The Validation by Measurement Theory of Proposed Object-Oriented Software Metrics

NASA Technical Reports Server (NTRS)

Neal, Ralph D.

1996-01-01

Moving software development into the engineering arena requires controllability, and to control a process, it must be measurable. Measuring the process does no good if the product is not also measured, i.e., being the best at producing an inferior product does not define a quality process. Also, not every number extracted from software development is a valid measurement. A valid measurement only results when we are able to verify that the number is representative of the attribute that we wish to measure. Many proposed software metrics are used by practitioners without these metrics ever having been validated, leading to costly but often useless calculations. Several researchers have bemoaned the lack of scientific precision in much of the published software measurement work and have called for validation of software metrics by measurement theory. This dissertation applies measurement theory to validate fifty proposed object-oriented software metrics.

The validation by measurement theory of proposed object-oriented software metrics

NASA Technical Reports Server (NTRS)

Neal, Ralph D.

1994-01-01

Moving software development into the engineering arena requires controllability, and to control a process, it must be measurable. Measuring the process does no good if the product is not also measured, i.e., being the best at producing an inferior product does not define a quality process. Also, not every number extracted from software development is a valid measurement. A valid measurement only results when we are able to verify that the number is representative of the attribute that we wish to measure. Many proposed software metrics are used by practitioners without these metrics ever having been validated, leading to costly but often useless calculations. Several researchers have bemoaned the lack of scientific precision in much of the published software measurement work and have called for validation of software metrics by measurement theory. This dissertation applies measurement theory to validate fifty proposed object-oriented software metrics (Li and Henry, 1993; Chidamber and Kemerrer, 1994; Lorenz and Kidd, 1994).

Spatial-temporal distortion metric for in-service quality monitoring of any digital video system

NASA Astrophysics Data System (ADS)

Wolf, Stephen; Pinson, Margaret H.

1999-11-01

Many organizations have focused on developing digital video quality metrics which produce results that accurately emulate subjective responses. However, to be widely applicable a metric must also work over a wide range of quality, and be useful for in-service quality monitoring. The Institute for Telecommunication Sciences (ITS) has developed spatial-temporal distortion metrics that meet all of these requirements. These objective metrics are described in detail and have a number of interesting properties, including utilization of (1) spatial activity filters which emphasize long edges on the order of 10 arc min while simultaneously performing large amounts of noise suppression, (2) the angular direction of the spatial gradient, (3) spatial-temporal compression factors of at least 384:1 (spatial compression of at least 64:1 and temporal compression of at least 6:1, and 4) simple perceptibility thresholds and spatial-temporal masking functions. Results are presented that compare the objective metric values with mean opinion scores from a wide range of subjective data bases spanning many different scenes, systems, bit-rates, and applications.

An Underwater Color Image Quality Evaluation Metric.

PubMed

Yang, Miao; Sowmya, Arcot

2015-12-01

Quality evaluation of underwater images is a key goal of underwater video image retrieval and intelligent processing. To date, no metric has been proposed for underwater color image quality evaluation (UCIQE). The special absorption and scattering characteristics of the water medium do not allow direct application of natural color image quality metrics especially to different underwater environments. In this paper, subjective testing for underwater image quality has been organized. The statistical distribution of the underwater image pixels in the CIELab color space related to subjective evaluation indicates the sharpness and colorful factors correlate well with subjective image quality perception. Based on these, a new UCIQE metric, which is a linear combination of chroma, saturation, and contrast, is proposed to quantify the non-uniform color cast, blurring, and low-contrast that characterize underwater engineering and monitoring images. Experiments are conducted to illustrate the performance of the proposed UCIQE metric and its capability to measure the underwater image enhancement results. They show that the proposed metric has comparable performance to the leading natural color image quality metrics and the underwater grayscale image quality metrics available in the literature, and can predict with higher accuracy the relative amount of degradation with similar image content in underwater environments. Importantly, UCIQE is a simple and fast solution for real-time underwater video processing. The effectiveness of the presented measure is also demonstrated by subjective evaluation. The results show better correlation between the UCIQE and the subjective mean opinion score.

Pragmatic quality metrics for evolutionary software development models

NASA Technical Reports Server (NTRS)

Royce, Walker

1990-01-01

Due to the large number of product, project, and people parameters which impact large custom software development efforts, measurement of software product quality is a complex undertaking. Furthermore, the absolute perspective from which quality is measured (customer satisfaction) is intangible. While we probably can't say what the absolute quality of a software product is, we can determine the relative quality, the adequacy of this quality with respect to pragmatic considerations, and identify good and bad trends during development. While no two software engineers will ever agree on an optimum definition of software quality, they will agree that the most important perspective of software quality is its ease of change. We can call this flexibility, adaptability, or some other vague term, but the critical characteristic of software is that it is soft. The easier the product is to modify, the easier it is to achieve any other software quality perspective. This paper presents objective quality metrics derived from consistent lifecycle perspectives of rework which, when used in concert with an evolutionary development approach, can provide useful insight to produce better quality per unit cost/schedule or to achieve adequate quality more efficiently. The usefulness of these metrics is evaluated by applying them to a large, real world, Ada project.

The compressed average image intensity metric for stereoscopic video quality assessment

NASA Astrophysics Data System (ADS)

Wilczewski, Grzegorz

2016-09-01

The following article depicts insights towards design, creation and testing of a genuine metric designed for a 3DTV video quality evaluation. The Compressed Average Image Intensity (CAII) mechanism is based upon stereoscopic video content analysis, setting its core feature and functionality to serve as a versatile tool for an effective 3DTV service quality assessment. Being an objective type of quality metric it may be utilized as a reliable source of information about the actual performance of a given 3DTV system, under strict providers evaluation. Concerning testing and the overall performance analysis of the CAII metric, the following paper presents comprehensive study of results gathered across several testing routines among selected set of samples of stereoscopic video content. As a result, the designed method for stereoscopic video quality evaluation is investigated across the range of synthetic visual impairments injected into the original video stream.

Towards a Visual Quality Metric for Digital Video

NASA Technical Reports Server (NTRS)

Watson, Andrew B.

1998-01-01

The advent of widespread distribution of digital video creates a need for automated methods for evaluating visual quality of digital video. This is particularly so since most digital video is compressed using lossy methods, which involve the controlled introduction of potentially visible artifacts. Compounding the problem is the bursty nature of digital video, which requires adaptive bit allocation based on visual quality metrics. In previous work, we have developed visual quality metrics for evaluating, controlling, and optimizing the quality of compressed still images. These metrics incorporate simplified models of human visual sensitivity to spatial and chromatic visual signals. The challenge of video quality metrics is to extend these simplified models to temporal signals as well. In this presentation I will discuss a number of the issues that must be resolved in the design of effective video quality metrics. Among these are spatial, temporal, and chromatic sensitivity and their interactions, visual masking, and implementation complexity. I will also touch on the question of how to evaluate the performance of these metrics.

Development of a perceptually calibrated objective metric of noise

NASA Astrophysics Data System (ADS)

Keelan, Brian W.; Jin, Elaine W.; Prokushkin, Sergey

2011-01-01

A system simulation model was used to create scene-dependent noise masks that reflect current performance of mobile phone cameras. Stimuli with different overall magnitudes of noise and with varying mixtures of red, green, blue, and luminance noises were included in the study. Eleven treatments in each of ten pictorial scenes were evaluated by twenty observers using the softcopy ruler method. In addition to determining the quality loss function in just noticeable differences (JNDs) for the average observer and scene, transformations for different combinations of observer sensitivity and scene susceptibility were derived. The psychophysical results were used to optimize an objective metric of isotropic noise based on system noise power spectra (NPS), which were integrated over a visual frequency weighting function to yield perceptually relevant variances and covariances in CIE L*a*b* space. Because the frequency weighting function is expressed in terms of cycles per degree at the retina, it accounts for display pixel size and viewing distance effects, so application-specific predictions can be made. Excellent results were obtained using only L* and a* variances and L*a* covariance, with relative weights of 100, 5, and 12, respectively. The positive a* weight suggests that the luminance (photopic) weighting is slightly narrow on the long wavelength side for predicting perceived noisiness. The L*a* covariance term, which is normally negative, reflects masking between L* and a* noise, as confirmed in informal evaluations. Test targets in linear sRGB and rendered L*a*b* spaces for each treatment are available at http://www.aptina.com/ImArch/ to enable other researchers to test metrics of their own design and calibrate them to JNDs of quality loss without performing additional observer experiments. Such JND-calibrated noise metrics are particularly valuable for comparing the impact of noise and other attributes, and for computing overall image quality.

Perceptual video quality assessment in H.264 video coding standard using objective modeling.

PubMed

Karthikeyan, Ramasamy; Sainarayanan, Gopalakrishnan; Deepa, Subramaniam Nachimuthu

2014-01-01

Since usage of digital video is wide spread nowadays, quality considerations have become essential, and industry demand for video quality measurement is rising. This proposal provides a method of perceptual quality assessment in H.264 standard encoder using objective modeling. For this purpose, quality impairments are calculated and a model is developed to compute the perceptual video quality metric based on no reference method. Because of the shuttle difference between the original video and the encoded video the quality of the encoded picture gets degraded, this quality difference is introduced by the encoding process like Intra and Inter prediction. The proposed model takes into account of the artifacts introduced by these spatial and temporal activities in the hybrid block based coding methods and an objective modeling of these artifacts into subjective quality estimation is proposed. The proposed model calculates the objective quality metric using subjective impairments; blockiness, blur and jerkiness compared to the existing bitrate only calculation defined in the ITU G 1070 model. The accuracy of the proposed perceptual video quality metrics is compared against popular full reference objective methods as defined by VQEG.

A Validation of Object-Oriented Design Metrics

NASA Technical Reports Server (NTRS)

Basili, Victor R.; Briand, Lionel; Melo, Walcelio L.

1995-01-01

This paper presents the results of a study conducted at the University of Maryland in which we experimentally investigated the suite of Object-Oriented (00) design metrics introduced by [Chidamber and Kemerer, 1994]. In order to do this, we assessed these metrics as predictors of fault-prone classes. This study is complementary to [Lieand Henry, 1993] where the same suite of metrics had been used to assess frequencies of maintenance changes to classes. To perform our validation accurately, we collected data on the development of eight medium-sized information management systems based on identical requirements. All eight projects were developed using a sequential life cycle model, a well-known 00 analysis/design method and the C++ programming language. Based on experimental results, the advantages and drawbacks of these 00 metrics are discussed and suggestions for improvement are provided. Several of Chidamber and Kemerer's 00 metrics appear to be adequate to predict class fault-proneness during the early phases of the life-cycle. We also showed that they are, on our data set, better predictors than "traditional" code metrics, which can only be collected at a later phase of the software development processes.

Quality metrics for sensor images

NASA Technical Reports Server (NTRS)

Ahumada, AL

1993-01-01

Methods are needed for evaluating the quality of augmented visual displays (AVID). Computational quality metrics will help summarize, interpolate, and extrapolate the results of human performance tests with displays. The FLM Vision group at NASA Ames has been developing computational models of visual processing and using them to develop computational metrics for similar problems. For example, display modeling systems use metrics for comparing proposed displays, halftoning optimizing methods use metrics to evaluate the difference between the halftone and the original, and image compression methods minimize the predicted visibility of compression artifacts. The visual discrimination models take as input two arbitrary images A and B and compute an estimate of the probability that a human observer will report that A is different from B. If A is an image that one desires to display and B is the actual displayed image, such an estimate can be regarded as an image quality metric reflecting how well B approximates A. There are additional complexities associated with the problem of evaluating the quality of radar and IR enhanced displays for AVID tasks. One important problem is the question of whether intruding obstacles are detectable in such displays. Although the discrimination model can handle detection situations by making B the original image A plus the intrusion, this detection model makes the inappropriate assumption that the observer knows where the intrusion will be. Effects of signal uncertainty need to be added to our models. A pilot needs to make decisions rapidly. The models need to predict not just the probability of a correct decision, but the probability of a correct decision by the time the decision needs to be made. That is, the models need to predict latency as well as accuracy. Luce and Green have generated models for auditory detection latencies. Similar models are needed for visual detection. Most image quality models are designed for static imagery

Software Quality Metrics Enhancements. Volume 1

DTIC Science & Technology

1980-04-01

the mathematical relationships which relate metrics to ratings of the various quality factors) for factors which were not validated previously were...function, provides a mathematical relationship between the metrics and the quality factors. (3) Validation of these normalization functions was performed by...samples, further research is needed before a high degree of confidence can be placed on the mathematical relationships established to date l (3.3.3) 6

A guide to calculating habitat-quality metrics to inform conservation of highly mobile species

USGS Publications Warehouse

Bieri, Joanna A.; Sample, Christine; Thogmartin, Wayne E.; Diffendorfer, James E.; Earl, Julia E.; Erickson, Richard A.; Federico, Paula; Flockhart, D. T. Tyler; Nicol, Sam; Semmens, Darius J.; Skraber, T.; Wiederholt, Ruscena; Mattsson, Brady J.

