation and hydropower production. This present study reviews Karaoun reservoir, including its characteristics, uses, water quality and phytoplankton succession, to assess the environmental status of the reservoir on the basis of the few existing previous publications about the reservoir. Since 2004, which is 39 years after its construction, the reservoir is considered to be hypereutrophic, with low phytoplankton biodiversity and regular blooms of toxic cyanobacteria. The nutrient and trace metal concentrations would not prevent use of the reservoir for a drinking water supply for Beirut, as is currently being planned, although not all the micropollutants in the lake were documented. Karaoun reservoir is compared to other monitored lakes and reservoirs around the Mediterranean Sea. They share annual toxic cyanobacteria blooms of Aphanizomenon ovalisporum and of Microcystis aeruginosa. The phytoplankton composition and succession of Karaoun reservoir is more similar to El Gergal reservoir (Spain) than nearby natural lakes such as Lake Kinneret (Israel) and Lake Trichonis (Greece). Phytoplankton diversity in Karaoun reservoir was the lowest, due to higher nutrient concentrations and a larger decrease in water level in the dry season. Karaoun reservoir represents an interesting example of the potential response of the phytoplankton community in other lakes and reservoirs during the drought periods expected to occur as a result of global climate change. (author)

  9. Reservoir management under consideration of stratification and hydraulic phenomena

    OpenAIRE

    Nandalal, K.D.W.

    1995-01-01


    Reservoirs are the most important components in a water resources system. They are used to store water to extend its temporal availability. The physical, chemical and biological characteristics of water change when impounded in reservoirs. This implies the possibility of using reservoirs for the control of the quality of water besides merely satisfying the quantity requirement. This study presents several techniques formulated to manage a reservoir when both quantity and quality of...

  10. Sudden water pollution accidents and reservoir emergency operations: impact analysis at Danjiangkou Reservoir.

    Science.gov (United States)

    Zheng, Hezhen; Lei, Xiaohui; Shang, Yizi; Duan, Yang; Kong, Lingzhong; Jiang, Yunzhong; Wang, Hao

    2018-03-01

    Danjiangkou Reservoir is the source reservoir of the Middle Route of the South-to-North Water Diversion Project (MRP). Any sudden water pollution accident in the reservoir would threaten the water supply of the MRP. We established a 3-D hydrodynamic and water quality model for the Danjiangkou Reservoir, and proposed scientific suggestions on the prevention and emergency management for sudden water pollution accidents based on simulated results. Simulations were performed on 20 hypothetical pollutant discharge locations and 3 assumed amounts, in order to model the effect of pollutant spreading under different reservoir operation types. The results showed that both the location and mass of pollution affected water quality; however, different reservoir operation types had little effect. Five joint regulation scenarios, which altered the hydrodynamic processes of water conveyance for the Danjiangkou and Taocha dams, were considered for controlling pollution dispersion. The results showed that the spread of a pollutant could be effectively controlled through the joint regulation of the two dams and that the collaborative operation of the Danjiangkou and Taocha dams is critical for ensuring the security of water quality along the MRP.

  11. Shape-Memory PVDF Exhibiting Switchable Piezoelectricity.

    Science.gov (United States)

    Hoeher, Robin; Raidt, Thomas; Novak, Nikola; Katzenberg, Frank; Tiller, Joerg C

    2015-12-01

    In this study, a material is designed which combines the properties of shape-memory and electroactive polymers. This is achieved by covalent cross-linking of polyvinylidene fluoride. The resulting polymer network exhibits excellent shape-memory properties with a storable strain of 200%, and fixity as well as recovery values of 100%. Programming upon rolling induces the transformation from the nonelectroactive α-phase to the piezoelectric β-phase. The highest β-phase content is found to be 83% for a programming strain of 200% affording a d33 value of -30 pm V(-1). This is in good accordance with literature known values for piezoelectric properties. Thermal triggering this material does not only result in a shape change but also renders the material nonelectroactive. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Applied Gamification in Self-guided Exhibitions

    DEFF Research Database (Denmark)

    Vistisen, Peter; Selvadurai, Vashanth; Krishnasamy, Rameshnath Kala

    2018-01-01

    This paper contributes to the current understanding of applied digital gamification by providing insights from two design cases from the Danish aqua zoo, the North Sea Oceanarium, concerned with self-facilitated exhibitions. Grounded in a short review of the current state of art, we provide two...... empirical case examples, concerning a mobile augmented reality design and an Instagram service. Analyzing the design process behind these cases, we identify some of the challenges arising from applying gamification in practice, and whether these insights verify, extents or contradicts current examples...... of applied gamification research. Specifically, the cases provide insights to the challenge of on-boarding visitors into participating and using the designed products during their visit. In both cases, providing certain incentives for using the app or participating in the Instagram challenge, seemed...

