bluuebunny/crossref_metadata_2025 huggingface dataset:
Maintenance of Gas Pipeline Automatic Block Valves
Authors: da Cruz Thales B. , de Novaes Márcia G. , Leite João Paulo de B.
Published: December 2014

The concept of gas pipelines sectionalized by block valves in Brazil has focused on safety rather than operability, and so all such valves are automatically controlled. However, operational history has indicated that undesired actuation of automatically controlled blocking valves is among the major risks of supply failure. Thus, a statistical study was carried out to identify the chief causes for undesired closures and opportunities for improvements. One of the most important causes is the lack of standardization of equipment and procedures within the pipeline network. The lack of standardization usually results in higher costs and complexity of operation and maintenance.

With the purpose of overcoming such drawbacks, it was required to establish a program for process optimization, in order to obtain well-adjusted maintenance and operational procedures throughout the life cycle of the equipment and facilities. A maintenance strategy for the automatic block valves is an important point to achieve the objectives defined in this program, such as an increase in operational reliability, minimizing the risks of gas-supply failure and the reduction of operational costs.

Although the project is still in progress, it is already possible to observe some positive outcomes related to operational reliability, showing a significant reduction in the number of operational occurrences of automatic block valves in 2013.
Inspection and Prioritization Methods for Small Diameter Auxiliary Piping
Authors: Pecush Adam , McTavish Mark , Ellestad Brian
Published: December 2014

To serve the pumping and storage needs of its customers; Enbridge operates more than 25 terminals and 150 pump stations across North America. In each of these facilities, small diameter (NPS 6 and smaller) piping is used in auxiliary systems including instrumentation, measurement, and product re-injection. Traditionally, in the design of facilities, this small piping has received less attention than large diameter process lines and, during construction, has typically been field run based on standard installation details. This, in conjunction with 65 years of changing design and construction philosophies, as well as asset acquisitions, has resulted in a wide variety of installation configurations across the Enbridge liquids system.

The Small Diameter Piping Program in the Facilities Integrity group centrally manages the integrity of all small diameter auxiliary piping across the Enbridge liquids system. Historically, the management and remediation of small diameter systems has been based on addressing specific installation types identified through incident investigations. While generally effective at minimizing re-occurrence, this approach has been limited in its ability to proactively identify installations that should be addressed.

In support of our goal of zero incidents, Enbridge has developed a proactive methodology for the inspection and prioritization of small diameter auxiliary piping. Installation types are evaluated on their susceptibility to specific damage mechanisms.

An inspection and prioritization model was developed through the combination of internal lessons learned and prioritization methodologies outlined in industry publications, specifically those from the overseas oil and gas industry. This model, sets a standardized process to assign a likelihood of failure (LOF) score to individual small diameter installations of specific types and/or functions.

Presently, likelihood of failure scores are used to identify installations requiring remediation, and to most effectively prioritize system-wide remediation activities. Over time, these scores will also be used to demonstrate an overall reduction in the likelihood of failure for small diameter piping in the Enbridge liquids pipeline system.
Triggers for the Transient State of a Pipeline in Material Balance Systems Used in Real-Time Transient Hydraulic Modeling
Authors: Rostamy Noorallah , Okungbowa Norense , Yurchevich John D.
Published: December 2014

Computational Pipeline Monitoring (CPM) leak detection in liquid pipelines can be unreliable or have a high number of false alarms during transient hydraulic events. This paper presents techniques for avoiding these false alarms and for improving leak detectability during steady state operations. Application of this approach has improved both the sensitivity and reliability of CPM-based leak detection systems. When a pipeline is in steady-state operation, the leak detection thresholds can be reduced. When a transient is detected, the thresholds are increased to a higher value. Because of known errors in data measurement and the time at which the measurement was made, large uncertainties in the line-pack prediction can exist during these transient events. In this paper, CPM reliability is improved using dual thresholds; tight threshold for near steady state and relaxed threshold for transient operation. In the presented study, different transient triggers in a pipeline have been implemented to the dual threshold method in order to show the effect of transient thresholds on the reliability of the CPM models or the reduction in the number of false alarms. When the CPM model determines that a transient event is occurring, the imbalance threshold is increased to a pre-set higher value. The transient threshold will remain high until the transient event diminishes, then the thresholds will return to their original steady-state value after a pre-set wait period. This applies to each leak detection window and to each flow meter-to-flow meter section in the CPM model. Detailed information about the dual thresholds approach and the transient triggers is provided in the full paper. Results from the implementation of this method and the quantitative improvement of the CPM reliability and sensitivity will also be presented.
Experiments and Finite Element Model Results on the Deformation Response of an X80 Weld Zone
Authors: Puydt Q. , Kulakov M. , Poole W. J. , Collins L. E. , Kenny S.
Published: December 2014

The modification of microstructure and mechanical properties of steels after a welding process has received considerable attention in the literature. In the case of welding HSLA steels for pipeline applications, the filler metal employed usually is overmatched (i.e. higher strength) compared to base metal to avoid fracture in this zone of the weld. For this reason, considerable work has emphasized microstructure evolution in the heat affected zone and the associated modification of mechanical properties in this region. In this study, the combined effect of microstructure/property distribution and the geometry of the weld are examined to understand where localization, necking and fracture occurs under tensile loading of a laboratory weld.

