bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting Compressor Valve Failures from Multi-Sensor Data
Authors: Patri Om Prasad , Reyna Nabor , Panangadan Anand , Prasanna Viktor 
Published: April 2015

Abstract
As the number of sensors deployed in the oilfield increases, there is a corresponding need to develop methods for fast, automated processing of large-scale sensor data streams. This problem is aggravated when the streams of sensor data are from multiple sensors with different characteristics and applicability to specific tasks of interest to the oilfield operator. Predictive analytics and data mining approaches have been proven to improve production efficiency, reduce downtime and identify safety hazards in real-world scenarios.
One of the most common failures in rotating equipment such as compressors is the breakdown of valves. This issue is of great value because a large proportion of production is dependent on rotating equipment. The aim of our undertaking is to find signature(s) in sensor data collected from compressors, which are predictive of valve failures. The first step towards achieving this is to rank the sensors themselves and use data from only those sensors that provide useful information. The resulting information can be used to prioritize and monitor maintenance schedules for compressors, which are often on remote platforms. The data used in our evaluation is from a large number of sensors that measure various physical properties of compressors, ranging from compressor vibrations and motor winding temperatures to pressure and temperature for both suction and discharge at the various compression stages.
We frame this failure prediction problem as a feature selection and time-series classification task. We use several evaluation methods for feature selection to identify the highly ranked sensors, and obtain insights about them. Once feature selection is complete, we propose to build a classifier based on time series shapelets. In particular, we adopt feature selection methods to automatically rank sensor streams in order of usefulness for the specific prediction tasks. Our results demonstrate that feature selection and time series approaches can be extended to handle multi-sensor Big Data streams from the oil and gas industry provided that accurate labeling of these datasets is possible.
Predicting Frac Stage Differential Stress and Microseismicity Using Geomechanical Modeling and Time Lapse Multi-Component Seismic - Application to the Montney Shale
Authors: Ouenes A. , Smaoui R. , Aimene Y. , Nairn J.A. 
Published: April 2015

Abstract
This paper describes the application of a workflow that uses Geophysics, Geology, and Geomechanics (3G) for completion optimization. The 3G workflow relies on the modeling of the interaction between hydraulic and natural fractures to estimate key reservoir properties that could be used to better understand data such as microseismicity or to plan an engineering completion. The 3G workflow uses geomechanical simulation that combines the meshless Material Point Method (MPM) with Continuous Fracture Modeling (CFM). The distribution of the natural fracture density is estimated from G&G data and in this paper it uses a time lapse 3C seismic that was processed for Shear Wave Velocity Anisotropy (SWVA). The geomechanical workflow uses this as an input to predict quickly over a large area the Normalized Differential Horizontal Stress (NDHS) and the Maximum Horizontal Stress Direction (MHSD) maps. Both these properties are used to improve the interpretation of microseismicity and to provide valuable information for the completion engineer to optimize his frac design. When using this approach on a Montney two wells pad, it appears that high values of NDHS are directly correlated to the fracture density estimated from the shear wave splitting parameter. While the local direction of maximum horizontal stress generally follows the direction of the imposed regional stress, large stress rotations of up to 90 degrees could occur in areas where the NDHS is very high. This observation is validated with microseismic data that confirms the local development of axial fracs instead of the desired transverse hydraulic fractures. Combining the NDHS and MHSD maps will be a very valuable completion optimization tool that would assist the completion engineer in adapting his frac design and treatment to the local geomechanical environment. The same 3G workflow will also provide to the completion engineer with quantitative tools such as the strain distribution and the J integral to predict or evaluate the efficiency of multiple fracing sequences and understand what is happening in the field experiments frequently showing zipper fracs outperforming other fracing sequences.
Completion Optimization Under Constraints - An Eagle Ford Shale Case Study
Authors: Okeahialam Ikenna , Yang Mei , Shinde Dnyaneshwar B , Sahai Vivek , Araque-Martinez Aura , Rai Rakesh 
Published: April 2015