  13. Exhibiting health and medicine as culture

    DEFF Research Database (Denmark)

    Whiteley, Louise; Tybjerg, Karin; Pedersen, Bente Vinge

    2017-01-01

    -being of their visitors, we instead focus on how museums should communicate about health and medicine. Methods: The paper describes three examples of exhibitions at Medical Museion that attempt to display medicine as culture, and draws out three of the key strategies they employ. Results: The three key strategies are: (1......Introduction: This paper discusses the potential role of medical museums in public engagement with health and medicine, based on the work of Medical Museion at the University of Copenhagen. Rather than asking whether cultural venues such as museums can directly improve the well......: There is increasing emphasis on the need for health communication to recognize people’s multiple, lived cultures. We argue that we should also recognize that medical research and practice is itself a form of culture, and as such is multiple and historically shifting. This paper demonstrates that museums are an ideal...

  14. The coordination office at SIREME 2008 exhibition

    International Nuclear Information System (INIS)

    Grotz, Claudia; Cassin, Fabrice; Evrard, Aurelien; Froeding, Veronique; Galaup, Serge; Kaelble, Laure; Persem, Melanie; Regnier, Yannick; )

    2008-01-01

    The French-German office for Renewable energies (OFAEnR) organised several presentations at the occasion of the SIREME International exhibition of renewable energies and energy management. This document brings together these presentations (slides) dealing with: 1 - The new German Renewable Energy Sources Act (EEG) and its impact on wind energy (Claudia Grotz); 2 - Consequences of the July 10, 2006 wind energy tariff bylaw cancelling (Fabrice Cassin); 3 - Wind energy trajectory in France and Germany: a political perspective (Aurelien Evrard); 4 - The wind energy development areas (Veronique Froeding); 5 - A commitment at the heart of our business: renewable energy sources (Serge Galaup); 6 - The wind energy coordination office (Laure Kaelble); 7 - New challenges of the German wind energy market (Melanie Persem); 8 - An industry - a qualification standard (Yannick Regnier)

  15. The Road Transport world exhibition in Paris

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    Following the agreement between French and German professionals of automobile and industrial vehicle, the Road Transport world exhibition will take place alternatively in Paris and Hanover. The 1995 meeting has taken place in Paris (September 15-21) and about 20 countries were represented. Road transport is the principal way of goods transportation in France and represent 88% of the traffic explained in tons gross and 70% in tons km. The petroleum dependence of the transportation sector is becoming a worrying problem as the gasoline and diesel fuels taxes will be discussed in the 1996 financial laws project. According to the last ''Worldwide energetic perspectives'' report published by the IEA, in 2010 the transportation sector could absorb more than 60% of the worldwide petroleum consumption. This increase represents a challenge to the petroleum industry to increase the energetic efficiency of the vehicle fuels and the production of diesel fuels, and conversely to reduce the pollution effluents. (J.S.). 4 tabs

  16. Application of an imaging system to a museum exhibition for developing interactive exhibitions

    Science.gov (United States)

    Miyata, Kimiyoshi; Inoue, Yuka; Takiguchi, Takahiro; Tsumura, Norimichi; Nakaguchi, Toshiya; Miyake, Yoichi

    2009-10-01

    In the National Museum of Japanese History, 215,759 artifacts are stored and used for research and exhibitions. In museums, due to the limitation of space in the galleries, a guidance system is required to satisfy visitors' needs and to enhance their understanding of the artifacts. We introduce one exhibition using imaging technology to improve visitors' understanding of a kimono (traditional Japanese clothing) exhibition. In the imaging technology introduced, one data projector, one display with touch panel interface, and magnifiers were used as exhibition tools together with a real kimono. The validity of this exhibition method was confirmed by results from a visitors' interview survey. Second, to further develop the interactive guidance system, an augmented reality system that consisted of cooperation between the projector and a digital video camera was also examined. A white paper board in the observer's hand was used as a projection screen and also as an interface to control the images projected on the board. The basic performance of the proposed system was confirmed; however continuous development was necessary for applying the system to actual exhibitions.

  17. Mathematical and field analysis of longitudinal reservoir infill

    Science.gov (United States)

    Ke, W. T.; Capart, H.

    2016-12-01

    In reservoirs, severe problems are caused by infilled sediment deposits. In long term, the sediment accumulation reduces the capacity of reservoir storage and flood control benefits. In the short term, the sediment deposits influence the intakes of water-supply and hydroelectricity generation. For the management of reservoir, it is important to understand the deposition process and then to predict the sedimentation in reservoir. To investigate the behaviors of sediment deposits, we propose a one-dimensional simplified theory derived by the Exner equation to predict the longitudinal sedimentation distribution in idealized reservoirs. The theory models the reservoir infill geomorphic actions for three scenarios: delta progradation, near-dam bottom deposition, and final infill. These yield three kinds of self-similar analytical solutions for the reservoir bed profiles, under different boundary conditions. Three analytical solutions are composed by error function, complementary error function, and imaginary error function, respectively. The theory is also computed by finite volume method to test the analytical solutions. The theoretical and numerical predictions are in good agreement with one-dimensional small-scale laboratory experiment. As the theory is simple to apply with analytical solutions and numerical computation, we propose some applications to simulate the long-profile evolution of field reservoirs and focus on the infill sediment deposit volume resulting the uplift of near-dam bottom elevation. These field reservoirs introduced here are Wushe Reservoir, Tsengwen Reservoir, Mudan Reservoir in Taiwan, Lago Dos Bocas in Puerto Rico, and Sakuma Dam in Japan.