To achieve that, a series of tests were conducted on two different types of X80 submerged arc welds: Single and tandem wire welds. The tensile samples were machined transverse to the weld on plates 16 mm thick. Samples were tested where the geometry of the weld was preserved (i.e. the weld cap is left intact) and where the cap was removed in order to remove its effect. The local plastic strain during testing was determined using the Digital Image Correlation technique (DIC).

For the single wire weld, the influence of the cap geometry seems to be of second order, as the fracture location is the same with or without caps. But for the tandem wire welding, the fracture location is very different depending on the geometry: In the case where caps are kept, the fracture occurs outside the HAZ, in the base metal suggesting the important interplay between local mechanical properties and the weld geometry.

A Finite Element Model (FEM) was developed to gain insight into the geometrical effects on the local strain field distribution. The experimental strain distribution is compared to the FEM results to rationalize the effect of geometry. The model results are then used to discuss the position of fracture for the different samples, which correspond well to the experimental results.
How Safe Failure Pressure Ratios are Related to %SMYS
Authors: Kariyawasam Shahani , Huang Terry
Published: December 2014

Majority of the pipeline operators manage corrosion using inline inspection (ILI). ILIs enable operators to choose which anomalies should be excavated and, on the flip side, which anomalies are safe to remain on the pipe. If the remaining anomalies grow to a critical size before the next ILI cycle there will be in-service failure. This is avoided by forecasting the growth of the measured defects appropriately and assessing them for future integrity.

When an ILI is performed on a pipeline the ILI vendor reports the anomaly sizes, burst pressures and the Failure Pressure Ratios for each anomaly. Failure Pressure Ratio (FPR) for an anomaly is defined as the burst pressure divided by the Maximum allowable operation pressure (MAOP). In order to avoid ruptures, operators will excavate anomalies that have a limiting value of FPR. These limiting values are also referred to as response criteria, excavation criteria, safe failure pressure ratios, or safety factors. As the FPR depends heavily on the operating stress (or %SMYS) the limiting FPR value, below which we respond, should also depend on %SMYS. However, currently there is inconsistency in the use of response criteria in the industry. Some utilize the same response criteria for all pipe irrespective of %SMYS. This study shows that using the same limiting FPR does not provide the same level of safety for different %SMYS scenarios. It shows that the size of remaining anomalies in the lower %SMYS pipe would be significantly larger than in higher %SMYS pipe, leading to lower reliability in pipelines that have lower %SMYS. For gas pipelines, these lower %SMYS pipelines are often in higher location class pipelines with higher consequences of failure.

In other words, even though the FPR value is the same for two anomalies in two different %SMYS pipes, the two anomalies would have very different probabilities of failure, where one anomaly could be safe while the other is not.

This paper examines the ranges of FPR and the safe response criteria as a function of %SMYS. It examines the remaining anomaly sizes in different %SMYS pipe as allowed by current standards. The effect of the uncertainties on the response criteria due to measurement errors, material and geometric properties and model errors are also examined. It examines the response criteria in different jurisdictions. The effect of using different assessment equations, such as Modified B31G or RSTRENG, on the response criteria is also discussed. In order to obtain consistent safety, the consideration of %SMYS and consequences in defining a response criterion is discussed.

Many sets of ILI data, which have pipe in different %SMYS, have been assessed in order to examine practical ranges of FPR with %SMYS. The practical implications of different response criteria are studied and discussed.
A Semi-Quantitative Risk Assessment to Support Oil Pipeline Risk-Based Design
Authors: Mitchell James , Jasper Steve , Mihell Jim
Published: December 2014

During the regulatory phase of the Enbridge Northern Gateway Project (Northern Gateway), the Joint Review Panel (JRP) requested information on “how the risk factors resulting from the geotechnical and geographic aspects of the pipeline will be taken into account” and to demonstrate “the integration of risk factors with the environmental and socio-economic consequences from potential hydrocarbon releases”. Furthermore, the JRP required Northern Gateway to identify where a risk-based approach to design would be used to address geotechnical and seismic hazards, valve locations for spill consequence reduction and risk reduction in consequence areas”. [1]

To meet this requirement a semi-quantitative risk assessment (SQRA) was undertaken. Risk was defined as a function of probability and consequence, where the probability (expressed as a frequency) of loss of pipe integrity was quantitatively determined and the consequence of failure was qualitatively determined. The frequency of failure was a probabilistic combination of the calculated probability of failure from reliability methods, historical frequencies and assessed geo-hazard failure frequency rates. Consequence scoring was based on intersection of theoretical spills with “consequence areas” for environmental or socio-economic effects Frequency and consequence were then combined to provide risk scoring and ranking.