2018-01-01

Many metrics exist for quantifying the relative value of habitats and pathways used by highly mobile species. Properly selecting and applying such metrics requires substantial background in mathematics and understanding the relevant management arena. To address this multidimensional challenge, we demonstrate and compare three measurements of habitat quality: graph-, occupancy-, and demographic-based metrics. Each metric provides insights into system dynamics, at the expense of increasing amounts and complexity of data and models. Our descriptions and comparisons of diverse habitat-quality metrics provide means for practitioners to overcome the modeling challenges associated with management or conservation of such highly mobile species. Whereas previous guidance for applying habitat-quality metrics has been scattered in diversified tracks of literature, we have brought this information together into an approachable format including accessible descriptions and a modeling case study for a typical example that conservation professionals can adapt for their own decision contexts and focal populations.Considerations for Resource ManagersManagement objectives, proposed actions, data availability and quality, and model assumptions are all relevant considerations when applying and interpreting habitat-quality metrics.Graph-based metrics answer questions related to habitat centrality and connectivity, are suitable for populations with any movement pattern, quantify basic spatial and temporal patterns of occupancy and movement, and require the least data.Occupancy-based metrics answer questions about likelihood of persistence or colonization, are suitable for populations that undergo localized extinctions, quantify spatial and temporal patterns of occupancy and movement, and require a moderate amount of data.Demographic-based metrics answer questions about relative or absolute population size, are suitable for populations with any movement pattern, quantify demographic

Degraded visual environment image/video quality metrics

NASA Astrophysics Data System (ADS)

Baumgartner, Dustin D.; Brown, Jeremy B.; Jacobs, Eddie L.; Schachter, Bruce J.

2014-06-01

A number of image quality metrics (IQMs) and video quality metrics (VQMs) have been proposed in the literature for evaluating techniques and systems for mitigating degraded visual environments. Some require both pristine and corrupted imagery. Others require patterned target boards in the scene. None of these metrics relates well to the task of landing a helicopter in conditions such as a brownout dust cloud. We have developed and used a variety of IQMs and VQMs related to the pilot's ability to detect hazards in the scene and to maintain situational awareness. Some of these metrics can be made agnostic to sensor type. Not only are the metrics suitable for evaluating algorithm and sensor variation, they are also suitable for choosing the most cost effective solution to improve operating conditions in degraded visual environments.

Objective evaluation of interior noise booming in a passenger car based on sound metrics and artificial neural networks.

PubMed

Lee, Hyun-Ho; Lee, Sang-Kwon

2009-09-01

Booming sound is one of the important sounds in a passenger car. The aim of the paper is to develop the objective evaluation method of interior booming sound. The development method is based on the sound metrics and ANN (artificial neural network). The developed method is called the booming index. Previous work maintained that booming sound quality is related to loudness and sharpness--the sound metrics used in psychoacoustics--and that the booming index is developed by using the loudness and sharpness for a signal within whole frequency between 20 Hz and 20 kHz. In the present paper, the booming sound quality was found to be effectively related to the loudness at frequencies below 200 Hz; thus the booming index is updated by using the loudness of the signal filtered by the low pass filter at frequency under 200 Hz. The relationship between the booming index and sound metric is identified by an ANN. The updated booming index has been successfully applied to the objective evaluation of the booming sound quality of mass-produced passenger cars.

Evaluation of image quality metrics for the prediction of subjective best focus.

PubMed

Kilintari, Marina; Pallikaris, Aristophanis; Tsiklis, Nikolaos; Ginis, Harilaos S

2010-03-01

Seven existing and three new image quality metrics were evaluated in terms of their effectiveness in predicting subjective cycloplegic refraction. Monochromatic wavefront aberrations (WA) were measured in 70 eyes using a Shack-Hartmann based device (Complete Ophthalmic Analysis System; Wavefront Sciences). Subjective cycloplegic spherocylindrical correction was obtained using a standard manifest refraction procedure. The dioptric amount required to optimize each metric was calculated and compared with the subjective refraction result. Metrics included monochromatic and polychromatic variants, as well as variants taking into consideration the Stiles and Crawford effect (SCE). WA measurements were performed using infrared light and converted to visible before all calculations. The mean difference between subjective cycloplegic and WA-derived spherical refraction ranged from 0.17 to 0.36 diopters (D), while paraxial curvature resulted in a difference of 0.68 D. Monochromatic metrics exhibited smaller mean differences between subjective cycloplegic and objective refraction. Consideration of the SCE reduced the standard deviation (SD) of the difference between subjective and objective refraction. All metrics exhibited similar performance in terms of accuracy and precision. We hypothesize that errors pertaining to the conversion between infrared and visible wavelengths rather than calculation method may be the limiting factor in determining objective best focus from near infrared WA measurements.

Image quality metrics for volumetric laser displays

NASA Astrophysics Data System (ADS)

Williams, Rodney D.; Donohoo, Daniel

1991-08-01

This paper addresses the extensions to the image quality metrics and related human factors research that are needed to establish the baseline standards for emerging volume display technologies. The existing and recently developed technologies for multiplanar volume displays are reviewed with an emphasis on basic human visual issues. Human factors image quality metrics and guidelines are needed to firmly establish this technology in the marketplace. The human visual requirements and the display design tradeoffs for these prototype laser-based volume displays are addressed and several critical image quality issues identified for further research. The American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSIHFS-100) and other international standards (ISO, DIN) can serve as a starting point, but this research base must be extended to provide new image quality metrics for this new technology for volume displays.

Objective Amplitude of Accommodation Computed from Optical Quality Metrics Applied to Wavefront Outcomes

PubMed Central

López-Gil, Norberto; Fernández-Sánchez, Vicente; Thibos, Larry N.; Montés-Micó, Robert

2010-01-01

Purpose We studied the accuracy and precision of 32 objective wavefront methods for finding the amplitude of accommodation obtained in 180 eyes. Methods Ocular accommodation was stimulated with 0.5 D steps in target vergence spanning the full range of accommodation for each subject. Subjective monocular amplitude of accommodation was measured using two clinical methods, using negative lenses and with a custom Badal optometer. Results Both subjective methods gave similar results. Results obtained from the Badal optometer where used to test the accuracy of the objective methods. All objective methods showed lower amplitude of accommodation that the subjective ones by an amount that varied from 0.2 to 1.1 D depending on the method. The precision in this prediction also varied between subjects, with an average standard error of the mean of 0.1 D that decreased with age. Conclusions Depth of field increases subjective of amplitude of accommodation overestimating the objective amplitude obtained with all the metrics used. The change in the negative direction of spherical aberration during accommodation increases the amplitude of accommodation by an amount that varies with age.

Validation of a Quality Management Metric

DTIC Science & Technology

2000-09-01

quality management metric (QMM) was used to measure the performance of ten software managers on Department of Defense (DoD) software development programs. Informal verification and validation of the metric compared the QMM score to an overall program success score for the entire program and yielded positive correlation. The results of applying the QMM can be used to characterize the quality of software management and can serve as a template to improve software management performance. Future work includes further refining the QMM, applying the QMM scores to provide feedback

Systems Engineering Metrics: Organizational Complexity and Product Quality Modeling

NASA Technical Reports Server (NTRS)

Mog, Robert A.

1997-01-01

Innovative organizational complexity and product quality models applicable to performance metrics for NASA-MSFC's Systems Analysis and Integration Laboratory (SAIL) missions and objectives are presented. An intensive research effort focuses on the synergistic combination of stochastic process modeling, nodal and spatial decomposition techniques, organizational and computational complexity, systems science and metrics, chaos, and proprietary statistical tools for accelerated risk assessment. This is followed by the development of a preliminary model, which is uniquely applicable and robust for quantitative purposes. Exercise of the preliminary model using a generic system hierarchy and the AXAF-I architectural hierarchy is provided. The Kendall test for positive dependence provides an initial verification and validation of the model. Finally, the research and development of the innovation is revisited, prior to peer review. This research and development effort results in near-term, measurable SAIL organizational and product quality methodologies, enhanced organizational risk assessment and evolutionary modeling results, and 91 improved statistical quantification of SAIL productivity interests.

Getting started on metrics - Jet Propulsion Laboratory productivity and quality

NASA Technical Reports Server (NTRS)

Bush, M. W.

1990-01-01

A review is presented to describe the effort and difficulties of reconstructing fifteen years of JPL software history. In 1987 the collection and analysis of project data were started with the objective of creating laboratory-wide measures of quality and productivity for software development. As a result of this two-year Software Product Assurance metrics study, a rough measurement foundation for software productivity and software quality, and an order-of-magnitude quantitative baseline for software systems and subsystems are now available.

Automatic extraction and visualization of object-oriented software design metrics

NASA Astrophysics Data System (ADS)

Lakshminarayana, Anuradha; Newman, Timothy S.; Li, Wei; Talburt, John

2000-02-01

Software visualization is a graphical representation of software characteristics and behavior. Certain modes of software visualization can be useful in isolating problems and identifying unanticipated behavior. In this paper we present a new approach to aid understanding of object- oriented software through 3D visualization of software metrics that can be extracted from the design phase of software development. The focus of the paper is a metric extraction method and a new collection of glyphs for multi- dimensional metric visualization. Our approach utilize the extensibility interface of a popular CASE tool to access and automatically extract the metrics from Unified Modeling Language class diagrams. Following the extraction of the design metrics, 3D visualization of these metrics are generated for each class in the design, utilizing intuitively meaningful 3D glyphs that are representative of the ensemble of metrics. Extraction and visualization of design metrics can aid software developers in the early study and understanding of design complexity.

New Objective Refraction Metric Based on Sphere Fitting to the Wavefront.

PubMed

Jaskulski, Mateusz; Martínez-Finkelshtein, Andreí; López-Gil, Norberto

2017-01-01

To develop an objective refraction formula based on the ocular wavefront error (WFE) expressed in terms of Zernike coefficients and pupil radius, which would be an accurate predictor of subjective spherical equivalent (SE) for different pupil sizes. A sphere is fitted to the ocular wavefront at the center and at a variable distance, t . The optimal fitting distance, t opt , is obtained empirically from a dataset of 308 eyes as a function of objective refraction pupil radius, r 0 , and used to define the formula of a new wavefront refraction metric (MTR). The metric is tested in another, independent dataset of 200 eyes. For pupil radii r 0 ≤ 2 mm, the new metric predicts the equivalent sphere with similar accuracy (<0.1D), however, for r 0 > 2 mm, the mean error of traditional metrics can increase beyond 0.25D, and the MTR remains accurate. The proposed metric allows clinicians to obtain an accurate clinical spherical equivalent value without rescaling/refitting of the wavefront coefficients. It has the potential to be developed into a metric which will be able to predict full spherocylindrical refraction for the desired illumination conditions and corresponding pupil size.

Analysis of Network Clustering Algorithms and Cluster Quality Metrics at Scale

PubMed Central

Kobourov, Stephen; Gallant, Mike; Börner, Katy

2016-01-01

Overview Notions of community quality underlie the clustering of networks. While studies surrounding network clustering are increasingly common, a precise understanding of the realtionship between different cluster quality metrics is unknown. In this paper, we examine the relationship between stand-alone cluster quality metrics and information recovery metrics through a rigorous analysis of four widely-used network clustering algorithms—Louvain, Infomap, label propagation, and smart local moving. We consider the stand-alone quality metrics of modularity, conductance, and coverage, and we consider the information recovery metrics of adjusted Rand score, normalized mutual information, and a variant of normalized mutual information used in previous work. Our study includes both synthetic graphs and empirical data sets of sizes varying from 1,000 to 1,000,000 nodes. Cluster Quality Metrics We find significant differences among the results of the different cluster quality metrics. For example, clustering algorithms can return a value of 0.4 out of 1 on modularity but score 0 out of 1 on information recovery. We find conductance, though imperfect, to be the stand-alone quality metric that best indicates performance on the information recovery metrics. Additionally, our study shows that the variant of normalized mutual information used in previous work cannot be assumed to differ only slightly from traditional normalized mutual information. Network Clustering Algorithms Smart local moving is the overall best performing algorithm in our study, but discrepancies between cluster evaluation metrics prevent us from declaring it an absolutely superior algorithm. Interestingly, Louvain performed better than Infomap in nearly all the tests in our study, contradicting the results of previous work in which Infomap was superior to Louvain. We find that although label propagation performs poorly when clusters are less clearly defined, it scales efficiently and accurately to large

A software quality model and metrics for risk assessment

NASA Technical Reports Server (NTRS)

Hyatt, L.; Rosenberg, L.