  18. 33 CFR 110.77 - Amistad Reservoir, Tex.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Amistad Reservoir, Tex. 110.77... ANCHORAGE REGULATIONS Special Anchorage Areas § 110.77 Amistad Reservoir, Tex. (a) Diablo East, Tex. That portion of the Amistad Reservoir enclosed by a line connecting the following points, excluding a 300-foot...

  19. Analysis of Fluvial Sediment Discharges into Kubanni Reservoir ...

    African Journals Online (AJOL)

    The sediment discharges into the Kubanni Reservoir (KR) has been measured and analysed in this study. The predominant sandy-clay sediment in the reservoir has an estimated total sediment load of 20,387,000 kg/year. The depth and area coverage of the reservoir was surveyed using a defined distributed grid line ...

  20. Reservoir site evaluation through routing | Ogunlela | Journal of ...

    African Journals Online (AJOL)

    ... m3/s, and a relative attenuation of 41.10%. Also; the reservoir would not be overtopped since the 99.54 m water elevation for the 25-yr, 24-hr storm was below the reservoir embankment top elevation. Keywords:Reservoir routing. Journal of Modeling, Design and Management of Engineering Systems Vol. 3 (1) 2005: pp.

  1. Reservoir management under consideration of stratification and hydraulic phenomena

    NARCIS (Netherlands)

    Nandalal, K.D.W.

    1995-01-01


    Reservoirs are the most important components in a water resources system. They are used to store water to extend its temporal availability. The physical, chemical and biological characteristics of water change when impounded in reservoirs. This implies the possibility of using reservoirs

  2. Factors affecting reservoir and stream-water quality in the Cambridge, Massachusetts, drinking-water source area and implications for source-water protection

    Science.gov (United States)

    Waldron, Marcus C.; Bent, Gardner C.

    2001-01-01

    This report presents the results of a study conducted by the U.S. Geological Survey, in cooperation with the city of Cambridge, Massachusetts, Water Department, to assess reservoir and tributary-stream quality in the Cambridge drinking-water source area, and to use the information gained to help guide the design of a comprehensive water-quality monitoring program for the source area. Assessments of the quality and trophic state of the three primary storage reservoirs, Hobbs Brook Reservoir, Stony Brook Reservoir, and Fresh Pond, were conducted (September 1997-November 1998) to provide baseline information on the state of these resources and to determine the vulnerability of the reservoirs to increased loads of nutrients and other contaminants. The effects of land use, land cover, and other drainage-basin characteristics on sources, transport, and fate of fecal-indicator bacteria, highway deicing chemicals, nutrients, selected metals, and naturally occurring organic compounds in 11 subbasins that contribute water to the reservoirs also was investigated, and the data used to select sampling stations for incorporation into a water-quality monitoring network for the source area. All three reservoirs exhibited thermal and chemical stratification, despite artificial mixing by air hoses in Stony Brook Reservoir and Fresh Pond. The stratification produced anoxic or hypoxic conditions in the deepest parts of the reservoirs and these conditions resulted in the release of ammonia nitrogen orthophosphate phosphorus, and dissolved iron and manganese from the reservoir bed sediments. Concentrations of sodium and chloride in the reservoirs usually were higher than the amounts recommended by the U.S. Environmental Protection agency for drinking-water sources (20 milligrams per liter for sodium and 250 milligrams per liter for chloride). Maximum measured sodium concentrations were highest in Hobbs Brook Reservoir (113 milligrams per liter), intermediate in Stony Brook Reservoir (62

  3. Third workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P. (eds.)

    1977-12-15

    The Third Workshop on Geothermal Reservoir Engineering convened at Stanford University on December 14, 1977, with 104 attendees from six nations. In keeping with the recommendations expressed by the participants at the Second Workshop, the format of the Workshop was retained, with three days of technical sessions devoted to reservoir physics, well and reservoir testing, field development, and mathematical modeling of geothermal reservoirs. The program presented 33 technical papers, summaries of which are included in these Proceedings. Although the format of the Workshop has remained constant, it is clear from a perusal of the Table of Contents that considerable advances have occurred in all phases of geothermal reservoir engineering over the past three years. Greater understanding of reservoir physics and mathematical representations of vapor-dominated and liquid-dominated reservoirs are evident; new techniques for their analysis are being developed, and significant field data from a number of newer reservoirs are analyzed. The objectives of these workshops have been to bring together researchers active in the various physical and mathematical disciplines comprising the field of geothermal reservoir engineering, to give the participants a forum for review of progress and exchange of new ideas in this rapidly developing field, and to summarize the effective state of the art of geothermal reservoir engineering in a form readily useful to the many government and private agencies involved in the development of geothermal energy. To these objectives, the Third Workshop and these Proceedings have been successfully directed. Several important events in this field have occurred since the Second Workshop in December 1976. The first among these was the incorporation of the Energy Research and Development Administration (ERDA) into the newly formed Department of Energy (DOE) which continues as the leading Federal agency in geothermal reservoir engineering research. The Third