Failure frequencies were developed using reliability methods where appropriate. The use of reliability methods addresses the primary challenge associated with quantifying risk for new pipelines as industry failure statistics are not directly applicable to modern pipeline designs, materials, and operating practices. In the pipeline industry, reliability models exist for the most significant threats, including third-party damage, internal corrosion and external corrosion. In addition, geotechnical threats can be characterized in terms of expected magnitude and associated frequency of occurrence, thereby enabling pipeline reliability to be established for each geo-hazard.

Consequence scoring was based on modeling full bore rupture spill scenarios and determining whether these spills would potentially intersect identified “consequence areas”.

Over the course of the application and hearing process two SQRA’s were undertaken. Following the filing of the first SQRA, additional measures were included in the pipeline design to reduce the frequency of failure and to reduce potential consequences. This resulted in the calculated overall risk being reduced by a factor of 84%, primarily due to increases in wall thickness resulting in a reduction in the likelihood of 3rd party damage and in a reduction of consequence by an increased number of valves.
Critical Pipeline Failures and Rare-Events Data
Authors: Kendrick Andrew W.
Published: December 2014

This paper presents the severe and often times game-changing limitations associated with our observational learning mode and the ineffective knowledge base that results from it. More specifically, this paper stands our current approach of pipeline risk assessment on its head, describing how “rare-events” data, as they relate to significant pipeline failures, are simply not being addressed by our probabilistic risk analyses and modern statistical approaches. Further, risk blindness has been shown to consistently minimize the perception of high-consequence risk in the corporate world. Touching on themes from Nassim Taleb’s book, The Black Swan [1], this paper is about those failure events that lie outside the realm of regular possibility. Such events would never have been convincingly predicted prior to their occurrence, and yet they carry an extreme impact. Note that just because a failure was catastrophic does not necessarily mean it was a Black Swan. For example the financial melt down of 1982 was a catastrophe, but it was not a black swan. There have been numerous pipeline failures over the years that were quite catastrophic, but which were not Black Swans as referenced in this paper. They were neglect. It is important not to confuse the two.
Real Time Facility Monitoring: Lessons Learned
Authors: McKay Mike , Badawy Wael
Published: December 2014

This paper discusses monitoring solutions that address the emerging requirements of both security of critical infrastructure as well as liquid leak detection systems in remote locations. It analyses the requirements of different standards such as CSA Z.246 and CSA Z662 and other regulations in Canada, then it proposes solutions, and evaluates the performance, issues, and lessons learned through these deployments and operations. It also demonstrates the performance of a typical video monitoring system and proposes metrics to evaluate remote monitoring solutions.
Back to the Future Using Root Cause Analysis as a Proactive Risk Management Tool
Authors: Nidd Phillip , Thorn Terence , Porter Monica K.
Published: December 2014

Root Cause Analysis (RCA) can be an effective proactive methodology to forecast or predict probable events even before they occur. It’s use has been embraced by regulators and can be found in the most advanced management tools such as the recently published ISO 55000 series of international management standards for asset management.

An RCA identifies both the obvious and the underlying causes of an event so that specific solutions can be implemented. A complete RCA consists of a clear definition of the issue, a thorough analysis supported with evidence and a specific action plant for implementing solutions. In this respect, what may have appeared as a material failure or “human error,” can often be shown to be the result of an inadequate infrastructure management systems or the failure of management processes.

Generally thought of as a reactive method of identifying the causes of past incidents, this paper will describe the elements of an RCA and how it can be a powerful tool to identify systems or behaviors that when modified or corrected, will prevent recurrence of similar outcomes.
An Integrated Approach to Welding, AUT and ECA for Pipeline Construction
Authors: Horsley David , Ma Jing , van der Ent Jan , Wassink Casper , Fingerhut Martin
Published: December 2014

An integrated approach for the development of welding, inspection, and alternative weld flaw acceptance criteria, as used for girth welds during pipeline construction is presented. Welding is typically the pace limiting step during pipeline construction and is critical element of pipeline integrity. As such it is vital that it be completed efficiently and with high quality. Each of these three elements is vitally important to welding productivity and quality. At the core of the approach is the coordination of the three elements such that they are developed in concert. By this coordinated effort, all design options are considered leading to optimization of the final outcome. The approach is described by providing an example alternative weld flaw acceptance criteria, and giving the logic pertaining to choices of welding setup, AUT setup, the standard used for design and construction, and the impact of choices within these three elements on the final outcome. The paper illustrates the importance of a unified approach on weld productivity and quality.
The Development of a Facilities Integrity Management Program Recommended Practice for Canadian Energy Pipelines
Authors: Sahney Reena , Reed Mike , Skibinsky Darren
Published: December 2014