Abstract
The Eagle Ford Shale (EFS) is the largest single economic development in the history of the state of Texas and ranks as the largest oil & gas development in the world based on capital invested. Between 2008 and the present, the EFS has become one of the most heavily drilled rock units in the United States and is the most active shale play in the world.
This paper presents a completion optimization framework for unconventional plays. The framework utilizes well production performance analysis to estimate the fracture characteristics and assists in diagnosing potential low productivity issues. The framework enables pre-completion planning, real time completion operations monitoring and post-completion evaluation to evaluate design effectiveness and optimize future design.
The key components of the framework are Prospectivity Analysis, Completions Optimization and Well Performance Analysis. Prospectivity analysis provides the map of Reservoir Quality (RQ) and Rock Quality (RkQ) across the play. Pre-completion planning, a component of Completions Optimization, is driven by Prospectivity Analysis with the goal to design the best completion based on the Rock Quality data available. During completions monitoring, the designs are updated based on actual field pump rates and quantities of proppant pumped to estimate actual hydraulic and propped fracture characteristics. The effective fracture geometry is determined based on well production calibration. Wellbore and completion problems could be diagnosed in this analysis, including damage of fractures, fluid behavior, and well interference.
We applied this framework to wells completed in the Eagle Ford Shale. The Reservoir Quality variability is based on petrophysical evaluation of logs acquired on all study wells. The characteristics of propped fractures were estimated based on geomechanical modeling of actual field pumping measurements. Even though the fractures extended above and below the target interval of Eagle Ford Shale, they were successful in creating the desired half-length from a design aspect. It was also observed that not all the clusters matured because of the stress shadow effect. The produced fluids in these wells ranged from black oil to gas condensate. Well interference was observed as a production penalty factor in well performance analysis. The behavior of current wells was used to design optimal completion for wells planned to be completed.
This framework utilizes common data sets collected by majority of operators. It provides intelligence for completion optimization of future wells after thorough investigation into fracture design, completion operation, and effective fracture characteristics. It is a systematic approach to optimized single well design as well as field development (multiple wells, pad drilling).
A Predictive Model for Improving the Efficiency of Frac Jobs
Authors: Korjani Mohammad M. , Mendel Jerry M. , Ershaghi Iraj 
Published: April 2015

Abstract
This paper presents a new method for forecasting post-fracturing responses in a tight oil reservoir using historical hydraulic fracturing data. The methodology is based on a nonlinear regression method called Variable Structure Regression (VSR). Data for 80 frac jobs were used to calibrate and predict responses. Information per fracturing job included feet of perforation, number of perforations per stage, number of stages, pad volume, slurry volume and sand volume. Information for a set of hydraulically fractured vertical wells was used to test the proposed technique.
The VSR method establishes the optimal nonlinear dependencies of variables to predict the cumulative liquid production after fracturing. This method determines the relationships between fracturing parameters and post-fracturing productions in the form of linguistic terms, thereby providing a physical understanding of the process. The exact mathematical structure of these linguistic terms and the number of terms are established simultaneously, thereby freeing the end user from time-consuming trial and error studies. Meanwhile, the knowledge of domain experts can be preserved as qualitative expert knowledge and may be combined with quantitative data.
A Monte Carlo simulation of 5-fold cross-validation method on fracture optimization data set shows the practical accuracy of the VSR model on forecasting post-fracturing performance. The VSR method achieved satisfactory prediction accuracy as well as statistical performance given the relatively small training data size and the complexity of the problem. The final result shows increase prediction accuracy for all the wells that outperforms other existing methods.
Analysis of Wellbore Failures and Re-Design of Slotted Liners for Horizontal Wells Applied in a Heavy Oilfield
Authors: Hallman T. , Yung V.Y.B. , Albertson A. 
Published: April 2015

Abstract
The Patos-Marinza Heavy Oil Field, located in Albania, was discovered in 1928. The field contains approximately 7.7 billion barrels of oil in place. The field consists of approximately 27 different sandstone formations. Over 2,700 wells have been drilled throughout the field and the cumulative oil production to date is more than 160 million barrels. Albania is a tectonically active region with earth quakes occurring regularly. Beginning in 2008 horizontal wells completed with slotted liners were drilled to redevelop the field. Starting in 2011 the wellbores started to fail with approximately 10% of the slotted liners failing per year severely impacting production performance. A review was undertaken to understand the cause of the wellbore failures from both a statistical analysis point of view including relating slotted liner failures to sand production, oil production, drilling practices and earth quakes. This paper presents the results of that review and summarizes the most likely failure mechanisms. The slotted liners were re-designed to limit sand production and to increase collapse strength to sustain the geo-mechanical forces associated with CHOPS production in an unconsolidated sand stone reservoir. The re-designed liner performed significantly better and a program was undertaken to re-drill the lateral sections of wells with failed liners. This paper details the liner design methodology, changes and the associated results.
Cross-cultural study on human-robot greeting interaction: acceptance and discomfort by Egyptians and Japanese
Authors: Trovato Gabriele , Zecca Massimiliano , Sessa Salvatore , Jamone Lorenzo , Ham Jaap , Hashimoto Kenji , Takanishi Atsuo 
Published: April 2015