  4. Diagenetic Evolution and Reservoir Quality of Sandstones in the North Alpine Foreland Basin: A Microscale Approach.

    Science.gov (United States)

    Gross, Doris; Grundtner, Marie-Louise; Misch, David; Riedl, Martin; Sachsenhofer, Reinhard F; Scheucher, Lorenz

    2015-10-01

    Siliciclastic reservoir rocks of the North Alpine Foreland Basin were studied focusing on investigations of pore fillings. Conventional oil and gas production requires certain thresholds of porosity and permeability. These parameters are controlled by the size and shape of grains and diagenetic processes like compaction, dissolution, and precipitation of mineral phases. In an attempt to estimate the impact of these factors, conventional microscopy, high resolution scanning electron microscopy, and wavelength dispersive element mapping were applied. Rock types were established accordingly, considering Poro/Perm data. Reservoir properties in shallow marine Cenomanian sandstones are mainly controlled by the degree of diagenetic calcite precipitation, Turonian rocks are characterized by reduced permeability, even for weakly cemented layers, due to higher matrix content as a result of lower depositional energy. Eocene subarkoses tend to be coarse-grained with minor matrix content as a result of their fluvio-deltaic and coastal deposition. Reservoir quality is therefore controlled by diagenetic clay and minor calcite cementation.Although Eocene rocks are often matrix free, occasionally a clay mineral matrix may be present and influence cementation of pores during early diagenesis. Oligo-/Miocene deep marine rocks exhibit excellent quality in cases when early cement is dissolved and not replaced by secondary calcite, mainly bound to the gas-water contact within hydrocarbon reservoirs.

  5. Phytoplankton species diversity indices in Anjanapura reservoir, Western Ghat region, India.

    Science.gov (United States)

    Basavaraja, D; Narayana, J; Puttaiah, E T; Prakash, K

    2013-07-01

    A qualitative study on species composition and diversity of phytoplankton flora was carried out in the Anjanapura reservoir. Water samples were collected monthly at four sites from November 2005 to October 2007 for plankton analysis. A total of 152 phytoplankton species belonging to 59 genera were recorded. The species belonging to genera Crucigenia, Pediastrum, Scenedesmus, Tetraedron, Cyclotella, Gyrosigma, Melosira, Navicula, Fragillaria, pinnularia, Synedra, Closterium, Cosmarium, Euastrum, Staurastrum, Gleocapsa, Merismopedia, Microcystis, Oscillatoria, Euglena and Phacus were found dominant. Phytoplankton density was recorded in the range of 222-1467 Org l(-1) for chlorococcales, 267-1467 Org I (-1) for diatoms, 44-889 Org l(-1) for desmids, 44-889 Org l(-1) for blue-greens and 22-1667 Org l(-1) for euglenoids. Seasonal density Shannon-Weiner diversity index (1.60-1.88) indicate that reservoir exhibited rich phytoplankton and Nygaard tropic status indices for myxophycean (1.0-1.50), chlorophycean (1.62-2.16), diatoms (0.10-0.14), euglenophycean (0.18-0.19) and compound quotient(3.25-4.66) showed that reservoir was moderately polluted. From the observed data, it could be concluded that the presence of more diverse group of phytoplankton indicate the productivity of the reservoir.

  6. Dynamics of Total Microcystin LR Concentration in Three Subtropical Hydroelectric Generation Reservoirs in Uruguay, South America.

    Science.gov (United States)

    González-Piana, Mauricio; Fabián, Daniel; Piccardo, Andrea; Chalar, Guillermo

    2017-10-01

    This study analyzed the temporal dynamics of total microcystin LR concentrations between the years of 2012 and 2015 in the Bonete, Baygorria and Palmar hydroelectric generation reservoirs in the central region of the Negro River, Uruguay. The three reservoirs showed differents total microcystin LR concentration, with no significant differences among them. Over 20 sampling dates, the three reservoirs exhibited total microcystin LR concentrations on eight occasions that corresponded to a slight to moderate human health risk according to WHO guideline values for recreational waters. By determining the concentration of microcystin LR in cyanobacterial biomass, we identified cyanobacterial populations that occurred over time with varying degrees of toxin production (maximal 85.4 µg/mm 3 ). The microcystin LR concentration in Bonete was positively correlated with temperature (r = 0.587) and cyanobacterial biomass (r = 0.736), in Baygorria with cyanobacterial biomass (r = 0.521), and in Palmar with temperature (r = 0.500) and negatively correlated with ammonia (r = -0.492). Action is needed to reduce the presence of toxic cyanobacteria in these systems. A decrease in the use of agrochemicals and management changes in the reservoir basins could be successful long-term measures.