The Canadian Energy Pipeline Association (CEPA) is a voluntary, non-profit industry association representing major Canadian transmission pipeline companies. With the advent of changes in both CSA Z6621 as well as the National Energy Board Onshore Pipeline Regulations (OPR)2, the membership determined a Recommended Practice regarding a Management Systems Approach for Facilities Integrity was needed. As such, the Pipeline Integrity Working Group (PIWG) within CEPA formed a task group to support the initiative. The outlined approach was intended to have two main philosophical underpinnings: it must comprehensively support safe pipeline system operations and it must provide a practical mechanism for implementing a management systems approach for Facilities Iintegrity.

The main challenge in developing a framework for a Facilities Integrity Management System lies in the broad range of equipment and system types that the management system must encompass. That is, equipment, in the context of Facilities Integrity Management, must encompass not only station equipment (such as rotating equipment, valves, meters etc.,) but also categories such as high pressure station piping and fuel lines. Further, there was the recognition that Operators already have an array of tools, processes and techniques in place to manage their various equipment and systems. In light of these observations, the Recommended Practice describes a framework that uses major equipment types as a key differentiator. This is an approach that can be easily aligned with existing corporate computerized maintenance management systems (CMMS) such as SAP™ or Maximo™. Once the equipment categorization has been established, the Recommended Practice then provides guidance regarding the specific requirements that should be addressed for each equipment category based on the framework in CSA Z662-11 Annex N. Specific suggestions are provided in the areas of: alignment with corporate goals and objectives, scope, definitions, performance metrics, risk assessments, competency of personnel, change management as well as documentation. The approach also maximizes the opportunity to leverage existing systems and processes to the extent possible.

Overall the Recommended Practice should provide operators with a practical way to achieve a greater degree of rigor and alignment of facilities integrity management while ensuring detailed study and analysis is focused in the most appropriate areas.
Full-Scale Testing for Strain-Based Design Pipelines: Lessons Learned and Recommendations
Authors: Fairchild Doug P. , Shafrova Svetlana , Tang Huang , Crapps Justin M. , Cheng Wentao
Published: December 2014

There are generally two reasons for conducting full-scale tests (FSTs) for the measurement of pipe or weld strain capacity, (1) to generate data useful in verifying the accuracy of a strain capacity prediction model, or (2) to test materials being considered for use. The former case involves exploring variables important to the scope of the model, while the latter involves project specific materials and girth weld procedures often combined with upper bound cases of weld misalignment. Because the challenge of strain-based design is relatively new, FSTs should be used for both reasons cited above.

This paper provides observations, lessons learned, and recommendations regarding full-scale pipe strain capacity tests. This information has been developed through the conduct, witness, or review of 159 FSTs.

One of the most important aspects of full-scale testing is the preparation of welded pipe test specimens. It is imperative that the specimens be fabricated with materials of known properties and that all possible measures be taken to limit variations from the intended specimen design. It has been observed that unexpected results are often due to irregularities in pipe material strength, weld strength, weld toughness, or the presence of unintended weld defects in a specimen designed to contain just man-made defects. Post-test fractography and metallurgical examination are very useful in explaining the performance of a FST; therefore, failure analysis is discussed.
Strain Capacity Prediction of Strain-Based Pipelines
Authors: Tang Huang , Fairchild Doug , Panico Michele , Crapps Justin , Cheng Wentao
Published: December 2014

Strain-based design (SBD) is used to complement conventional allowable stress design for pipelines operated in environments with potentially large ground movements such as those found in permafrost and seismically active regions. Reliable and accurate prediction of tensile strain capacity (TSC) plays a critical role in strain-based design. As reported previously over the past 6+ years, a comprehensive experimental and numerical program was undertaken to characterize the TSC of welded pipelines, develop a finite element analysis (FEA) approach and equations capable of predicting TSC, and establish a strain-based engineering critical assessment (SBECA) methodology. The previous FEA model and TSC equations were validated against about 50 full-scale pipe strain capacity tests and are accurate within the validated variable ranges. In the current paper, enhancements of the previous model and equations are described. The enhancements include incorporation of advanced damage mechanics modeling into TSC prediction, development of a new TSC equation, expansion of variable ranges and functionality upgrades. The new model and equation are applicable over larger ranges of material properties and flaw sizes. The new FEA model is also used to establish surface flaw interaction rules for SBD. The new FEA model is validated against more than 40 full-scale non-pressurized and pressurized tests and underpins the development of the new TSC equation. The equation is validated against a total of 93 full-scale tests (FST). In addition to the enhancements, sample applications of the TSC model and equation are presented in the paper, for example, an investigation of the effects on strain capacity of Lüders strain and ductile tearing. Challenges in predicting TSC are also addressed.
Adults With Down Syndrome Performed Repetitive Movements Fast With Continuous Music Cues
Authors: Ringenbach Shannon D.R. , Zimmerman Kristina , Chen Chih Chia , Mulvey Genna M. , Holzapfel Simon D. , Weeks Daniel J. , Thaut Michael H.
Published: December 2014