1996-01-01

A software quality model and its associated attributes are defined and used as the model for the basis for a discussion on risk. Specific quality goals and attributes are selected based on their importance to a software development project and their ability to be quantified. Risks that can be determined by the model's metrics are identified. A core set of metrics relating to the software development process and its products is defined. Measurements for each metric and their usability and applicability are discussed.

Quality Metrics in Neonatal and Pediatric Critical Care Transport: A National Delphi Project.

PubMed

Schwartz, Hamilton P; Bigham, Michael T; Schoettker, Pamela J; Meyer, Keith; Trautman, Michael S; Insoft, Robert M

2015-10-01

The transport of neonatal and pediatric patients to tertiary care facilities for specialized care demands monitoring the quality of care delivered during transport and its impact on patient outcomes. In 2011, pediatric transport teams in Ohio met to identify quality indicators permitting comparisons among programs. However, no set of national consensus quality metrics exists for benchmarking transport teams. The aim of this project was to achieve national consensus on appropriate neonatal and pediatric transport quality metrics. Modified Delphi technique. The first round of consensus determination was via electronic mail survey, followed by rounds of consensus determination in-person at the American Academy of Pediatrics Section on Transport Medicine's 2012 Quality Metrics Summit. All attendees of the American Academy of Pediatrics Section on Transport Medicine Quality Metrics Summit, conducted on October 21-23, 2012, in New Orleans, LA, were eligible to participate. Candidate quality metrics were identified through literature review and those metrics currently tracked by participating programs. Participants were asked in a series of rounds to identify "very important" quality metrics for transport. It was determined a priori that consensus on a metric's importance was achieved when at least 70% of respondents were in agreement. This is consistent with other Delphi studies. Eighty-two candidate metrics were considered initially. Ultimately, 12 metrics achieved consensus as "very important" to transport. These include metrics related to airway management, team mobilization time, patient and crew injuries, and adverse patient care events. Definitions were assigned to the 12 metrics to facilitate uniform data tracking among programs. The authors succeeded in achieving consensus among a diverse group of national transport experts on 12 core neonatal and pediatric transport quality metrics. We propose that transport teams across the country use these metrics to

Development of quality metrics for ambulatory pediatric cardiology: Infection prevention.

PubMed

Johnson, Jonathan N; Barrett, Cindy S; Franklin, Wayne H; Graham, Eric M; Halnon, Nancy J; Hattendorf, Brandy A; Krawczeski, Catherine D; McGovern, James J; O'Connor, Matthew J; Schultz, Amy H; Vinocur, Jeffrey M; Chowdhury, Devyani; Anderson, Jeffrey B

2017-12-01

In 2012, the American College of Cardiology's (ACC) Adult Congenital and Pediatric Cardiology Council established a program to develop quality metrics to guide ambulatory practices for pediatric cardiology. The council chose five areas on which to focus their efforts; chest pain, Kawasaki Disease, tetralogy of Fallot, transposition of the great arteries after arterial switch, and infection prevention. Here, we sought to describe the process, evaluation, and results of the Infection Prevention Committee's metric design process. The infection prevention metrics team consisted of 12 members from 11 institutions in North America. The group agreed to work on specific infection prevention topics including antibiotic prophylaxis for endocarditis, rheumatic fever, and asplenia/hyposplenism; influenza vaccination and respiratory syncytial virus prophylaxis (palivizumab); preoperative methods to reduce intraoperative infections; vaccinations after cardiopulmonary bypass; hand hygiene; and testing to identify splenic function in patients with heterotaxy. An extensive literature review was performed. When available, previously published guidelines were used fully in determining metrics. The committee chose eight metrics to submit to the ACC Quality Metric Expert Panel for review. Ultimately, metrics regarding hand hygiene and influenza vaccination recommendation for patients did not pass the RAND analysis. Both endocarditis prophylaxis metrics and the RSV/palivizumab metric passed the RAND analysis but fell out during the open comment period. Three metrics passed all analyses, including those for antibiotic prophylaxis in patients with heterotaxy/asplenia, for influenza vaccination compliance in healthcare personnel, and for adherence to recommended regimens of secondary prevention of rheumatic fever. The lack of convincing data to guide quality improvement initiatives in pediatric cardiology is widespread, particularly in infection prevention. Despite this, three metrics were

Quality metrics in high-dimensional data visualization: an overview and systematization.

PubMed

Bertini, Enrico; Tatu, Andrada; Keim, Daniel

2011-12-01

In this paper, we present a systematization of techniques that use quality metrics to help in the visual exploration of meaningful patterns in high-dimensional data. In a number of recent papers, different quality metrics are proposed to automate the demanding search through large spaces of alternative visualizations (e.g., alternative projections or ordering), allowing the user to concentrate on the most promising visualizations suggested by the quality metrics. Over the last decade, this approach has witnessed a remarkable development but few reflections exist on how these methods are related to each other and how the approach can be developed further. For this purpose, we provide an overview of approaches that use quality metrics in high-dimensional data visualization and propose a systematization based on a thorough literature review. We carefully analyze the papers and derive a set of factors for discriminating the quality metrics, visualization techniques, and the process itself. The process is described through a reworked version of the well-known information visualization pipeline. We demonstrate the usefulness of our model by applying it to several existing approaches that use quality metrics, and we provide reflections on implications of our model for future research. © 2010 IEEE

New Objective Refraction Metric Based on Sphere Fitting to the Wavefront

PubMed Central

Martínez-Finkelshtein, Andreí

2017-01-01

Purpose To develop an objective refraction formula based on the ocular wavefront error (WFE) expressed in terms of Zernike coefficients and pupil radius, which would be an accurate predictor of subjective spherical equivalent (SE) for different pupil sizes. Methods A sphere is fitted to the ocular wavefront at the center and at a variable distance, t. The optimal fitting distance, topt, is obtained empirically from a dataset of 308 eyes as a function of objective refraction pupil radius, r0, and used to define the formula of a new wavefront refraction metric (MTR). The metric is tested in another, independent dataset of 200 eyes. Results For pupil radii r0 ≤ 2 mm, the new metric predicts the equivalent sphere with similar accuracy (<0.1D), however, for r0 > 2 mm, the mean error of traditional metrics can increase beyond 0.25D, and the MTR remains accurate. The proposed metric allows clinicians to obtain an accurate clinical spherical equivalent value without rescaling/refitting of the wavefront coefficients. It has the potential to be developed into a metric which will be able to predict full spherocylindrical refraction for the desired illumination conditions and corresponding pupil size. PMID:29104804

Defining quality metrics and improving safety and outcome in allergy care.

PubMed

Lee, Stella; Stachler, Robert J; Ferguson, Berrylin J

2014-04-01

The delivery of allergy immunotherapy in the otolaryngology office is variable and lacks standardization. Quality metrics encompasses the measurement of factors associated with good patient-centered care. These factors have yet to be defined in the delivery of allergy immunotherapy. We developed and applied quality metrics to 6 allergy practices affiliated with an academic otolaryngic allergy center. This work was conducted at a tertiary academic center providing care to over 1500 patients. We evaluated methods and variability between 6 sites. Tracking of errors and anaphylaxis was initiated across all sites. A nationwide survey of academic and private allergists was used to collect data on current practice and use of quality metrics. The most common types of errors recorded were patient identification errors (n = 4), followed by vial mixing errors (n = 3), and dosing errors (n = 2). There were 7 episodes of anaphylaxis of which 2 were secondary to dosing errors for a rate of 0.01% or 1 in every 10,000 injection visits/year. Site visits showed that 86% of key safety measures were followed. Analysis of nationwide survey responses revealed that quality metrics are still not well defined by either medical or otolaryngic allergy practices. Academic practices were statistically more likely to use quality metrics (p = 0.021) and perform systems reviews and audits in comparison to private practices (p = 0.005). Quality metrics in allergy delivery can help improve safety and quality care. These metrics need to be further defined by otolaryngic allergists in the changing health care environment. © 2014 ARS-AAOA, LLC.

Analysis of Network Clustering Algorithms and Cluster Quality Metrics at Scale.

PubMed

Emmons, Scott; Kobourov, Stephen; Gallant, Mike; Börner, Katy

2016-01-01

Notions of community quality underlie the clustering of networks. While studies surrounding network clustering are increasingly common, a precise understanding of the realtionship between different cluster quality metrics is unknown. In this paper, we examine the relationship between stand-alone cluster quality metrics and information recovery metrics through a rigorous analysis of four widely-used network clustering algorithms-Louvain, Infomap, label propagation, and smart local moving. We consider the stand-alone quality metrics of modularity, conductance, and coverage, and we consider the information recovery metrics of adjusted Rand score, normalized mutual information, and a variant of normalized mutual information used in previous work. Our study includes both synthetic graphs and empirical data sets of sizes varying from 1,000 to 1,000,000 nodes. We find significant differences among the results of the different cluster quality metrics. For example, clustering algorithms can return a value of 0.4 out of 1 on modularity but score 0 out of 1 on information recovery. We find conductance, though imperfect, to be the stand-alone quality metric that best indicates performance on the information recovery metrics. Additionally, our study shows that the variant of normalized mutual information used in previous work cannot be assumed to differ only slightly from traditional normalized mutual information. Smart local moving is the overall best performing algorithm in our study, but discrepancies between cluster evaluation metrics prevent us from declaring it an absolutely superior algorithm. Interestingly, Louvain performed better than Infomap in nearly all the tests in our study, contradicting the results of previous work in which Infomap was superior to Louvain. We find that although label propagation performs poorly when clusters are less clearly defined, it scales efficiently and accurately to large graphs with well-defined clusters.

PSQM-based RR and NR video quality metrics

NASA Astrophysics Data System (ADS)

Lu, Zhongkang; Lin, Weisi; Ong, Eeping; Yang, Xiaokang; Yao, Susu

2003-06-01

This paper presents a new and general concept, PQSM (Perceptual Quality Significance Map), to be used in measuring the visual distortion. It makes use of the selectivity characteristic of HVS (Human Visual System) that it pays more attention to certain area/regions of visual signal due to one or more of the following factors: salient features in image/video, cues from domain knowledge, and association of other media (e.g., speech or audio). PQSM is an array whose elements represent the relative perceptual-quality significance levels for the corresponding area/regions for images or video. Due to its generality, PQSM can be incorporated into any visual distortion metrics: to improve effectiveness or/and efficiency of perceptual metrics; or even to enhance a PSNR-based metric. A three-stage PQSM estimation method is also proposed in this paper, with an implementation of motion, texture, luminance, skin-color and face mapping. Experimental results show the scheme can improve the performance of current image/video distortion metrics.

Sigma metrics used to assess analytical quality of clinical chemistry assays: importance of the allowable total error (TEa) target.

PubMed

Hens, Koen; Berth, Mario; Armbruster, Dave; Westgard, Sten

2014-07-01

Six Sigma metrics were used to assess the analytical quality of automated clinical chemistry and immunoassay tests in a large Belgian clinical laboratory and to explore the importance of the source used for estimation of the allowable total error. Clinical laboratories are continually challenged to maintain analytical quality. However, it is difficult to measure assay quality objectively and quantitatively. The Sigma metric is a single number that estimates quality based on the traditional parameters used in the clinical laboratory: allowable total error (TEa), precision and bias. In this study, Sigma metrics were calculated for 41 clinical chemistry assays for serum and urine on five ARCHITECT c16000 chemistry analyzers. Controls at two analyte concentrations were tested and Sigma metrics were calculated using three different TEa targets (Ricos biological variability, CLIA, and RiliBÄK). Sigma metrics varied with analyte concentration, the TEa target, and between/among analyzers. Sigma values identified those assays that are analytically robust and require minimal quality control rules and those that exhibit more variability and require more complex rules. The analyzer to analyzer variability was assessed on the basis of Sigma metrics. Six Sigma is a more efficient way to control quality, but the lack of TEa targets for many analytes and the sometimes inconsistent TEa targets from different sources are important variables for the interpretation and the application of Sigma metrics in a routine clinical laboratory. Sigma metrics are a valuable means of comparing the analytical quality of two or more analyzers to ensure the comparability of patient test results.

National evaluation of multidisciplinary quality metrics for head and neck cancer.