  7. Deposition behavior, risk assessment and source identification of heavy metals in reservoir sediments of Northeast China.

    Science.gov (United States)

    Zhu, Lin; Liu, Jianwei; Xu, Shiguo; Xie, Zaigang

    2017-08-01

    Sediment cores from five reservoirs, located in the Liaoning and Jilin Provinces in Northeast China, were collected to investigate the accumulation and potential toxicity of heavy metals (Fe, Mn, Cu, Cd, Pb, Zn, and Cr) during a sampling campaign in February, 2015. The results showed that all the detected metals accumulated significantly, especially Cd, compared to their respective background values. Among these reservoirs, Biliuhe Reservoir had markedly increasing trends for organic matter and all the metals, among which Mn was elevated by 280% to 3411mg/kg in a core of only 18cm in depth. Xinlicheng Reservoir was characterized by heavy siltation and varying metal distribution due to its regular geometric features and pulsed flood events. The Enrichment factor (EF) and geo-accumulation index (I geo ) indicated Cd was strongly enriched by anthropogenic inputs, with the values of EF and I geo greater than 8 and 3, respectively. The toxicity assessment calculated using consensus-based sediment quality guidelines (SQGs) implied the whole cores of Tanghe and Dahuofang and the upper cores of Biliuhe, Xinlicheng and Fengman exhibited toxicity to sediment-dwelling organisms. Cr contributed more to Q m-PEC than the other heavy metals, because only Cr exceeded the probable effect concentration (PEC) despite its low enrichment. According to the results of correlation analysis (CA) and principal components analysis (PCA), mining industries and agricultural activities within the basin were the main anthropogenic pollution sources for these heavy metals. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Incorporating Scale-Dependent Fracture Stiffness for Improved Reservoir Performance Prediction

    Science.gov (United States)

    Crawford, B. R.; Tsenn, M. C.; Homburg, J. M.; Stehle, R. C.; Freysteinson, J. A.; Reese, W. C.

    2017-12-01

    We present a novel technique for predicting dynamic fracture network response to production-driven changes in effective stress, with the potential for optimizing depletion planning and improving recovery prediction in stress-sensitive naturally fractured reservoirs. A key component of the method involves laboratory geomechanics testing of single fractures in order to develop a unique scaling relationship between fracture normal stiffness and initial mechanical aperture. Details of the workflow are as follows: tensile, opening mode fractures are created in a variety of low matrix permeability rocks with initial, unstressed apertures in the micrometer to millimeter range, as determined from image analyses of X-ray CT scans; subsequent hydrostatic compression of these fractured samples with synchronous radial strain and flow measurement indicates that both mechanical and hydraulic aperture reduction varies linearly with the natural logarithm of effective normal stress; these stress-sensitive single-fracture laboratory observations are then upscaled to networks with fracture populations displaying frequency-length and length-aperture scaling laws commonly exhibited by natural fracture arrays; functional relationships between reservoir pressure reduction and fracture network porosity, compressibility and directional permeabilities as generated by such discrete fracture network modeling are then exported to the reservoir simulator for improved naturally fractured reservoir performance prediction.

  9. Detailed geologic modeling of a turbidity reservoir interval at the Mars discovery

    Energy Technology Data Exchange (ETDEWEB)

    Mahaffie, M.J.; Chapin, M.A. [Shell Exploration and Production Technology Co. (United States); Henry, W.A. [Shell Offshore, Inc. (United States)

    1995-12-31

    Detailed reservoir architecture studies using high resolution seismic data coupled with geologic and seismic inversion modeling have been used to evaluate a major hydrocarbon bearing turbidite reservoir found within Prospect Mars. Early interpretations of this interval, based on lower frequency (40 Hz) seismic data, indicated the presence of a single, laterally continuous event covering an area nearly 3 miles square ({approx} 5200 acres). Correlations from well control supported the notion that this seismic event comprised a series of continuous sheet sands exhibiting a high degree of lateral continuity and connectivity. However pressure data taken during fluid sampling of the reservoir suggested the possibility of discontinuities not observed within the resolution of the seismic data. Seismic reprocessing enhancements to increase frequency content revealed the presence of multiple stratigraphic features not previously recognized. Detailed seismic mapping using loop-level seismic attributes and seismic inversion studies constrained by geologic models provide a more realistic depiction of the environment of deposition and improve reservoir simulation modeling for this stratigraphic interval. (author). 3 figs

  10. An Intelligent Systems Approach to Reservoir Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shahab D. Mohaghegh; Jaime Toro; Thomas H. Wilson; Emre Artun; Alejandro Sanchez; Sandeep Pyakurel