The present study used a synchronization-continuation paradigm during continuous bimanual drumming with different cues in 17 persons with Down syndrome, eight typical persons with similar mental age and eight typical persons with similar chronological age. The task required participants to hit two drums with their hands at the same time following music (e.g., a tune with various decibel drum beats), auditory (e.g., sound of drumbeat), verbal (e.g., voice saying “drum”), and visual (e.g., video of both hands moving up and down and hitting the drums together) cues for 10 seconds, then continue drumming in the absence of cues for another 10 seconds. In general, when all groups were following the music cues their movements were faster as compared with their movements in the auditory, verbal, and visual conditions. In addition, when following visual cues all groups produced more accurate and consistently coordinated movements than with the other cue types. Further, participants with Down syndrome often stopped moving when the pacing cues were eliminated indicating a need for continuous cues for continuous movements.
Gene expression in asthmatic airway smooth muscle: a mixed bag
Authors: Pascoe Christopher D. , Swyngedouw Nicholas E. , Seow Chun Y. , Paré Peter D.
Published: December 2014

It has long been known that airway smooth muscle (ASM) contraction contributes significantly to the reversible airflow obstruction that defines asthma. It has also been postulated that phenotypic changes in ASM contribute to the airway hyper-responsiveness (AHR) that is a characteristic feature of asthma. Although there is agreement that the mass of ASM surrounding the airways is significantly increased in asthmatic compared with non-asthmatic airways, it is still uncertain whether there are quantitative or qualitative changes in the level of expression of the genes and proteins involved in the canonical contractile pathway in ASM that could account for AHR. This review will summarize past attempts at quantifying gene expression changes in the ASM of asthmatic lungs as well as non-asthmatic ASM cells stimulated with various inflammatory cytokines. The lack of consistent findings in asthmatic samples coupled with the relative concordance of results from stimulated ASM cells suggests that changes to the contractility of ASM tissues in asthma may be dependent on the presence of an inflammatory environment surrounding the ASM layer. Removal of the ASM from this environment could explain why hypercontractility is rarely seen ex vivo.
Protective Role of Oryeongsan Against Renal Inflammation and Glomerulosclerosis in db/db Mice
Authors: Yoon Jung Joo , Lee Yun Jung , Kang Dae Gill , Lee Ho Sub
Published: December 2014

Diabetic nephropathy is characterized by renal hardening and interstitial fibrosis caused by extracellular matrix (ECM) accumulation. The most distinctive diabetic lesion in the glomeruli is mesangial expansion and hyperplasia, which ultimately leads to diabetic nephrosclerosis. Oryeongsan (ORS), a traditional Chinese herbal medication, is widely used to treat nephrosis, dropsy, and uremia. In this study, type 2 diabetic animals (db/db mice) were administered ORS (100 mg/kg/day) for 8 weeks to examine the potential beneficial effects on metabolic abnormalities and diabetic nephropathy progression, including renal fibrosis. The body weight, total-cholesterol, triglyceride, and LDL-c levels were significantly decreased in ORS-treated db/db mice compared to untreated db/db mice. In addition, the blood glucose, insulin, glucose tolerance, and the homeostasis model assessment of insulin resistance index (HOMA-IR) were significantly improved in ORS-treated db/db mice compared to untreated db/db mice. Creatinine clearance (Ccr), urine albumin, and BUN levels were also improved by ORS treatment. The ratio of mesangial matrix/glomerular area was markedly higher in db/db mice than in db/m mice, but ORS significantly reduced this expansion. TGF-β1, Smad-2/-4, Collagen IV, CTGF, and TIMP decreased with ORS treatment, as were Smad-7 and MT1-MMP in ORS-treated db/db mice. Furthermore, ICAM-1 and MCP-1 expression were suppressed in ORS-treated db/db mice. Therefore, these findings suggest that ORS ameliorated insulin resistance and diabetes-associated glomerulosclerosis in db/db mice, possibly by disturbing the TGF-β1/Smads pathway. ORS may be a new therapeutic option for treating diabetic nephropathy.
Semi-Automatic Online Tagging with K-Medoid Clustering
Authors: Hu He , Du Xiaoyong
Published: December 2014