AbstractAs witnessed in several behavioural studies, a complex relationship exists between people’s cultural background and their general acceptance towards robots. However, very few studies have investigated whether a robot’s original language and gesture based on certain culture have an impact on the people of the different cultures. The purpose of this work is to provide experimental evidence which supports the idea that humans may accept more easily a robot that can adapt to their specific culture. Indeed, improving acceptance and reducing discomfort is fundamental for future deployment of robots as assistive, health-care or companion devices into a society. We conducted a Human- Robot Interaction experiment both in Egypt and in Japan. Human subjects were engaged in a simulated video conference with robots that were greeting and speaking either in Arabic or in Japanese. The subjects completed a questionnaire assessing their preferences and their emotional state, while their spontaneous reactions were recorded in different ways. The results suggest that Egyptians prefer the Arabic robot, while they feel a sense of discomfort when interacting with the Japanese robot; the opposite is also true for the Japanese. These findings confirm the importance of the localisation of a robot in order to improve human acceptance during social human-robot interaction.
An Outlier Robust Filter for Maritime Robotics Applications
Authors: Indiveri Giovanni 
Published: April 2015

AbstractNavigation systems of autonomous vehicles often exploit range measurement information that may be affected by outliers. In marine application the presence of outliers in sonar bathymetry, for instance, can be particularly severe due to multipath phenomena in the acoustic propagation. This paper describes a possible approach to process range measurements highly contaminated by outliers. The proposed solution builds on a robust parameter identification algorithm minimizing a nonlinear cost function that exploits the mathematical properties of Gibbs entropy. Numerical examples on simulated data are provided to illustrate the method and its performance. The use of simulated data allows to vary the amount of noise and outliers contamination while knowing the ground truth values of the parameters to be identified. For the sake of experimental validation, the method is also applied to third party (publicly available) upward looking sonar ice draft data collected by submarines in the Arctic Ocean.
Attitudes towards service robots in domestic environments: The role of personality characteristics, individual interests, and demographic variables
Authors: Reich Natalia , Eyssel Friederike 
Published: April 2015

AbstractThe majority of EU citizens report a positive view about robots in general according to recent EU-level survey data. However, does this also hold true for attitudes towards service robots in particular? To investigate this research question, we conducted a survey on a representative sample from Germany. Importantly, we explored the role of demographic variables, interest in science and technology, and personality traits associated with psychological anthropomorphism in determining perceived acceptance of service robots in everyday life. Overall, attitudes towards service robots turned out to be relatively positive. Moreover, demographic variables (e.g., gender, occupation), interest in science and technology, and dispositional correlates of anthropomorphism had a significant impact on attitudes towards such assistive technology.
Application of the Novint Falcon haptic device as an actuator in real-time control
Authors: Block Daniel J. , Michelotti Mark B. , Sreenivas Ramavarapu S. 
Published: April 2015

AbstractThis paper describes the development of an embedded system whose purpose is to control the Novint Falcon as a robot, and to develop a control experiment that demonstrates the use the Novint Falcon as a robotic actuator. The Novint Falcon, which is a PC input device, is “haptic” in the sense that it has a force feedback component. Its relatively low cost compared with other platforms makes it a good candidate for academic application in robot modeling and control. An embedded system is developed to interface with the multiple motors and sensors present in the Novint Falcon, which is subsequently used to control three independent Novint Falcons for a “ballon- plate” experiment. The results show that the device is a viable solution for high-speed actuation of small-scale mechanical systems.
Cooperative localization of underwater robots with unsynchronized clocks
Authors: Bethencourt Aymeric , Jaulin Luc 
Published: April 2015

AbstractThis paper proposes an interval based approach for localizing a group of underwater robots with unsynchronized clocks. We use sonar communication and consider that the travel time of the sonar waves cannot be neglected, e.g. when the robots are fast and far-spaced. Therefore we cannot suppose that we measure a true distance between robots at the same time, but between robots at di􀉼erent times. Moreover, as the clocks of the robots are unsynchronized, the emitting and receiving times of the sonar waves are uncertain. To solve this problem, we cast the state equations of our robots as a constraint satisfaction problem and consider the sonar measurements as intertemporal constraints on uncertain times. We introduce the notion of interval of function to encompass the robots trajectory and clock with their uncertainty. We then use interval propagation to successively contract these intervals around the true position and clock of the robots. Several test cases are provided, with both simulated and experimental results.
Relationship between CEO remuneration and company financial performance in the South African retail and consumer goods sector
Authors: Bussin Mark , Nel Morne 
Published: April 2015

Purpose: This study was motivated by the need to better understand the effects of the global financial crisis in 2008 on the relationship between company financial performance and CEO guaranteed cost to company (CTC). The aim of this study was to understand the relationship between company financial performance using DuPont analysis and CEO guaranteed CTC in the South African retail and consumer goods sector.Design: The research was a quantitative, archival study of companies listed on the Johannesburg Stock Exchange (JSE), measured over a period of six years (2006–2011). The statistical analysis included regression and correlation analysis.Findings: The research found that CEO guaranteed CTC has shown no sensitivity towards company financial performance in terms of DuPont analysis over the six-year period, which included the global financial crises in 2008. Furthermore, a negative relationship existed between the return on equity and the guaranteed CTC of CEOs in the retail and consumer goods sector during this period.Practical implications: The findings suggest that there is misalignment between company strategy and performance and the guaranteed CTC of CEOs. A practical implication would be to have independent and competent remuneration committees ensuring alignment of the interests of a company with those of its leaders in this regard.
Free Riding, Upsizing, and Energy Efficiency Incentives in Maryland Homes
Authors: Alberini Anna , Gans Will , Towe Charles 
Published: April 2015