    2005-08-01

    Today, the major challenge in reservoir characterization is integrating data coming from different sources in varying scales, in order to obtain an accurate and high-resolution reservoir model. The role of seismic data in this integration is often limited to providing a structural model for the reservoir. Its relatively low resolution usually limits its further use. However, its areal coverage and availability suggest that it has the potential of providing valuable data for more detailed reservoir characterization studies through the process of seismic inversion. In this paper, a novel intelligent seismic inversion methodology is presented to achieve a desirable correlation between relatively low-frequency seismic signals, and the much higher frequency wireline-log data. Vertical seismic profile (VSP) is used as an intermediate step between the well logs and the surface seismic. A synthetic seismic model is developed by using real data and seismic interpretation. In the example presented here, the model represents the Atoka and Morrow formations, and the overlying Pennsylvanian sequence of the Buffalo Valley Field in New Mexico. Generalized regression neural network (GRNN) is used to build two independent correlation models between; (1) Surface seismic and VSP, (2) VSP and well logs. After generating virtual VSP's from the surface seismic, well logs are predicted by using the correlation between VSP and well logs. The values of the density log, which is a surrogate for reservoir porosity, are predicted for each seismic trace through the seismic line with a classification approach having a correlation coefficient of 0.81. The same methodology is then applied to real data taken from the Buffalo Valley Field, to predict inter-well gamma ray and neutron porosity logs through the seismic line of interest. The same procedure can be applied to a complete 3D seismic block to obtain 3D distributions of reservoir properties with less uncertainty than the geostatistical

  11. Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf Carbonate Reservoir

    International Nuclear Information System (INIS)

    Hickman, Scott T.; Justice James L.; Taylor, Archie R.

    1999-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs

  12. Modeling Reservoir-River Networks in Support of Optimizing Seasonal-Scale Reservoir Operations

    Science.gov (United States)

    Villa, D. L.; Lowry, T. S.; Bier, A.; Barco, J.; Sun, A.

    2011-12-01

    HydroSCOPE (Hydropower Seasonal Concurrent Optimization of Power and the Environment) is a seasonal time-scale tool for scenario analysis and optimization of reservoir-river networks. Developed in MATLAB, HydroSCOPE is an object-oriented model that simulates basin-scale dynamics with an objective of optimizing reservoir operations to maximize revenue from power generation, reliability in the water supply, environmental performance, and flood control. HydroSCOPE is part of a larger toolset that is being developed through a Department of Energy multi-laboratory project. This project's goal is to provide conventional hydropower decision makers with better information to execute their day-ahead and seasonal operations and planning activities by integrating water balance and operational dynamics across a wide range of spatial and temporal scales. This presentation details the modeling approach and functionality of HydroSCOPE. HydroSCOPE consists of a river-reservoir network model and an optimization routine. The river-reservoir network model simulates the heat and water balance of river-reservoir networks for time-scales up to one year. The optimization routine software, DAKOTA (Design Analysis Kit for Optimization and Terascale Applications - dakota.sandia.gov), is seamlessly linked to the network model and is used to optimize daily volumetric releases from the reservoirs to best meet a set of user-defined constraints, such as maximizing revenue while minimizing environmental violations. The network model uses 1-D approximations for both the reservoirs and river reaches and is able to account for surface and sediment heat exchange as well as ice dynamics for both models. The reservoir model also accounts for inflow, density, and withdrawal zone mixing, and diffusive heat exchange. Routing for the river reaches is accomplished using a modified Muskingum-Cunge approach that automatically calculates the internal timestep and sub-reach lengths to match the conditions of

  13. Conformational and spectroscopic study of xanthogen ethyl formates, ROC(S)SC(O)OCH2CH3. Isolation of CH3CH2OC(O)SH

    Science.gov (United States)

    Juncal, Luciana C.; Cozzarín, Melina V.; Romano, Rosana M.

    2015-03-01

    ROC(S)SC(O)OCH2CH3, with R = CH3sbnd , (CH3)2CHsbnd and CH3(CH2)2sbnd , were obtained through the reaction between potassium xanthate salts, ROC(S)SK, and ethyl chloroformate, ClC(O)OCH2CH3. The liquid compounds were identified and characterized by 1H and 13C NMR and mass spectrometry. The conformations adopted by the molecules were studied by DFT methods. 6 conformers were theoretically predicted for R = CH3sbnd and (CH3)2CHsbnd , while the conformational flexibility of the n-propyl substituent increases the total number of feasible rotamers to 21. For the three molecules, the conformers can be associated in 3 groups, being the most stable the AS forms - the Cdbnd S double bond anti (A) with respect to the Csbnd S single bond and the Ssbnd C single bond syn (S) with respect to the Cdbnd O double bond - followed by AA and SS conformers. The vibrational spectra were interpreted in terms of the predicted conformational equilibrium, presenting the ν(Cdbnd O) spectral region signals corresponding to the three groups of conformers. A moderated pre-resonance Raman enhancement of the ν(Cdbnd S) vibrational mode of CH3(CH2)2OC(S)SC(O)OCH2CH3 was detected, when the excitation radiation approaches the energy of a n → π∗ electronic transition associated with the Cdbnd S chromophore. UV-visible spectra in different solvents were measured and interpreted in terms of TD-DFT calculations. The unknown molecule CH3CH2OC(O)SH was isolated by the UV-visible photolysis of CH3OC(S)SC(O)OCH2CH3 isolated in Ar matrix, and also obtained as a side-product of the reaction between potassium xanthate salts, ROC(S)SK, and ethyl chloroformate, ClC(O)OCH2CH3.