Online tagging is crucial for the acquisition and organization of web knowledge. We present TYG (Tag-as-You-Go) in this paper, a web browser extension for online tagging of personal knowledge on standard web pages. We investigate an approach to combine a K-Medoid-style clustering algorithm with the user input to achieve semi-automatic web page annotation. The annotation process supports user-defined tagging schema and comprises an automatic mechanism that is built upon clustering techniques, which can automatically group similar HTML DOM nodes into clusters corresponding to the user specification. TYG is a prototype system illustrating the proposed approach. Experiments with TYG show that our approach can achieve both efficiency and effectiveness in real world annotation scenarios.
Learning Non-Taxonomic Relations on Demand for Ontology Extension
Authors: Xu Yan , Li Ge , Mou Lili , Lu Yangyang
Published: December 2014

Learning non-taxonomic relations becomes an important research topic in ontology extension. Most of the existing learning approaches are mainly based on expert crafted corpora. These approaches are normally domain-specific and the corpora acquisition is laborious and costly. On the other hand, based on the static corpora, it is not able to meet personalized needs of semantic relations discovery for various taxonomies. In this paper, we propose a novel approach for learning non-taxonomic relations on demand. For any supplied taxonomy, it can focus on the segment of the taxonomy and collect information dynamically about the taxonomic concepts by using Wikipedia as a learning source. Based on the newly generated corpus, non-taxonomic relations are acquired through three steps: a) semantic relatedness detection; b) relations extraction between concepts; and c) relations generalization within a hierarchy. The proposed approach is evaluated on three different predefined taxonomies and the experimental results show that it is effective in capturing non-taxonomic relations as needed and has good potential for the ontology extension on demand.
Clustering Analysis of Function Call Sequence for Regression Test Case Reduction
Authors: Wang Rongcun , Huang Rubing , Lu Yansheng , Qu Binbin
Published: December 2014

Regression test case reduction aims at selecting a representative subset from the original test pool, while retaining the largest possible fault detection capability. Cluster analysis has been proposed and applied for selecting an effective test case subset in regression testing. It groups test cases into clusters based on the similarity of historical execution profiles. In previous studies, historical execution profiles are represented as binary or numeric function coverage vectors. The vector-based similarity approaches only consider which functions or statements are covered and the number of times they are executed. However, the vector-based approaches do not take the relations and sequential information between function calls into account. In this paper, we propose cluster analysis of function call sequences to attempt to improve the fault detection effectiveness of regression testing even further. A test is represented as a function call sequence that includes the relations and sequential information between function calls. The distance between function call sequences is measured not only by the Levenshtein distance but also the Euclidean distance. To assess the effectiveness of our approaches, we designed and conducted experimental studies on five subject programs. The experimental results indicate that our approaches are statistically superior to the approaches based on the similarity of vectors (i.e. binary vectors and numeric vectors), random and greedy function-coverage-based maximization test case reduction techniques in terms of fault detection effectiveness. With respective to the cost-effectiveness, cluster analysis of sequences measured using the Euclidean distance is more effective than using the Levenshtein distance.
Buckling Analysis of Mindlin Plates Under the Green–Lagrange Strain Hypothesis
Authors: Ruocco Eugenio , Minutolo Vincenzo
Published: December 2014

In the present paper, the influence of Green–Lagrange nonlinear strain-displacement terms, usually considered negligible under the von Kármán hypothesis, on the buckling of isotropic, moderately thick plates and shells, is investigated. The first order shear deformation plate theory is applied and the governing equations, containing nonlinear terms related to both in-plane displacement and out-of-plane rotations usually ignored in the literature, are derived using the principle of minimum of the strain energy. The general Levy type solution method is employed, and exact buckling loads and mode shapes are derived. To verify the accuracy of the solution obtained, comparisons with existing data are first made. Then, through graphics and tables, the effect of the nonlinear strain-displacement terms for a range of boundary and load conditions, variations of aspect ratio, thickness ratio and changes in geometry is presented. The results obtained show that the von Kármán's model can sensibly overestimate the critical load for structures characterized by the modes involving comparable in-plane and out-of-plane displacements.
Ionic conductivity and dielectric studies of LiClO4 doped poly(vinylalcohol)(PVA)/chitosan(CS) composites
Authors: Rathod Sunil G. , Bhajantri R. F. , Ravindrachary V. , Pujari P. K. , Sheela T.
Published: December 2014

This paper focuses on the dielectric constant (ε′), dielectric loss factor (ε″) and frequency dependent conductivity (σac) properties of newly prepared poly(vinylalcohol) (PVA) chitosan (CS) composite films incorporated with different concentrations of LiClO 4. The composite films were prepared using solution casting technique. The complexation between salt and polymer host is confirmed by FT Raman and UV-Vis studies. The sample containing 20 wt.% LiClO 4 exhibits a highest ionic conductivity of 3 × 10-6 S/cm at room temperature. The dielectric properties of the composites follow non-Debye behavior.
Automatic and Portable Mapping of Data Parallel Programs to OpenCL for GPU-Based Heterogeneous Systems
Authors: Wang Zheng , Grewe Dominik , O’boyle Michael F. P.
Published: December 2014