PubMed

Cramer, John D; Speedy, Sedona E; Ferris, Robert L; Rademaker, Alfred W; Patel, Urjeet A; Samant, Sandeep

2017-11-15

The National Quality Forum has endorsed quality-improvement measures for multiple cancer types that are being developed into actionable tools to improve cancer care. No nationally endorsed quality metrics currently exist for head and neck cancer. The authors identified patients with surgically treated, invasive, head and neck squamous cell carcinoma in the National Cancer Data Base from 2004 to 2014 and compared the rate of adherence to 5 different quality metrics and whether compliance with these quality metrics impacted overall survival. The metrics examined included negative surgical margins, neck dissection lymph node (LN) yield ≥ 18, appropriate adjuvant radiation, appropriate adjuvant chemoradiation, adjuvant therapy within 6 weeks, as well as overall quality. In total, 76,853 eligible patients were identified. There was substantial variability in patient-level adherence, which was 80% for negative surgical margins, 73.1% for neck dissection LN yield, 69% for adjuvant radiation, 42.6% for adjuvant chemoradiation, and 44.5% for adjuvant therapy within 6 weeks. Risk-adjusted Cox proportional-hazard models indicated that all metrics were associated with a reduced risk of death: negative margins (hazard ratio [HR] 0.73; 95% confidence interval [CI], 0.71-0.76), LN yield ≥ 18 (HR, 0.93; 95% CI, 0.89-0.96), adjuvant radiation (HR, 0.67; 95% CI, 0.64-0.70), adjuvant chemoradiation (HR, 0.84; 95% CI, 0.79-0.88), and adjuvant therapy ≤6 weeks (HR, 0.92; 95% CI, 0.89-0.96). Patients who received high-quality care had a 19% reduced adjusted hazard of mortality (HR, 0.81; 95% CI, 0.79-0.83). Five head and neck cancer quality metrics were identified that have substantial variability in adherence and meaningfully impact overall survival. These metrics are appropriate candidates for national adoption. Cancer 2017;123:4372-81. © 2017 American Cancer Society. © 2017 American Cancer Society.

Objectively Quantifying Radiation Esophagitis With Novel Computed Tomography–Based Metrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niedzielski, Joshua S., E-mail: jsniedzielski@mdanderson.org; University of Texas Houston Graduate School of Biomedical Science, Houston, Texas; Yang, Jinzhong

Purpose: To study radiation-induced esophageal expansion as an objective measure of radiation esophagitis in patients with non-small cell lung cancer (NSCLC) treated with intensity modulated radiation therapy. Methods and Materials: Eighty-five patients had weekly intra-treatment CT imaging and esophagitis scoring according to Common Terminlogy Criteria for Adverse Events 4.0, (24 Grade 0, 45 Grade 2, and 16 Grade 3). Nineteen esophageal expansion metrics based on mean, maximum, spatial length, and volume of expansion were calculated as voxel-based relative volume change, using the Jacobian determinant from deformable image registration between the planning and weekly CTs. An anatomic variability correction method wasmore » validated and applied to these metrics to reduce uncertainty. An analysis of expansion metrics and radiation esophagitis grade was conducted using normal tissue complication probability from univariate logistic regression and Spearman rank for grade 2 and grade 3 esophagitis endpoints, as well as the timing of expansion and esophagitis grade. Metrics' performance in classifying esophagitis was tested with receiver operating characteristic analysis. Results: Expansion increased with esophagitis grade. Thirteen of 19 expansion metrics had receiver operating characteristic area under the curve values >0.80 for both grade 2 and grade 3 esophagitis endpoints, with the highest performance from maximum axial expansion (MaxExp1) and esophageal length with axial expansion ≥30% (LenExp30%) with area under the curve values of 0.93 and 0.91 for grade 2, 0.90 and 0.90 for grade 3 esophagitis, respectively. Conclusions: Esophageal expansion may be a suitable objective measure of esophagitis, particularly maximum axial esophageal expansion and esophageal length with axial expansion ≥30%, with 2.1 Jacobian value and 98.6 mm as the metric value for 50% probability of grade 3 esophagitis. The uncertainty in esophageal Jacobian calculations can be reduced

A Novel Scoring Metrics for Quality Assurance of Ocean Color Observations

NASA Astrophysics Data System (ADS)

Wei, J.; Lee, Z.

2016-02-01

Interpretation of the ocean bio-optical properties from ocean color observations depends on the quality of the ocean color data, specifically the spectrum of remote sensing reflectance (Rrs). The in situ and remotely measured Rrs spectra are inevitably subject to errors induced by instrument calibration, sea-surface correction and atmospheric correction, and other environmental factors. Great efforts have been devoted to the ocean color calibration and validation. Yet, there exist no objective and consensus criteria for assessment of the ocean color data quality. In this study, the gap is filled by developing a novel metrics for such data quality assurance and quality control (QA/QC). This new QA metrics is not intended to discard "suspicious" Rrs spectra from available datasets. Rather, it takes into account the Rrs spectral shapes and amplitudes as a whole and grades each Rrs spectrum. This scoring system is developed based on a large ensemble of in situ hyperspectral remote sensing reflectance data measured from various aquatic environments and processed with robust procedures. This system is further tested with the NASA bio-Optical Marine Algorithm Data set (NOMAD), with results indicating significant improvements in the estimation of bio-optical properties when Rrs spectra marked with higher quality assurance are used. This scoring system is further verified with simulated data and satellite ocean color data in various regions, and we envision higher quality ocean color products with the implementation of such a quality screening system.

The Applicability of Proposed Object-Oriented Metrics to Developer Feedback in Time to Impact Development

NASA Technical Reports Server (NTRS)

Neal, Ralph D.

1996-01-01

This paper looks closely at each of the software metrics generated by the McCabe object-Oriented Tool(TM) and its ability to convey timely information to developers. The metrics are examined for meaningfulness in terms of the scale assignable to the metric by the rules of measurement theory and the software dimension being measured. Recommendations are made as to the proper use of each metric and its ability to influence development at an early stage. The metrics of the McCabe Object-Oriented Tool(TM) set were selected because of the tool's use in a couple of NASA IV&V projects.

Evaluating which plan quality metrics are appropriate for use in lung SBRT.

PubMed

Yaparpalvi, Ravindra; Garg, Madhur K; Shen, Jin; Bodner, William R; Mynampati, Dinesh K; Gafar, Aleiya; Kuo, Hsiang-Chi; Basavatia, Amar K; Ohri, Nitin; Hong, Linda X; Kalnicki, Shalom; Tome, Wolfgang A

2018-02-01

Several dose metrics in the categories-homogeneity, coverage, conformity and gradient have been proposed in literature for evaluating treatment plan quality. In this study, we applied these metrics to characterize and identify the plan quality metrics that would merit plan quality assessment in lung stereotactic body radiation therapy (SBRT) dose distributions. Treatment plans of 90 lung SBRT patients, comprising 91 targets, treated in our institution were retrospectively reviewed. Dose calculations were performed using anisotropic analytical algorithm (AAA) with heterogeneity correction. A literature review on published plan quality metrics in the categories-coverage, homogeneity, conformity and gradient was performed. For each patient, using dose-volume histogram data, plan quality metric values were quantified and analysed. For the study, the radiation therapy oncology group (RTOG) defined plan quality metrics were: coverage (0.90 ± 0.08); homogeneity (1.27 ± 0.07); conformity (1.03 ± 0.07) and gradient (4.40 ± 0.80). Geometric conformity strongly correlated with conformity index (p < 0.0001). Gradient measures strongly correlated with target volume (p < 0.0001). The RTOG lung SBRT protocol advocated conformity guidelines for prescribed dose in all categories were met in ≥94% of cases. The proportion of total lung volume receiving doses of 20 Gy and 5 Gy (V 20 and V 5 ) were mean 4.8% (±3.2) and 16.4% (±9.2), respectively. Based on our study analyses, we recommend the following metrics as appropriate surrogates for establishing SBRT lung plan quality guidelines-coverage % (ICRU 62), conformity (CN or CI Paddick ) and gradient (R 50% ). Furthermore, we strongly recommend that RTOG lung SBRT protocols adopt either CN or CI Padddick in place of prescription isodose to target volume ratio for conformity index evaluation. Advances in knowledge: Our study metrics are valuable tools for establishing lung SBRT plan quality guidelines.

SU-E-T-776: Use of Quality Metrics for a New Hypo-Fractionated Pre-Surgical Mesothelioma Protocol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richardson, S; Mehta, V

Purpose: The “SMART” (Surgery for Mesothelioma After Radiation Therapy) approach involves hypo-fractionated radiotherapy of the lung pleura to 25Gy over 5 days followed by surgical resection within 7. Early clinical results suggest that this approach is very promising, but also logistically challenging due to the multidisciplinary involvement. Due to the compressed schedule, high dose, and shortened planning time, the delivery of the planned doses were monitored for safety with quality metric software. Methods: Hypo-fractionated IMRT treatment plans were developed for all patients and exported to Quality Reports™ software. Plan quality metrics or PQMs™ were created to calculate an objective scoringmore » function for each plan. This allows for an objective assessment of the quality of the plan and a benchmark for plan improvement for subsequent patients. The priorities of various components were incorporated based on similar hypo-fractionated protocols such as lung SBRT treatments. Results: Five patients have been treated at our institution using this approach. The plans were developed, QA performed, and ready within 5 days of simulation. Plan Quality metrics utilized in scoring included doses to OAR and target coverage. All patients tolerated treatment well and proceeded to surgery as scheduled. Reported toxicity included grade 1 nausea (n=1), grade 1 esophagitis (n=1), grade 2 fatigue (n=3). One patient had recurrent fluid accumulation following surgery. No patients experienced any pulmonary toxicity prior to surgery. Conclusion: An accelerated course of pre-operative high dose radiation for mesothelioma is an innovative and promising new protocol. Without historical data, one must proceed cautiously and monitor the data carefully. The development of quality metrics and scoring functions for these treatments allows us to benchmark our plans and monitor improvement. If subsequent toxicities occur, these will be easy to investigate and incorporate into

Image-guided radiotherapy quality control: Statistical process control using image similarity metrics.

PubMed

Shiraishi, Satomi; Grams, Michael P; Fong de Los Santos, Luis E

2018-05-01

The purpose of this study was to demonstrate an objective quality control framework for the image review process. A total of 927 cone-beam computed tomography (CBCT) registrations were retrospectively analyzed for 33 bilateral head and neck cancer patients who received definitive radiotherapy. Two registration tracking volumes (RTVs) - cervical spine (C-spine) and mandible - were defined, within which a similarity metric was calculated and used as a registration quality tracking metric over the course of treatment. First, sensitivity to large misregistrations was analyzed for normalized cross-correlation (NCC) and mutual information (MI) in the context of statistical analysis. The distribution of metrics was obtained for displacements that varied according to a normal distribution with standard deviation of σ = 2 mm, and the detectability of displacements greater than 5 mm was investigated. Then, similarity metric control charts were created using a statistical process control (SPC) framework to objectively monitor the image registration and review process. Patient-specific control charts were created using NCC values from the first five fractions to set a patient-specific process capability limit. Population control charts were created using the average of the first five NCC values for all patients in the study. For each patient, the similarity metrics were calculated as a function of unidirectional translation, referred to as the effective displacement. Patient-specific action limits corresponding to 5 mm effective displacements were defined. Furthermore, effective displacements of the ten registrations with the lowest similarity metrics were compared with a three dimensional (3DoF) couch displacement required to align the anatomical landmarks. Normalized cross-correlation identified suboptimal registrations more effectively than MI within the framework of SPC. Deviations greater than 5 mm were detected at 2.8σ and 2.1σ from the mean for NCC and MI

Software metrics: The key to quality software on the NCC project

NASA Technical Reports Server (NTRS)

Burns, Patricia J.

1993-01-01

Network Control Center (NCC) Project metrics are captured during the implementation and testing phases of the NCCDS software development lifecycle. The metrics data collection and reporting function has interfaces with all elements of the NCC project. Close collaboration with all project elements has resulted in the development of a defined and repeatable set of metrics processes. The resulting data are used to plan and monitor release activities on a weekly basis. The use of graphical outputs facilitates the interpretation of progress and status. The successful application of metrics throughout the NCC project has been instrumental in the delivery of quality software. The use of metrics on the NCC Project supports the needs of the technical and managerial staff. This paper describes the project, the functions supported by metrics, the data that are collected and reported, how the data are used, and the improvements in the quality of deliverable software since the metrics processes and products have been in use.

Spread spectrum image watermarking based on perceptual quality metric.

PubMed

Zhang, Fan; Liu, Wenyu; Lin, Weisi; Ngan, King Ngi

2011-11-01

Efficient image watermarking calls for full exploitation of the perceptual distortion constraint. Second-order statistics of visual stimuli are regarded as critical features for perception. This paper proposes a second-order statistics (SOS)-based image quality metric, which considers the texture masking effect and the contrast sensitivity in Karhunen-Loève transform domain. Compared with the state-of-the-art metrics, the quality prediction by SOS better correlates with several subjectively rated image databases, in which the images are impaired by the typical coding and watermarking artifacts. With the explicit metric definition, spread spectrum watermarking is posed as an optimization problem: we search for a watermark to minimize the distortion of the watermarked image and to maximize the correlation between the watermark pattern and the spread spectrum carrier. The simple metric guarantees the optimal watermark a closed-form solution and a fast implementation. The experiments show that the proposed watermarking scheme can take full advantage of the distortion constraint and improve the robustness in return.