  14. Conformational and spectroscopic study of xanthogen ethyl formates, ROC(S)SC(O)OCH₂CH₃. Isolation of CH₃CH₂OC(O)SH.

    Science.gov (United States)

    Juncal, Luciana C; Cozzarín, Melina V; Romano, Rosana M

    2015-03-15

    ROC(S)SC(O)OCH2CH3, with R=CH3-, (CH3)2CH- and CH3(CH2)2-, were obtained through the reaction between potassium xanthate salts, ROC(S)SK, and ethyl chloroformate, ClC(O)OCH2CH3. The liquid compounds were identified and characterized by (1)H and (13)C NMR and mass spectrometry. The conformations adopted by the molecules were studied by DFT methods. 6 conformers were theoretically predicted for R=CH3- and (CH3)2CH-, while the conformational flexibility of the n-propyl substituent increases the total number of feasible rotamers to 21. For the three molecules, the conformers can be associated in 3 groups, being the most stable the AS forms - the C=S double bond anti (A) with respect to the C-S single bond and the S-C single bond syn (S) with respect to the C=O double bond - followed by AA and SS conformers. The vibrational spectra were interpreted in terms of the predicted conformational equilibrium, presenting the ν(C=O) spectral region signals corresponding to the three groups of conformers. A moderated pre-resonance Raman enhancement of the ν(C=S) vibrational mode of CH3(CH2)2OC(S)SC(O)OCH2CH3 was detected, when the excitation radiation approaches the energy of a n→π∗ electronic transition associated with the C=S chromophore. UV-visible spectra in different solvents were measured and interpreted in terms of TD-DFT calculations. The unknown molecule CH3CH2OC(O)SH was isolated by the UV-visible photolysis of CH3OC(S)SC(O)OCH2CH3 isolated in Ar matrix, and also obtained as a side-product of the reaction between potassium xanthate salts, ROC(S)SK, and ethyl chloroformate, ClC(O)OCH2CH3. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Maqalika Reservoir: utilisation and sustainability of Maqalika Reservoir as a source of potable water supply for Maseru in Lesotho

    CSIR Research Space (South Africa)

    Letsie, M

    2008-07-01

    Full Text Available The storage of water in the Maqalika reservoir is gradually decreasing as sediment, carried by the natural catchment run-off, accumulates in the reservoir. Moreover, water pumped into the reservoir from the Caledon River (which is heavily sedimented...

  16. Exhibition of Stochastic Resonance in Vestibular Perception

    Science.gov (United States)

    Galvan-Garza, R. C.; Clark, T. K.; Merfeld, D. M.; Bloomberg, J. J.; Oman, C. M.; Mulavara, A. P.

    2016-01-01

    Astronauts experience sensorimotor changes during spaceflight, particularly during G-transitions. Post flight sensorimotor changes include spatial disorientation, along with postural and gait instability that may degrade operational capabilities of the astronauts and endanger the crew. A sensorimotor countermeasure that mitigates these effects would improve crewmember safety and decrease risk. The goal of this research is to investigate the potential use of stochastic vestibular stimulation (SVS) as a technology to improve sensorimotor function. We hypothesize that low levels of SVS will improve sensorimotor perception through the phenomenon of stochastic resonance (SR), when the response of a nonlinear system to a weak input signal is enhanced by the application of a particular nonzero level of noise. This study aims to advance the development of SVS as a potential countermeasure by 1) demonstrating the exhibition of stochastic resonance in vestibular perception, a vital component of sensorimotor function, 2) investigating the repeatability of SR exhibition, and 3) determining the relative contribution of the semicircular canals (SCC) and otolith (OTO) organs to vestibular perceptual SR. A constant current stimulator was used to deliver bilateral bipolar SVS via electrodes placed on each of the mastoid processes, as previously done. Vestibular perceptual motion recognition thresholds were measured using a 6-degree of freedom MOOG platform and a 150 trial 3-down/1-up staircase procedure. In the first test session, we measured vestibular perceptual thresholds in upright roll-tilt at 0.2 Hz (SCC+OTO) with SVS ranging from 0-700 µA. In a second test session a week later, we re-measured roll-tilt thresholds with 0, optimal (from test session 1), and 1500 µA SVS levels. A subset of these subjects, plus naive subjects, participated in two additional test sessions in which we measured thresholds in supine roll-rotation at 0.2 Hz (SCC) and upright y-translation at 1 Hz