General-purpose GPU-based systems are highly attractive, as they give potentially massive performance at little cost. Realizing such potential is challenging due to the complexity of programming. This article presents a compiler-based approach to automatically generate optimized OpenCL code from data parallel OpenMP programs for GPUs. A key feature of our scheme is that it leverages existing transformations, especially data transformations, to improve performance on GPU architectures and uses automatic machine learning to build a predictive model to determine if it is worthwhile running the OpenCL code on the GPU or OpenMP code on the multicore host. We applied our approach to the entire NAS parallel benchmark suite and evaluated it on distinct GPU-based systems. We achieved average (up to) speedups of 4.51× and 4.20× (143× and 67×) on Core i7/NVIDIA GeForce GTX580 and Core i7/AMD Radeon 7970 platforms, respectively, over a sequential baseline. Our approach achieves, on average, greater than 10× speedups over two state-of-the-art automatic GPU code generators.
Querying a web of linked data
Authors: Hartig Olaf
Published: December 2014

During recent years a set of best practices for publishing and connecting structured data on the World Wide Web (WWW) has emerged. These best practices are referred to as the Linked Data principles and the resulting form of Web data is called
Linked Data
. The increasing adoption of these principles has lead to the creation of a globally distributed space of Linked Data that covers various domains such as government, libraries, life sciences, and media. Approaches that conceive this data space as a huge distributed database and enable an execution of declarative queries over this database hold an enormous potential; they allow users to benefit from a virtually unbounded set of up-to-date data. As a consequence, several research groups have started to study such approaches. However, the main focus of existing work is to address practical challenges that arise in this context. Research on the foundations of such approaches is largely missing. This dissertation closes this gap.
GRT
Authors: Wang Tao , Sun Guangyu , Chen Jiahua , Gong Jian , Wu Haoyang , Li Xiaoguang , Lu Songwu , Cong Jason
Published: December 2014

The importance of software-defined radio (SDR) continues to increase. However, existing SDR platforms become less efficient as the wireless industry moves towards Gigabit WiFi. In this work, we propose a novel reconfigurable SDR platform named GRT. With the help of reconfigurable architecture and corresponding software support, SDR designs on GRT can leverage high performance of the underlying hardware and provide sufficient usability, including the support for efficient modular design, commodity interface, good programmability, code reusability, etc. We implement an 802.11a/g WiFi system on GRT to evaluate its performance. The results demonstrate that GRT can achieve a substantial improvement in usability while still satisfying the performance requirement.
Performance Evaluations of Graph Database using CUDA and OpenMP Compatible Libraries
Authors: Morishima Shin , Matsutani Hiroki
Published: December 2014

Graph databases use graph structures to store data sets as nodes, edges, and properties. They are used to store and search the relationships between a large number of nodes, such as social networking services and recommendation engines that use customer social graphs. Since computation cost for graph search queries increases as the graph becomes large, in this pa- per we accelerate the graph search functions (Dijkstra and A* algorithms) of a graph database Neo4j using two ways: multi- threaded library and CUDA library for graphics processing units (GPUs). We use 100,000-node graphs generated based on a degree distribution of Facebook social graph for evaluations. Our multi-threaded and GPU-based implementations require an auxiliary adjacency matrix for a target graph. The results show that, when we do not take into account additional overhead to generate the auxiliary adjacency matrix, multi-threaded version improves the Dijkstra and A* search performance by 16.2x and 13.8x compared to the original implementation. The GPU-based implementation improves the Dijkstra and A* search performance by 26.2x and 32.8x. When we take into account the overhead, although the speed-ups by our implementations are reduced, by reusing the auxiliary adjacency matrix for multiple graph search queries we can significantly improve the graph search performance.
Energy efficient Reconfigurable Computing with Adaptive Voltage and Logic scaling
Authors: Nunez-Yanez Jose
Published: December 2014

This paper investigates a novel energy-proportional concept that combines closed-loop voltage scalability and run-time hardware reconfiguration. Voltage scaling is based on in-situ detectors that allow the device to detect valid working voltage and frequency pairs at run-time. The combined approach named AVLS (Adaptive Voltage and Logic Scaling) enables the adaptation of capacitance, voltage and frequency to obtain power and energy savings based on workload, process and operating conditions in a closed-loop configuration. The technique is applied to a reconfigurable motion estimation processor that can be configured with a variable number of execution units and it is used as a test vehicle. The results demonstrate that the proposed voltage scaling can obtain up to 85% reduction in energy compared with nominal voltage operation at the same frequency. This efficient energy point is obtained at a voltage of 0.62 V and frequency of 56 MHz compared with running the core at the same frequency and nominal 1 V. The addition of logic scalability means that if enough device resources are available a parallel configuration with six execution units operating at 0.62 V reduces energy by up to 95% compared with a single execution unit operating at 1 V and the same frequency.
An Iterative and Truthful MultiUnit Auction Scheme for Coordinated Sharing of Spectrum White Spaces
Authors: Manickam Saravana , Marina Mahesh K. , Pediaditaki Sofia , Nekovee Maziar
Published: December 2014