Semantic Metrics for Analysis of Software

NASA Technical Reports Server (NTRS)

Etzkorn, Letha H.; Cox, Glenn W.; Farrington, Phil; Utley, Dawn R.; Ghalston, Sampson; Stein, Cara

2005-01-01

A recently conceived suite of object-oriented software metrics focus is on semantic aspects of software, in contradistinction to traditional software metrics, which focus on syntactic aspects of software. Semantic metrics represent a more human-oriented view of software than do syntactic metrics. The semantic metrics of a given computer program are calculated by use of the output of a knowledge-based analysis of the program, and are substantially more representative of software quality and more readily comprehensible from a human perspective than are the syntactic metrics.

Engineering performance metrics

NASA Astrophysics Data System (ADS)

Delozier, R.; Snyder, N.

1993-03-01

Implementation of a Total Quality Management (TQM) approach to engineering work required the development of a system of metrics which would serve as a meaningful management tool for evaluating effectiveness in accomplishing project objectives and in achieving improved customer satisfaction. A team effort was chartered with the goal of developing a system of engineering performance metrics which would measure customer satisfaction, quality, cost effectiveness, and timeliness. The approach to developing this system involved normal systems design phases including, conceptual design, detailed design, implementation, and integration. The lessons teamed from this effort will be explored in this paper. These lessons learned may provide a starting point for other large engineering organizations seeking to institute a performance measurement system accomplishing project objectives and in achieving improved customer satisfaction. To facilitate this effort, a team was chartered to assist in the development of the metrics system. This team, consisting of customers and Engineering staff members, was utilized to ensure that the needs and views of the customers were considered in the development of performance measurements. The development of a system of metrics is no different than the development of any type of system. It includes the steps of defining performance measurement requirements, measurement process conceptual design, performance measurement and reporting system detailed design, and system implementation and integration.

Can state-of-the-art HVS-based objective image quality criteria be used for image reconstruction techniques based on ROI analysis?

NASA Astrophysics Data System (ADS)

Dostal, P.; Krasula, L.; Klima, M.

2012-06-01

Various image processing techniques in multimedia technology are optimized using visual attention feature of the human visual system. Spatial non-uniformity causes that different locations in an image are of different importance in terms of perception of the image. In other words, the perceived image quality depends mainly on the quality of important locations known as regions of interest. The performance of such techniques is measured by subjective evaluation or objective image quality criteria. Many state-of-the-art objective metrics are based on HVS properties; SSIM, MS-SSIM based on image structural information, VIF based on the information that human brain can ideally gain from the reference image or FSIM utilizing the low-level features to assign the different importance to each location in the image. But still none of these objective metrics utilize the analysis of regions of interest. We solve the question if these objective metrics can be used for effective evaluation of images reconstructed by processing techniques based on ROI analysis utilizing high-level features. In this paper authors show that the state-of-the-art objective metrics do not correlate well with subjective evaluation while the demosaicing based on ROI analysis is used for reconstruction. The ROI were computed from "ground truth" visual attention data. The algorithm combining two known demosaicing techniques on the basis of ROI location is proposed to reconstruct the ROI in fine quality while the rest of image is reconstructed with low quality. The color image reconstructed by this ROI approach was compared with selected demosaicing techniques by objective criteria and subjective testing. The qualitative comparison of the objective and subjective results indicates that the state-of-the-art objective metrics are still not suitable for evaluation image processing techniques based on ROI analysis and new criteria is demanded.

WE-AB-209-07: Explicit and Convex Optimization of Plan Quality Metrics in Intensity-Modulated Radiation Therapy Treatment Planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engberg, L; KTH Royal Institute of Technology, Stockholm; Eriksson, K

Purpose: To formulate objective functions of a multicriteria fluence map optimization model that correlate well with plan quality metrics, and to solve this multicriteria model by convex approximation. Methods: In this study, objectives of a multicriteria model are formulated to explicitly either minimize or maximize a dose-at-volume measure. Given the widespread agreement that dose-at-volume levels play important roles in plan quality assessment, these objectives correlate well with plan quality metrics. This is in contrast to the conventional objectives, which are to maximize clinical goal achievement by relating to deviations from given dose-at-volume thresholds: while balancing the new objectives means explicitlymore » balancing dose-at-volume levels, balancing the conventional objectives effectively means balancing deviations. Constituted by the inherently non-convex dose-at-volume measure, the new objectives are approximated by the convex mean-tail-dose measure (CVaR measure), yielding a convex approximation of the multicriteria model. Results: Advantages of using the convex approximation are investigated through juxtaposition with the conventional objectives in a computational study of two patient cases. Clinical goals of each case respectively point out three ROI dose-at-volume measures to be considered for plan quality assessment. This is translated in the convex approximation into minimizing three mean-tail-dose measures. Evaluations of the three ROI dose-at-volume measures on Pareto optimal plans are used to represent plan quality of the Pareto sets. Besides providing increased accuracy in terms of feasibility of solutions, the convex approximation generates Pareto sets with overall improved plan quality. In one case, the Pareto set generated by the convex approximation entirely dominates that generated with the conventional objectives. Conclusion: The initial computational study indicates that the convex approximation outperforms the conventional

Objective Quality and Intelligibility Prediction for Users of Assistive Listening Devices

PubMed Central

Falk, Tiago H.; Parsa, Vijay; Santos, João F.; Arehart, Kathryn; Hazrati, Oldooz; Huber, Rainer; Kates, James M.; Scollie, Susan

2015-01-01

This article presents an overview of twelve existing objective speech quality and intelligibility prediction tools. Two classes of algorithms are presented, namely intrusive and non-intrusive, with the former requiring the use of a reference signal, while the latter does not. Investigated metrics include both those developed for normal hearing listeners, as well as those tailored particularly for hearing impaired (HI) listeners who are users of assistive listening devices (i.e., hearing aids, HAs, and cochlear implants, CIs). Representative examples of those optimized for HI listeners include the speech-to-reverberation modulation energy ratio, tailored to hearing aids (SRMR-HA) and to cochlear implants (SRMR-CI); the modulation spectrum area (ModA); the hearing aid speech quality (HASQI) and perception indices (HASPI); and the PErception MOdel - hearing impairment quality (PEMO-Q-HI). The objective metrics are tested on three subjectively-rated speech datasets covering reverberation-alone, noise-alone, and reverberation-plus-noise degradation conditions, as well as degradations resultant from nonlinear frequency compression and different speech enhancement strategies. The advantages and limitations of each measure are highlighted and recommendations are given for suggested uses of the different tools under specific environmental and processing conditions. PMID:26052190

A management-oriented framework for selecting metrics used to assess habitat- and path-specific quality in spatially structured populations

USGS Publications Warehouse

Nicol, Sam; Wiederholt, Ruscena; Diffendorfer, James E.; Mattsson, Brady; Thogmartin, Wayne E.; Semmens, Darius J.; Laura Lopez-Hoffman,; Norris, Ryan

2016-01-01

Mobile species with complex spatial dynamics can be difficult to manage because their population distributions vary across space and time, and because the consequences of managing particular habitats are uncertain when evaluated at the level of the entire population. Metrics to assess the importance of habitats and pathways connecting habitats in a network are necessary to guide a variety of management decisions. Given the many metrics developed for spatially structured models, it can be challenging to select the most appropriate one for a particular decision. To guide the management of spatially structured populations, we define three classes of metrics describing habitat and pathway quality based on their data requirements (graph-based, occupancy-based, and demographic-based metrics) and synopsize the ecological literature relating to these classes. Applying the first steps of a formal decision-making approach (problem framing, objectives, and management actions), we assess the utility of metrics for particular types of management decisions. Our framework can help managers with problem framing, choosing metrics of habitat and pathway quality, and to elucidate the data needs for a particular metric. Our goal is to help managers to narrow the range of suitable metrics for a management project, and aid in decision-making to make the best use of limited resources.

A Survey of Health Management User Objectives Related to Diagnostic and Prognostic Metrics

NASA Technical Reports Server (NTRS)

Wheeler, Kevin R.; Kurtoglu, Tolga; Poll, Scott D.

2010-01-01

One of the most prominent technical challenges to effective deployment of health management systems is the vast difference in user objectives with respect to engineering development. In this paper, a detailed survey on the objectives of different users of health management systems is presented. These user objectives are then mapped to the metrics typically encountered in the development and testing of two main systems health management functions: diagnosis and prognosis. Using this mapping, the gaps between user goals and the metrics associated with diagnostics and prognostics are identified and presented with a collection of lessons learned from previous studies that include both industrial and military aerospace applications.

Development of quality metrics for ambulatory care in pediatric patients with tetralogy of Fallot.

PubMed

Villafane, Juan; Edwards, Thomas C; Diab, Karim A; Satou, Gary M; Saarel, Elizabeth; Lai, Wyman W; Serwer, Gerald A; Karpawich, Peter P; Cross, Russell; Schiff, Russell; Chowdhury, Devyani; Hougen, Thomas J

2017-12-01

The objective of this study was to develop quality metrics (QMs) relating to the ambulatory care of children after complete repair of tetralogy of Fallot (TOF). A workgroup team (WT) of pediatric cardiologists with expertise in all aspects of ambulatory cardiac management was formed at the request of the American College of Cardiology (ACC) and the Adult Congenital and Pediatric Cardiology Council (ACPC), to review published guidelines and consensus data relating to the ambulatory care of repaired TOF patients under the age of 18 years. A set of quality metrics (QMs) was proposed by the WT. The metrics went through a two-step evaluation process. In the first step, the RAND-UCLA modified Delphi methodology was employed and the metrics were voted on feasibility and validity by an expert panel. In the second step, QMs were put through an "open comments" process where feedback was provided by the ACPC members. The final QMs were approved by the ACPC council. The TOF WT formulated 9 QMs of which only 6 were submitted to the expert panel; 3 QMs passed the modified RAND-UCLA and went through the "open comments" process. Based on the feedback through the open comment process, only 1 metric was finally approved by the ACPC council. The ACPC Council was able to develop QM for ambulatory care of children with repaired TOF. These patients should have documented genetic testing for 22q11.2 deletion. However, lack of evidence in the literature made it a challenge to formulate other evidence-based QMs. © 2017 Wiley Periodicals, Inc.

New Quality Metrics for Web Search Results

NASA Astrophysics Data System (ADS)

Metaxas, Panagiotis Takis; Ivanova, Lilia; Mustafaraj, Eni

Web search results enjoy an increasing importance in our daily lives. But what can be said about their quality, especially when querying a controversial issue? The traditional information retrieval metrics of precision and recall do not provide much insight in the case of web information retrieval. In this paper we examine new ways of evaluating quality in search results: coverage and independence. We give examples on how these new metrics can be calculated and what their values reveal regarding the two major search engines, Google and Yahoo. We have found evidence of low coverage for commercial and medical controversial queries, and high coverage for a political query that is highly contested. Given the fact that search engines are unwilling to tune their search results manually, except in a few cases that have become the source of bad publicity, low coverage and independence reveal the efforts of dedicated groups to manipulate the search results.

Performance evaluation of no-reference image quality metrics for face biometric images

NASA Astrophysics Data System (ADS)

Liu, Xinwei; Pedersen, Marius; Charrier, Christophe; Bours, Patrick

2018-03-01

The accuracy of face recognition systems is significantly affected by the quality of face sample images. The recent established standardization proposed several important aspects for the assessment of face sample quality. There are many existing no-reference image quality metrics (IQMs) that are able to assess natural image quality by taking into account similar image-based quality attributes as introduced in the standardization. However, whether such metrics can assess face sample quality is rarely considered. We evaluate the performance of 13 selected no-reference IQMs on face biometrics. The experimental results show that several of them can assess face sample quality according to the system performance. We also analyze the strengths and weaknesses of different IQMs as well as why some of them failed to assess face sample quality. Retraining an original IQM by using face database can improve the performance of such a metric. In addition, the contribution of this paper can be used for the evaluation of IQMs on other biometric modalities; furthermore, it can be used for the development of multimodality biometric IQMs.