  17. Modeling reservoir geomechanics using discrete element method : Application to reservoir monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Alassi, Haitham Tayseer

    2008-09-15

    Understanding reservoir geomechanical behavior is becoming more and more important for the petroleum industry. Reservoir compaction, which may result in surface subsidence and fault reactivation, occurs during reservoir depletion. Stress changes and possible fracture development inside and outside a depleting reservoir can be monitored using time-lapse (so-called '4D') seismic and/or passive seismic, and this can give valuable information about the conditions of a given reservoir during production. In this study we will focus on using the (particle-based) Discrete Element Method (DEM) to model reservoir geomechanical behavior during depletion and fluid injection. We show in this study that DEM can be used in modeling reservoir geomechanical behavior by comparing results obtained from DEM to those obtained from analytical solutions. The match of the displacement field between DEM and the analytical solution is good, however there is mismatch of the stress field which is related to the way stress is measured in DEM. A good match is however obtained by measuring the stress field carefully. We also use DEM to model reservoir geomechanical behavior beyond the elasticity limit where fractures can develop and faults can reactivate. A general technique has been developed to relate DEM parameters to rock properties. This is necessary in order to use correct reservoir geomechanical properties during modeling. For any type of particle packing there is a limitation that the maximum ratio between P- and S-wave velocity Vp/Vs that can be modeled is 3 . The static behavior for a loose packing is different from the dynamic behavior. Empirical relations are needed for the static behavior based on numerical test observations. The dynamic behavior for both dense and loose packing can be given by analytical relations. Cosserat continuum theory is needed to derive relations for Vp and Vs. It is shown that by constraining the particle rotation, the S-wave velocity can be

  18. Reservoir simulation with MUFITS code: Extension for double porosity reservoirs and flows in horizontal wells

    Science.gov (United States)

    Afanasyev, Andrey

    2017-04-01

    Numerical modelling of multiphase flows in porous medium is necessary in many applications concerning subsurface utilization. An incomplete list of those applications includes oil and gas fields exploration, underground carbon dioxide storage and geothermal energy production. The numerical simulations are conducted using complicated computer programs called reservoir simulators. A robust simulator should include a wide range of modelling options covering various exploration techniques, rock and fluid properties, and geological settings. In this work we present a recent development of new options in MUFITS code [1]. The first option concerns modelling of multiphase flows in double-porosity double-permeability reservoirs. We describe internal representation of reservoir models in MUFITS, which are constructed as a 3D graph of grid blocks, pipe segments, interfaces, etc. In case of double porosity reservoir, two linked nodes of the graph correspond to a grid cell. We simulate the 6th SPE comparative problem [2] and a five-spot geothermal production problem to validate the option. The second option concerns modelling of flows in porous medium coupled with flows in horizontal wells that are represented in the 3D graph as a sequence of pipe segments linked with pipe junctions. The well completions link the pipe segments with reservoir. The hydraulics in the wellbore, i.e. the frictional pressure drop, is calculated in accordance with Haaland's formula. We validate the option against the 7th SPE comparative problem [3]. We acknowledge financial support by the Russian Foundation for Basic Research (project No RFBR-15-31-20585). References [1] Afanasyev, A. MUFITS Reservoir Simulation Software (www.mufits.imec.msu.ru). [2] Firoozabadi A. et al. Sixth SPE Comparative Solution Project: Dual-Porosity Simulators // J. Petrol. Tech. 1990. V.42. N.6. P.710-715. [3] Nghiem L., et al. Seventh SPE Comparative Solution Project: Modelling of Horizontal Wells in Reservoir Simulation

  19. Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Mella, Michael [Univ. of Utah, Salt Lake City, UT (United States). Energy and Geoscience Inst.

    2016-08-31

    The objective of this project was to develop and demonstrate an approach for tracking the evolution of circulation immediately following a hydraulic stimulation in an EGS reservoir. Series of high-resolution tracer tests using conservative and thermally reactive tracers were designed at recently created EGS reservoirs in order to track changes in fluid flow parameters such as reservoir pore volume, flow capacity, and effective reservoir temperature over time. Data obtained from the project would be available for the calibration of reservoir models that could serve to predict EGS performance following a hydraulic stimulation.

  20. Method of extracting heat from dry geothermal reservoirs

    Science.gov (United States)

    Potter, R.M.; Robinson, E.S.; Smith, M.C.

    1974-01-22

    Hydraulic fracturing is used to interconnect two or more holes that penetrate a previously dry geothermal reservoir, and to produce within the reservoir a sufficiently large heat-transfer surface so that heat can be extracted from the reservoir at a usefully high rate by a fluid entering it through one hole and leaving it through another. Introduction of a fluid into the reservoir to remove heat from it and establishment of natural (unpumped) convective circulation through the reservoir to accomplish continuous heat removal are important and novel features of the method. (auth)