We consider the use of dynamic auctions for coordinating spectrum sharing among secondary users, and propose an online multi-unit, iterative auction mechanism called VERUM that is truthful and efficient (the item is always won by the bidder who values it the most). VERUM is an adaptation of the well known Ausubel's clinching auction [1] to suit the dynamic spectrum sharing context. As a use case for VERUM, we consider TV white space (TVWS) spectrum sharing among home networks, and compare VERUM with two existing efficient and truthful multi-unit spectrum auction schemes, VERITAS and SATYA. Our evaluations, using real distributions of homes in a dense urban neighborhood in London and realistic TVWS spectrum availability maps for the UK, show that VERUM outperforms the other two schemes in terms of revenue, spectrum utilization and percentage of winning bidders.
Fair, Flexible and Feasible ISP Billing
Authors: Raja Vamseedhar Reddyvari , Shakkottai Srinivas , Dhamdhere Amogh , claffy kc
Published: December 2014

The 95th percentile method for calculating a customer's billable transit volume has been the industry standard used by transit providers for over a decade due to its simplicity. We recently showed [1] that 95th percentile billing can be unfair, in that it does not reflect a customer's contribution to the provider's peak load. The 95th percentile method is also inflexible, as it does not allow a provider to offer incentives to customers that contribute minimally to the provider's peak load. In this paper we propose a new transit billing optimization framework that is fair, flexible and computationally inexpensive. Our approach is based on the Provision Ratio, a metric that estimates the contribution of a customer to the provider's peak traffic. The proposed mechanism has fairness properties similar to the optimal (in terms of fairness) Shapley value allocation, with a much smaller computational complexity.
Network Security and Contagion
Authors: Acemoglu Daron , Malekian Azarakhsh , Ozdaglar Asu
Published: December 2014

This paper develops a theoretical model of investments in security in a network of interconnected agents. The network connections introduce the possibility of cascading failures depending on exogenous or endogenous attacks and the profile of security investments by the agents. The general presumption in the literature, based on intuitive arguments or analysis of symmetric networks, is that because security investments create positive externalities on other agents, there will be underinvestment in security. We show that this reasoning is incomplete because of a first-order economic force: security investments are also strategic substitutes. In a general (non-symmetric) network, this implies that underinvestment by some agents will encourage overinvestment by others. We demonstrate by means of examples that not only there will be overinvestment by some agents but also aggregate probabilities of infection can be lower in equilibrium than in the social optimum. We then provide sufficient conditions for underinvestment. This requires both sufficiently convex cost functions (just convexity is not enough) and networks that are either symmetric or locally tree-like (i.e., either trees or in the case of stochastic networks, without local cycles with high probability). We also characterize the impact of network structure on equilibrium and optimal investments. Finally, we show that when the attack location is endogenized (by assuming that the attacker chooses a probability distribution over the location of the attack in order to maximize damage), there is another reason for overinvestment: greater investment by an agent shifts the attack to other parts of the network.
Energy Consumption of Content Distribution from Nano Data Centers versus Centralized Data Centers
Authors: Jalali Fatemeh , Ayre Rob , Vishwanath Arun , Hinton Kerry , Alpcan Tansu , Tucker Rod
Published: December 2014

Energy consumption of nano data centers has recently been a topic of interest as they emerge as a novel computing and storage platform. We present end-to-end energy consumption models for nano data centers and its centralized counterpart. To assess the energy consumption of nano and centralized data centers, we propose flowbased and time-based energy consumption models for shared and single user network equipment. To evaluate our models, a set of measurements and practical experiments are performed. Our results indicate that nano data centers might lead to energy savings depending on various factors such as location of nano servers, type of access network attached to nano servers, and the ratio of active time to idle time of nano servers. Thus, nano data centers can complement centralized ones and lead to savings energy if certain applications are off-loadable from centralized data centers.
Transient Antiphospholipid Syndrome Associated with Primary Cytomegalovirus Infection: A Case Report and Literature Review
Authors: Nakayama Tsuyoshi , Akahoshi Mitsuteru , Irino Kensuke , Kimoto Yasutaka , Arinobu Yojiro , Niiro Hiroaki , Tsukamoto Hiroshi , Horiuchi Takahiko , Akashi Koichi
Published: December 2014

Viral infection is known to induce transient autoimmunity in humans. Acute cytomegalovirus (CMV) infection is implicated in occasional thrombosis formation. We here, for the first time, report a 19-year-old female who had an acute CMV infection, leading to a deep venous thrombosis and a pulmonary embolism along with transient appearance of lupus anticoagulant. The pathological role of antiphospholipid antibodies in CMV-mediated thrombosis is discussed.