A no-reference image and video visual quality metric based on machine learning

NASA Astrophysics Data System (ADS)

Frantc, Vladimir; Voronin, Viacheslav; Semenishchev, Evgenii; Minkin, Maxim; Delov, Aliy

2018-04-01

The paper presents a novel visual quality metric for lossy compressed video quality assessment. High degree of correlation with subjective estimations of quality is due to using of a convolutional neural network trained on a large amount of pairs video sequence-subjective quality score. We demonstrate how our predicted no-reference quality metric correlates with qualitative opinion in a human observer study. Results are shown on the EVVQ dataset with comparison existing approaches.

A Perceptually Weighted Rank Correlation Indicator for Objective Image Quality Assessment

NASA Astrophysics Data System (ADS)

Wu, Qingbo; Li, Hongliang; Meng, Fanman; Ngan, King N.

2018-05-01

In the field of objective image quality assessment (IQA), the Spearman's $\\rho$ and Kendall's $\\tau$ are two most popular rank correlation indicators, which straightforwardly assign uniform weight to all quality levels and assume each pair of images are sortable. They are successful for measuring the average accuracy of an IQA metric in ranking multiple processed images. However, two important perceptual properties are ignored by them as well. Firstly, the sorting accuracy (SA) of high quality images are usually more important than the poor quality ones in many real world applications, where only the top-ranked images would be pushed to the users. Secondly, due to the subjective uncertainty in making judgement, two perceptually similar images are usually hardly sortable, whose ranks do not contribute to the evaluation of an IQA metric. To more accurately compare different IQA algorithms, we explore a perceptually weighted rank correlation indicator in this paper, which rewards the capability of correctly ranking high quality images, and suppresses the attention towards insensitive rank mistakes. More specifically, we focus on activating `valid' pairwise comparison towards image quality, whose difference exceeds a given sensory threshold (ST). Meanwhile, each image pair is assigned an unique weight, which is determined by both the quality level and rank deviation. By modifying the perception threshold, we can illustrate the sorting accuracy with a more sophisticated SA-ST curve, rather than a single rank correlation coefficient. The proposed indicator offers a new insight for interpreting visual perception behaviors. Furthermore, the applicability of our indicator is validated in recommending robust IQA metrics for both the degraded and enhanced image data.

National Quality Forum Colon Cancer Quality Metric Performance: How Are Hospitals Measuring Up?

PubMed

Mason, Meredith C; Chang, George J; Petersen, Laura A; Sada, Yvonne H; Tran Cao, Hop S; Chai, Christy; Berger, David H; Massarweh, Nader N

2017-12-01

To evaluate the impact of care at high-performing hospitals on the National Quality Forum (NQF) colon cancer metrics. The NQF endorses evaluating ≥12 lymph nodes (LNs), adjuvant chemotherapy (AC) for stage III patients, and AC within 4 months of diagnosis as colon cancer quality indicators. Data on hospital-level metric performance and the association with survival are unclear. Retrospective cohort study of 218,186 patients with resected stage I to III colon cancer in the National Cancer Data Base (2004-2012). High-performing hospitals (>75% achievement) were identified by the proportion of patients achieving each measure. The association between hospital performance and survival was evaluated using Cox shared frailty modeling. Only hospital LN performance improved (15.8% in 2004 vs 80.7% in 2012; trend test, P < 0.001), with 45.9% of hospitals performing well on all 3 measures concurrently in the most recent study year. Overall, 5-year survival was 75.0%, 72.3%, 72.5%, and 69.5% for those treated at hospitals with high performance on 3, 2, 1, and 0 metrics, respectively (log-rank, P < 0.001). Care at hospitals with high metric performance was associated with lower risk of death in a dose-response fashion [0 metrics, reference; 1, hazard ratio (HR) 0.96 (0.89-1.03); 2, HR 0.92 (0.87-0.98); 3, HR 0.85 (0.80-0.90); 2 vs 1, HR 0.96 (0.91-1.01); 3 vs 1, HR 0.89 (0.84-0.93); 3 vs 2, HR 0.95 (0.89-0.95)]. Performance on metrics in combination was associated with lower risk of death [LN + AC, HR 0.86 (0.78-0.95); AC + timely AC, HR 0.92 (0.87-0.98); LN + AC + timely AC, HR 0.85 (0.80-0.90)], whereas individual measures were not [LN, HR 0.95 (0.88-1.04); AC, HR 0.95 (0.87-1.05)]. Less than half of hospitals perform well on these NQF colon cancer metrics concurrently, and high performance on individual measures is not associated with improved survival. Quality improvement efforts should shift focus from individual measures to defining composite measures

On the performance of metrics to predict quality in point cloud representations

NASA Astrophysics Data System (ADS)

Alexiou, Evangelos; Ebrahimi, Touradj

2017-09-01

Point clouds are a promising alternative for immersive representation of visual contents. Recently, an increased interest has been observed in the acquisition, processing and rendering of this modality. Although subjective and objective evaluations are critical in order to assess the visual quality of media content, they still remain open problems for point cloud representation. In this paper we focus our efforts on subjective quality assessment of point cloud geometry, subject to typical types of impairments such as noise corruption and compression-like distortions. In particular, we propose a subjective methodology that is closer to real-life scenarios of point cloud visualization. The performance of the state-of-the-art objective metrics is assessed by considering the subjective scores as the ground truth. Moreover, we investigate the impact of adopting different test methodologies by comparing them. Advantages and drawbacks of every approach are reported, based on statistical analysis. The results and conclusions of this work provide useful insights that could be considered in future experimentation.

Objective assessment based on motion-related metrics and technical performance in laparoscopic suturing.

PubMed

Sánchez-Margallo, Juan A; Sánchez-Margallo, Francisco M; Oropesa, Ignacio; Enciso, Silvia; Gómez, Enrique J

2017-02-01

The aim of this study is to present the construct and concurrent validity of a motion-tracking method of laparoscopic instruments based on an optical pose tracker and determine its feasibility as an objective assessment tool of psychomotor skills during laparoscopic suturing. A group of novice ([Formula: see text] laparoscopic procedures), intermediate (11-100 laparoscopic procedures) and experienced ([Formula: see text] laparoscopic procedures) surgeons performed three intracorporeal sutures on an ex vivo porcine stomach. Motion analysis metrics were recorded using the proposed tracking method, which employs an optical pose tracker to determine the laparoscopic instruments' position. Construct validation was measured for all 10 metrics across the three groups and between pairs of groups. Concurrent validation was measured against a previously validated suturing checklist. Checklists were completed by two independent surgeons over blinded video recordings of the task. Eighteen novices, 15 intermediates and 11 experienced surgeons took part in this study. Execution time and path length travelled by the laparoscopic dissector presented construct validity. Experienced surgeons required significantly less time ([Formula: see text]), travelled less distance using both laparoscopic instruments ([Formula: see text]) and made more efficient use of the work space ([Formula: see text]) compared with novice and intermediate surgeons. Concurrent validation showed strong correlation between both the execution time and path length and the checklist score ([Formula: see text] and [Formula: see text], [Formula: see text]). The suturing performance was successfully assessed by the motion analysis method. Construct and concurrent validity of the motion-based assessment method has been demonstrated for the execution time and path length metrics. This study demonstrates the efficacy of the presented method for objective evaluation of psychomotor skills in laparoscopic suturing

Does objective quality of physicians correlate with patient satisfaction measured by Hospital Compare metrics in New York State?

PubMed Central

Bekelis, Kimon; Missios, Symeon; MacKenzie, Todd A.; O’Shaughnessy, Patrick M.

2017-01-01

Background It is unclear whether publicly reported benchmarks correlate with the quality of physicians and institutions. We investigated the association of patient satisfaction measures from a public reporting platform with the performance of neurosurgeons in New York State. Methods We performed a cohort study involving patients undergoing neurosurgical operations from 2009–2013, who were registered in the Statewide Planning and Research Cooperative System (SPARCS) database. This cohort was merged with publicly available data from the CMS Hospital Compare website. A propensity adjusted regression analysis was used to investigate the association of patient satisfaction metrics with neurosurgeon quality, as measured by their individual rate of mortality and average length-of-stay (LOS). Results Overall, 166,365 patients underwent neurosurgical procedures during the study. Using a propensity adjusted multivariable regression analysis we demonstrated that undergoing neurosurgical operations in hospitals with a greater percentage of patient-assigned “high” score were associated with higher chance of being treated by a physician with superior performance in terms of mortality (OR 1.90; 95% CI, 1.86 to 1.95), and a higher chance of being treated by a physician with superior performance in terms of length-of-stay (LOS) (OR 1.24; 95% CI, 1.21 to 1.27). Similar associations were identified for hospitals with a higher percentage of patients, who claimed they would recommend these institutions to others. Conclusions Merging a comprehensive all-payer cohort of neurosurgery patients in New York State with data from the CMS Hospital Compare website, we observed an association of superior hospital-level patient satisfaction measures with the objective performance of individual neurosurgeons in the corresponding hospitals. PMID:28456743

Measuring Sustainability: Deriving Metrics From Objectives (Presentation)

EPA Science Inventory

The definition of 'sustain', to keep in existence, provides some insight into the metrics that are required to measure sustainability and adequately respond to assure sustainability. Keeping something in existence implies temporal and spatial contexts and requires metrics that g...

Development of Quality Metrics in Ambulatory Pediatric Cardiology.

PubMed

Chowdhury, Devyani; Gurvitz, Michelle; Marelli, Ariane; Anderson, Jeffrey; Baker-Smith, Carissa; Diab, Karim A; Edwards, Thomas C; Hougen, Tom; Jedeikin, Roy; Johnson, Jonathan N; Karpawich, Peter; Lai, Wyman; Lu, Jimmy C; Mitchell, Stephanie; Newburger, Jane W; Penny, Daniel J; Portman, Michael A; Satou, Gary; Teitel, David; Villafane, Juan; Williams, Roberta; Jenkins, Kathy

2017-02-07

The American College of Cardiology Adult Congenital and Pediatric Cardiology (ACPC) Section had attempted to create quality metrics (QM) for ambulatory pediatric practice, but limited evidence made the process difficult. The ACPC sought to develop QMs for ambulatory pediatric cardiology practice. Five areas of interest were identified, and QMs were developed in a 2-step review process. In the first step, an expert panel, using the modified RAND-UCLA methodology, rated each QM for feasibility and validity. The second step sought input from ACPC Section members; final approval was by a vote of the ACPC Council. Work groups proposed a total of 44 QMs. Thirty-one metrics passed the RAND process and, after the open comment period, the ACPC council approved 18 metrics. The project resulted in successful development of QMs in ambulatory pediatric cardiology for a range of ambulatory domains. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Comparison of macroinvertebrate-derived stream quality metrics between snag and riffle habitats

USGS Publications Warehouse

Stepenuck, K.F.; Crunkilton, R.L.; Bozek, Michael A.; Wang, L.

2008-01-01

We compared benthic macroinvertebrate assemblage structure at snag and riffle habitats in 43 Wisconsin streams across a range of watershed urbanization using a variety of stream quality metrics. Discriminant analysis indicated that dominant taxa at riffles and snags differed; Hydropsychid caddisflies (Hydropsyche betteni and Cheumatopsyche spp.) and elmid beetles (Optioservus spp. and Stenemlis spp.) typified riffles, whereas isopods (Asellus intermedius) and amphipods (Hyalella azteca and Gammarus pseudolimnaeus) predominated in snags. Analysis of covariance indicated that samples from snag and riffle habitats differed significantly in their response to the urbanization gradient for the Hilsenhoff biotic index (BI), Shannon's diversity index, and percent of filterers, shredders, and pollution intolerant Ephemeroptera, Plecoptera, and Trichoptera (EPT) at each stream site (p ??? 0.10). These differences suggest that although macroinvertebrate assemblages present in either habitat type are sensitive to detecting the effects of urbanization, metrics derived from different habitats should not be intermixed when assessing stream quality through biomonitoring. This can be a limitation to resource managers who wish to compare water quality among streams where the same habitat type is not available at all stream locations, or where a specific habitat type (i.e., a riffle) is required to determine a metric value (i.e., BI). To account for differences in stream quality at sites lacking riffle habitat, snag-derived metric values can be adjusted based on those obtained from riffles that have been exposed to the same level of urbanization. Comparison of nonlinear regression equations that related stream quality metric values from the two habitat types to percent watershed urbanization indicated that snag habitats had on average 30.2 fewer percent EPT individuals, a lower diversity index value than riffles, and a BI value of 0.29 greater than riffles. ?? 2008 American Water

The Nutrient Balance Concept: A New Quality Metric for Composite Meals and Diets

PubMed Central

Fern, Edward B; Watzke, Heribert; Barclay, Denis V.; Roulin, Anne; Drewnowski, Adam