We use a unique dataset that combines an original survey of households, information about the structural characteristics of their homes, utility-provided electricity usage records and program participation status, to study the uptake of energy efficiency incentives and their effect on residential electricity consumption. Attention is restricted to homes where heating and cooling is provided exclusively by air-source heat pumps. We deploy a difference-in-difference study design and find that replacing a heat pump with a new one does reduce electricity usage by 8% on average. The effect differs dramatically across households based upon whether they receive an incentive towards the purchase of a new heat pump. Among incentive recipients, the effect is small, and the larger the incentive, the smaller the reduction in electricity usage. These findings suggest that capital costs are incorporated into the (long-term) cost of energy, generating an apparent rebound effect that is much more pronounced for incentive recipients.
Use of Primary Care Emergency Services in Norway: Impact of Birth Country and Duration of Residence
Authors: Goth Ursula Småland , Godager Geir 
Published: April 2015

Objective: In Norway, the General Practitioner Scheme was established in 2001. Satisfaction with the system is generally high. However, people often choose to visit community-based emergency wards (EW) for routine care instead. The aim of this paper is to describe which factors influence the choice of seeking care at the EW.Design, setting, and patients: Prior national research on utilization patterns has been based mostly on surveys showing a low response rate. By using merged register data, we analyzed the choice of the EW as a care provider in Oslo (Norway) for 2006 and 2007. Applying 1,934,248 observations of 279,531 different individuals, we estimated the probability of choosing the emergency ward for the Norwegian-born population as well as for the14-largest immigrant groups. Substantial variation between groups was identified.Main outcome: The proportion of EW visits was highest among patients from Somalia (11.7 percent) while the lowest proportion of EW users was among immigrants from Germany and Vietnam (5.3 percent). The results vary substantially within individual migrant groups; gender, age, and the duration of residence each influence the probability of visiting an EW.Conclusions: We found large differences in the probability of using an EW between individuals from immigrant populations, presumably because of barriers in access to primary care. Continuity in the physician–patient relationship is an important policy goal. A suggestion for policy is thus to improve communication about the organization of the Norwegian health-care sector to newly arrived immigrants, as well as to patients at the EW. For Appendix klick on "Supplementary Files" in the right hand menu
The Need for a New Paradigm in Scandinavian Health Economics
Authors: Mooney Gavin , Tinghög Gustav , Kalkan Almina 
Published: April 2015

This paper argues that the discipline of health economics has lost its way due to its persistent focus on individualistic and consequential values. The paper suggests how this might be remedied in both theory and practice. It proposes a new paradigm for health economics, which focuses on communitarian values. This new paradigm is discussed in the context of the Scandinavian welfare model.
The association between age and mortality related hospital expenditures: Evidence from a complete national registry
Authors: Gregersen Fredrik Alexander , Godager Geir 
Published: April 2015

The aim of this paper is to contribute to the debate on population aging and growth in health expenditures, by providing precise estimates on how mortality related expenditures are influenced by age. Using a complete register of inpatient hospital admissions to create gender-cohort specific panels for each of the 430 Norwegian municipalities, we are able to identify mortality related hospital expenditures by separating the impact of mortality on current hospital expenditures from the impact of patients’ age and gender. We apply model estimates to quantify the mortality-related hospital expenditures for twenty age groups. The results suggest that mortality-related hospital expenditures are a decreasing function of age. Furthermore, the results clearly suggest that, both age and mortalities should be included when predicting future health care expenditures. The estimation results suggest that 9.2 % of all hospital expenditures is associated with treating individuals in their last year of life. Our results also suggest that the reduction in mortality rates in the period from 1998 to 2009 have, cet. par. contributed to an estimated reduction in total hospital expenditures of 0.6 billion NOK, a difference corresponding to 2 % of the expenditures in 2009. (The appendix can be found under "Supplementary Files" in the menu to the right)
PERETTI, Cristina de & RODRÍGUEZ MARCIEL, Cristina (eds.), 12 pensadores (y uno más) para el siglo XXI, Madrid, Dykinson, 2014.
Authors: Sánchez Meca Diego 
Published: April 2015

Reseña del libro de PERETTI, Cristina de &amp; RODRÍGUEZ MARCIEL, Cristina (eds.), <em>12 pensadores (y uno más) para el siglo XXI</em>, Madrid, Dykinson, 2014.