2015-01-01

Background Combinations of foods that provide suitable levels of nutrients and energy are required for optimum health. Currently, however, it is difficult to define numerically what are ‘suitable levels’. Objective To develop new metrics based on energy considerations—the Nutrient Balance Concept (NBC)—for assessing overall nutrition quality when combining foods and meals. Method The NBC was developed using the USDA Food Composition Database (Release 27) and illustrated with their MyPlate 7-day sample menus for a 2000 calorie food pattern. The NBC concept is centered on three specific metrics for a given food, meal or diet—a Qualifying Index (QI), a Disqualifying Index (DI) and a Nutrient Balance (NB). The QI and DI were determined, respectively, from the content of 27 essential nutrients and 6 nutrients associated with negative health outcomes. The third metric, the Nutrient Balance (NB), was derived from the Qualifying Index (QI) and provided key information on the relative content of qualifying nutrients in the food. Because the Qualifying and Disqualifying Indices (QI and DI) were standardized to energy content, both become constants for a given food/meal/diet and a particular consumer age group, making it possible to develop algorithms for predicting nutrition quality when combining different foods. Results Combining different foods into composite meals and daily diets led to improved nutrition quality as seen by QI values closer to unity (indicating nutrient density was better equilibrated with energy density), DI values below 1.0 (denoting an acceptable level of consumption of disqualifying nutrients) and increased NB values (signifying complementarity of foods and better provision of qualifying nutrients). Conclusion The Nutrient Balance Concept (NBC) represents a new approach to nutrient profiling and the first step in the progression from the nutrient evaluation of individual foods to that of multiple foods in the context of meals and total

Automatic red eye correction and its quality metric

NASA Astrophysics Data System (ADS)

Safonov, Ilia V.; Rychagov, Michael N.; Kang, KiMin; Kim, Sang Ho

2008-01-01

The red eye artifacts are troublesome defect of amateur photos. Correction of red eyes during printing without user intervention and making photos more pleasant for an observer are important tasks. The novel efficient technique of automatic correction of red eyes aimed for photo printers is proposed. This algorithm is independent from face orientation and capable to detect paired red eyes as well as single red eyes. The approach is based on application of 3D tables with typicalness levels for red eyes and human skin tones and directional edge detection filters for processing of redness image. Machine learning is applied for feature selection. For classification of red eye regions a cascade of classifiers including Gentle AdaBoost committee from Classification and Regression Trees (CART) is applied. Retouching stage includes desaturation, darkening and blending with initial image. Several versions of approach implementation using trade-off between detection and correction quality, processing time, memory volume are possible. The numeric quality criterion of automatic red eye correction is proposed. This quality metric is constructed by applying Analytic Hierarchy Process (AHP) for consumer opinions about correction outcomes. Proposed numeric metric helped to choose algorithm parameters via optimization procedure. Experimental results demonstrate high accuracy and efficiency of the proposed algorithm in comparison with existing solutions.

The software product assurance metrics study: JPL's software systems quality and productivity

NASA Technical Reports Server (NTRS)

Bush, Marilyn W.

1989-01-01

The findings are reported of the Jet Propulsion Laboratory (JPL)/Software Product Assurance (SPA) Metrics Study, conducted as part of a larger JPL effort to improve software quality and productivity. Until recently, no comprehensive data had been assembled on how JPL manages and develops software-intensive systems. The first objective was to collect data on software development from as many projects and for as many years as possible. Results from five projects are discussed. These results reflect 15 years of JPL software development, representing over 100 data points (systems and subsystems), over a third of a billion dollars, over four million lines of code and 28,000 person months. Analysis of this data provides a benchmark for gauging the effectiveness of past, present and future software development work. In addition, the study is meant to encourage projects to record existing metrics data and to gather future data. The SPA long term goal is to integrate the collection of historical data and ongoing project data with future project estimations.

Sigma metrics as a tool for evaluating the performance of internal quality control in a clinical chemistry laboratory

PubMed Central

Kumar, B. Vinodh; Mohan, Thuthi

2018-01-01

OBJECTIVE: Six Sigma is one of the most popular quality management system tools employed for process improvement. The Six Sigma methods are usually applied when the outcome of the process can be measured. This study was done to assess the performance of individual biochemical parameters on a Sigma Scale by calculating the sigma metrics for individual parameters and to follow the Westgard guidelines for appropriate Westgard rules and levels of internal quality control (IQC) that needs to be processed to improve target analyte performance based on the sigma metrics. MATERIALS AND METHODS: This is a retrospective study, and data required for the study were extracted between July 2015 and June 2016 from a Secondary Care Government Hospital, Chennai. The data obtained for the study are IQC - coefficient of variation percentage and External Quality Assurance Scheme (EQAS) - Bias% for 16 biochemical parameters. RESULTS: For the level 1 IQC, four analytes (alkaline phosphatase, magnesium, triglyceride, and high-density lipoprotein-cholesterol) showed an ideal performance of ≥6 sigma level, five analytes (urea, total bilirubin, albumin, cholesterol, and potassium) showed an average performance of <3 sigma level and for level 2 IQCs, same four analytes of level 1 showed a performance of ≥6 sigma level, and four analytes (urea, albumin, cholesterol, and potassium) showed an average performance of <3 sigma level. For all analytes <6 sigma level, the quality goal index (QGI) was <0.8 indicating the area requiring improvement to be imprecision except cholesterol whose QGI >1.2 indicated inaccuracy. CONCLUSION: This study shows that sigma metrics is a good quality tool to assess the analytical performance of a clinical chemistry laboratory. Thus, sigma metric analysis provides a benchmark for the laboratory to design a protocol for IQC, address poor assay performance, and assess the efficiency of existing laboratory processes. PMID:29692587

Objective Quality Assessment for Color-to-Gray Image Conversion.

PubMed

Ma, Kede; Zhao, Tiesong; Zeng, Kai; Wang, Zhou

2015-12-01

Color-to-gray (C2G) image conversion is the process of transforming a color image into a grayscale one. Despite its wide usage in real-world applications, little work has been dedicated to compare the performance of C2G conversion algorithms. Subjective evaluation is reliable but is also inconvenient and time consuming. Here, we make one of the first attempts to develop an objective quality model that automatically predicts the perceived quality of C2G converted images. Inspired by the philosophy of the structural similarity index, we propose a C2G structural similarity (C2G-SSIM) index, which evaluates the luminance, contrast, and structure similarities between the reference color image and the C2G converted image. The three components are then combined depending on image type to yield an overall quality measure. Experimental results show that the proposed C2G-SSIM index has close agreement with subjective rankings and significantly outperforms existing objective quality metrics for C2G conversion. To explore the potentials of C2G-SSIM, we further demonstrate its use in two applications: 1) automatic parameter tuning for C2G conversion algorithms and 2) adaptive fusion of C2G converted images.

Multivariate Analyses of Quality Metrics for Crystal Structures in the PDB Archive.

PubMed

Shao, Chenghua; Yang, Huanwang; Westbrook, John D; Young, Jasmine Y; Zardecki, Christine; Burley, Stephen K

2017-03-07

Following deployment of an augmented validation system by the Worldwide Protein Data Bank (wwPDB) partnership, the quality of crystal structures entering the PDB has improved. Of significance are improvements in quality measures now prominently displayed in the wwPDB validation report. Comparisons of PDB depositions made before and after introduction of the new reporting system show improvements in quality measures relating to pairwise atom-atom clashes, side-chain torsion angle rotamers, and local agreement between the atomic coordinate structure model and experimental electron density data. These improvements are largely independent of resolution limit and sample molecular weight. No significant improvement in the quality of associated ligands was observed. Principal component analysis revealed that structure quality could be summarized with three measures (Rfree, real-space R factor Z score, and a combined molecular geometry quality metric), which can in turn be reduced to a single overall quality metric readily interpretable by all PDB archive users. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of Two Models to Set and Evaluate Quality Targets for HbA1c: Biological Variation and Sigma-metrics

PubMed Central

Weykamp, Cas; John, Garry; Gillery, Philippe; English, Emma; Ji, Linong; Lenters-Westra, Erna; Little, Randie R.; Roglic, Gojka; Sacks, David B.; Takei, Izumi

2016-01-01

Background A major objective of the IFCC Task Force on implementation of HbA1c standardization is to develop a model to define quality targets for HbA1c. Methods Two generic models, the Biological Variation and Sigma-metrics model, are investigated. Variables in the models were selected for HbA1c and data of EQA/PT programs were used to evaluate the suitability of the models to set and evaluate quality targets within and between laboratories. Results In the biological variation model 48% of individual laboratories and none of the 26 instrument groups met the minimum performance criterion. In the Sigma-metrics model, with a total allowable error (TAE) set at 5 mmol/mol (0.46% NGSP) 77% of the individual laboratories and 12 of 26 instrument groups met the 2 sigma criterion. Conclusion The Biological Variation and Sigma-metrics model were demonstrated to be suitable for setting and evaluating quality targets within and between laboratories. The Sigma-metrics model is more flexible as both the TAE and the risk of failure can be adjusted to requirements related to e.g. use for diagnosis/monitoring or requirements of (inter)national authorities. With the aim of reaching international consensus on advice regarding quality targets for HbA1c, the Task Force suggests the Sigma-metrics model as the model of choice with default values of 5 mmol/mol (0.46%) for TAE, and risk levels of 2 and 4 sigma for routine laboratories and laboratories performing clinical trials, respectively. These goals should serve as a starting point for discussion with international stakeholders in the field of diabetes. PMID:25737535

DATA QUALITY OBJECTIVES AND MEASUREMENT QUALITY OBJECTIVES FOR RESEARCH PROJECTS

EPA Science Inventory

The paper provides assistance with systematic planning using measurement quality objectives to those working on research projects. These performance criteria are more familiar to researchers than data quality objectives because they are more closely associated with the measuremen...

Feasibility of and Rationale for the Collection of Orthopaedic Trauma Surgery Quality of Care Metrics.

PubMed

Miller, Anna N; Kozar, Rosemary; Wolinsky, Philip

2017-06-01

Reproducible metrics are needed to evaluate the delivery of orthopaedic trauma care, national care, norms, and outliers. The American College of Surgeons (ACS) is uniquely positioned to collect and evaluate the data needed to evaluate orthopaedic trauma care via the Committee on Trauma and the Trauma Quality Improvement Project. We evaluated the first quality metrics the ACS has collected for orthopaedic trauma surgery to determine whether these metrics can be appropriately collected with accuracy and completeness. The metrics include the time to administration of the first dose of antibiotics for open fractures, the time to surgical irrigation and débridement of open tibial fractures, and the percentage of patients who undergo stabilization of femoral fractures at trauma centers nationwide. These metrics were analyzed to evaluate for variances in the delivery of orthopaedic care across the country. The data showed wide variances for all metrics, and many centers had incomplete ability to collect the orthopaedic trauma care metrics. There was a large variability in the results of the metrics collected among different trauma center levels, as well as among centers of a particular level. The ACS has successfully begun tracking orthopaedic trauma care performance measures, which will help inform reevaluation of the goals and continued work on data collection and improvement of patient care. Future areas of research may link these performance measures with patient outcomes, such as long-term tracking, to assess nonunion and function. This information can provide insight into center performance and its effect on patient outcomes. The ACS was able to successfully collect and evaluate the data for three metrics used to assess the quality of orthopaedic trauma care. However, additional research is needed to determine whether these metrics are suitable for evaluating orthopaedic trauma care and cutoff values for each metric.

The Assignment of Scale to Object-Oriented Software Measures

NASA Technical Reports Server (NTRS)

Neal, Ralph D.; Weistroffer, H. Roland; Coppins, Richard J.

1997-01-01

In order to improve productivity (and quality), measurement of specific aspects of software has become imperative. As object oriented programming languages have become more widely used, metrics designed specifically for object-oriented software are required. Recently a large number of new metrics for object- oriented software has appeared in the literature. Unfortunately, many of these proposed metrics have not been validated to measure what they purport to measure. In this paper fifty (50) of these metrics are analyzed.

A Locally Weighted Fixation Density-Based Metric for Assessing the Quality of Visual Saliency Predictions

NASA Astrophysics Data System (ADS)

Gide, Milind S.; Karam, Lina J.

2016-08-01

With the increased focus on visual attention (VA) in the last decade, a large number of computational visual saliency methods have been developed over the past few years. These models are traditionally evaluated by using performance evaluation metrics that quantify the match between predicted saliency and fixation data obtained from eye-tracking experiments on human observers. Though a considerable number of such metrics have been proposed in the literature, there are notable problems in them. In this work, we discuss shortcomings in existing metrics through illustrative examples and propose a new metric that uses local weights based on fixation density which overcomes these flaws. To compare the performance of our proposed metric at assessing the quality of saliency prediction with other existing metrics, we construct a ground-truth subjective database in which saliency maps obtained from 17 different VA models are evaluated by 16 human observers on a 5-point categorical scale in terms of their visual resemblance with corresponding ground-truth fixation density maps obtained from eye-tracking data. The metrics are evaluated by correlating metric scores with the human subjective ratings. The correlation results show that the proposed evaluation metric outperforms all other popular existing metrics. Additionally, the constructed database and corresponding subjective ratings provide an insight into which of the existing metrics and future metrics are better at estimating the quality of saliency prediction and can be used as a benchmark.

Modeling the interannual variability of microbial quality metrics of irrigation water in a Pennsylvania stream.

PubMed

Hong, Eun-Mi; Shelton, Daniel; Pachepsky, Yakov A; Nam, Won-Ho; Coppock, Cary; Muirhead, Richard

2017-02-01

Knowledge of the microbial quality of irrigation waters is extremely limited. For this reason, the US FDA has promulgated the Produce Rule, mandating the testing of irrigation water sources for many farms. The rule requires the collection and analysis of at least 20 water samples over two to four years to adequately evaluate the quality of water intended for produce irrigation. The objective of this work was to evaluate the effect of interannual weather variability on surface water microbial quality. We used the Soil and Water Assessment Tool model to simulate E. coli concentrations in the Little Cove Creek; this is a perennial creek located in an agricultural watershed in south-eastern Pennsylvania. The model performance was evaluated using the US FDA regulatory microbial water quality metrics of geometric mean (GM) and the statistical threshold value (STV). Using the 90-year time series of weather observations, we simulated and randomly sampled the time series of E. coli concentrations. We found that weather conditions of a specific year may strongly affect the evaluation of microbial quality and that the long-term assessment of microbial water quality may be quite different from the evaluation based on short-term observations. The variations in microbial concentrations and water quality metrics were affected by location, wetness of the hydrological years, and seasonality, with 15.7-70.1% of samples exceeding the regulatory threshold. The results of this work demonstrate the value of using modeling to design and evaluate monitoring protocols to assess the microbial quality of water used for produce irrigation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Guiding principles and checklist for population-based quality metrics.

PubMed

Krishnan, Mahesh; Brunelli, Steven M; Maddux, Franklin W; Parker, Thomas F; Johnson, Douglas; Nissenson, Allen R; Collins, Allan; Lacson, Eduardo

2014-06-06

The Centers for Medicare and Medicaid Services oversees the ESRD Quality Incentive Program to ensure that the highest quality of health care is provided by outpatient dialysis facilities that treat patients with ESRD. To that end, Centers for Medicare and Medicaid Services uses clinical performance measures to evaluate quality of care under a pay-for-performance or value-based purchasing model. Now more than ever, the ESRD therapeutic area serves as the vanguard of health care delivery. By translating medical evidence into clinical performance measures, the ESRD Prospective Payment System became the first disease-specific sector using the pay-for-performance model. A major challenge for the creation and implementation of clinical performance measures is the adjustments that are necessary to transition from taking care of individual patients to managing the care of patient populations. The National Quality Forum and others have developed effective and appropriate population-based clinical performance measures quality metrics that can be aggregated at the physician, hospital, dialysis facility, nursing home, or surgery center level. Clinical performance measures considered for endorsement by the National Quality Forum are evaluated using five key criteria: evidence, performance gap, and priority (impact); reliability; validity; feasibility; and usability and use. We have developed a checklist of special considerations for clinical performance measure development according to these National Quality Forum criteria. Although the checklist is focused on ESRD, it could also have broad application to chronic disease states, where health care delivery organizations seek to enhance quality, safety, and efficiency of their services. Clinical performance measures are likely to become the norm for tracking performance for health care insurers. Thus, it is critical that the methodologies used to develop such metrics serve the payer and the provider and most importantly, reflect

Guiding Principles and Checklist for Population-Based Quality Metrics

PubMed Central

Brunelli, Steven M.; Maddux, Franklin W.; Parker, Thomas F.; Johnson, Douglas; Nissenson, Allen R.; Collins, Allan; Lacson, Eduardo

2014-01-01

The Centers for Medicare and Medicaid Services oversees the ESRD Quality Incentive Program to ensure that the highest quality of health care is provided by outpatient dialysis facilities that treat patients with ESRD. To that end, Centers for Medicare and Medicaid Services uses clinical performance measures to evaluate quality of care under a pay-for-performance or value-based purchasing model. Now more than ever, the ESRD therapeutic area serves as the vanguard of health care delivery. By translating medical evidence into clinical performance measures, the ESRD Prospective Payment System became the first disease-specific sector using the pay-for-performance model. A major challenge for the creation and implementation of clinical performance measures is the adjustments that are necessary to transition from taking care of individual patients to managing the care of patient populations. The National Quality Forum and others have developed effective and appropriate population-based clinical performance measures quality metrics that can be aggregated at the physician, hospital, dialysis facility, nursing home, or surgery center level. Clinical performance measures considered for endorsement by the National Quality Forum are evaluated using five key criteria: evidence, performance gap, and priority (impact); reliability; validity; feasibility; and usability and use. We have developed a checklist of special considerations for clinical performance measure development according to these National Quality Forum criteria. Although the checklist is focused on ESRD, it could also have broad application to chronic disease states, where health care delivery organizations seek to enhance quality, safety, and efficiency of their services. Clinical performance measures are likely to become the norm for tracking performance for health care insurers. Thus, it is critical that the methodologies used to develop such metrics serve the payer and the provider and most importantly, reflect

A novel no-reference objective stereoscopic video quality assessment method based on visual saliency analysis

NASA Astrophysics Data System (ADS)

Yang, Xinyan; Zhao, Wei; Ye, Long; Zhang, Qin

2017-07-01

This paper proposes a no-reference objective stereoscopic video quality assessment method with the motivation that making the effect of objective experiments close to that of subjective way. We believe that the image regions with different visual salient degree should not have the same weights when designing an assessment metric. Therefore, we firstly use GBVS algorithm to each frame pairs and separate both the left and right viewing images into the regions with strong, general and week saliency. Besides, local feature information like blockiness, zero-crossing and depth are extracted and combined with a mathematical model to calculate a quality assessment score. Regions with different salient degree are assigned with different weights in the mathematical model. Experiment results demonstrate the superiority of our method compared with the existed state-of-the-art no-reference objective Stereoscopic video quality assessment methods.

APPLICATION OF DATA QUALITY OBJECTIVES AND MEASUREMENT QUALITY OBJECTIVES TO RESEARCH PROJECTS

EPA Science Inventory

The paper assists systematic planning for research projects. It presents planning concepts in terms that have some utility for researchers. For example, measurement quality objectives are more familiar to researchers than data quality objectives because these quality criteria are...

Usability Evaluations of a Wearable Inertial Sensing System and Quality of Movement Metrics for Stroke Survivors by Care Professionals.

PubMed

Klaassen, Bart; van Beijnum, Bert-Jan F; Held, Jeremia P; Reenalda, Jasper; van Meulen, Fokke B; Veltink, Peter H; Hermens, Hermie J

2017-01-01

Inertial motion capture systems are used in many applications such as measuring the movement quality in stroke survivors. The absence of clinical effectiveness and usability evidence in these assistive technologies into rehabilitation has delayed the transition of research into clinical practice. Recently, a new inertial motion capture system was developed in a project, called INTERACTION, to objectively measure the quality of movement (QoM) in stroke survivors during daily-life activity. With INTERACTION, we are to be able to investigate into what happens with patients after discharge from the hospital. Resulting QoM metrics, where a metric is defined as a measure of some property, are subsequently presented to care professionals. Metrics include for example: reaching distance, walking speed, and hand distribution plots. The latter shows a density plot of the hand position in the transversal plane. The objective of this study is to investigate the opinions of care professionals in using these metrics obtained from INTERACTION and its usability. By means of a semi-structured interview, guided by a presentation, presenting two patient reports. Each report includes several QoM metric (like reaching distance, hand position density plots, shoulder abduction) results obtained during daily-life measurements and in clinic and were evaluated by care professionals not related to the project. The results were compared with care professionals involved within the INTERACTION project. Furthermore, two questionnaires (5-point Likert and open questionnaire) were handed over to rate the usability of the metrics and to investigate if they would like such a system in their clinic. Eleven interviews were conducted, where each interview included either two or three care professionals as a group, in Switzerland and The Netherlands. Evaluation of the case reports (CRs) by participants and INTERACTION members showed a high correlation for both lower and upper extremity metrics

Beyond metrics? Utilizing 'soft intelligence' for healthcare quality and safety.

PubMed

Martin, Graham P; McKee, Lorna; Dixon-Woods, Mary

2015-10-01

Formal metrics for monitoring the quality and safety of healthcare have a valuable role, but may not, by themselves, yield full insight into the range of fallibilities in organizations. 'Soft intelligence' is usefully understood as the processes and behaviours associated with seeking and interpreting soft data-of the kind that evade easy capture, straightforward classification and simple quantification-to produce forms of knowledge that can provide the basis for intervention. With the aim of examining current and potential practice in relation to soft intelligence, we conducted and analysed 107 in-depth qualitative interviews with senior leaders, including managers and clinicians, involved in healthcare quality and safety in the English National Health Service. We found that participants were in little doubt about the value of softer forms of data, especially for their role in revealing troubling issues that might be obscured by conventional metrics. Their struggles lay in how to access softer data and turn them into a useful form of knowing. Some of the dominant approaches they used risked replicating the limitations of hard, quantitative data. They relied on processes of aggregation and triangulation that prioritised reliability, or on instrumental use of soft data to animate the metrics. The unpredictable, untameable, spontaneous quality of soft data could be lost in efforts to systematize their collection and interpretation to render them more tractable. A more challenging but potentially rewarding approach involved processes and behaviours aimed at disrupting taken-for-granted assumptions about quality, safety, and organizational performance. This approach, which explicitly values the seeking out and the hearing of multiple voices, is consistent with conceptual frameworks of organizational sensemaking and dialogical understandings of knowledge. Using soft intelligence this way can be challenging and discomfiting, but may offer a critical defence against the

Metrics for the Evaluation the Utility of Air Quality Forecasting

NASA Astrophysics Data System (ADS)

Sumo, T. M.; Stockwell, W. R.

2013-12-01

Global warming is expected to lead to higher levels of air pollution and therefore the forecasting of both long-term and daily air quality is an important component for the assessment of the costs of climate change and its impact on human health. Some of the risks associated with poor air quality days (where the Air Pollution Index is greater than 100), include hospital visits and mortality. Accurate air quality forecasting has the potential to allow sensitive groups to take appropriate precautions. This research builds metrics for evaluating the utility of air quality forecasting in terms of its potential impacts. Our analysis of air quality models focuses on the Washington, DC/Baltimore, MD region over the summertime ozone seasons between 2010 and 2012. The metrics that are relevant to our analysis include: (1) The number of times that a high ozone or particulate matter (PM) episode is correctly forecasted, (2) the number of times that high ozone or PM episode is forecasted when it does not occur and (3) the number of times when the air quality forecast predicts a cleaner air episode when the air was observed to have high ozone or PM. Our evaluation of the performance of air quality forecasts include those forecasts of ozone and particulate matter and data available from the U.S. Environmental Protection Agency (EPA)'s AIRNOW. We also examined observational ozone and particulate matter data available from Clean Air Partners. Overall the forecast models perform well for our region and time interval.

Evaluation of image deblurring methods via a classification metric

NASA Astrophysics Data System (ADS)

Perrone, Daniele; Humphreys, David; Lamb, Robert A.; Favaro, Paolo

2012-09-01

The performance of single image deblurring algorithms is typically evaluated via a certain discrepancy measure between the reconstructed image and the ideal sharp image. The choice of metric, however, has been a source of debate and has also led to alternative metrics based on human visual perception. While fixed metrics may fail to capture some small but visible artifacts, perception-based metrics may favor reconstructions with artifacts that are visually pleasant. To overcome these limitations, we propose to assess the quality of reconstructed images via a task-driven metric. In this paper we consider object classification as the task and therefore use the rate of classification as the metric to measure deblurring performance. In our evaluation we use data with different types of blur in two cases: Optical Character Recognition (OCR), where the goal is to recognise characters in a black and white image, and object classification with no restrictions on pose, illumination and orientation. Finally, we show how off-the-shelf classification algorithms benefit from working with deblurred images.

Beyond metrics? Utilizing ‘soft intelligence’ for healthcare quality and safety

PubMed Central

Martin, Graham P.; McKee, Lorna; Dixon-Woods, Mary

2015-01-01

Formal metrics for monitoring the quality and safety of healthcare have a valuable role, but may not, by themselves, yield full insight into the range of fallibilities in organizations. ‘Soft intelligence’ is usefully understood as the processes and behaviours associated with seeking and interpreting soft data—of the kind that evade easy capture, straightforward classification and simple quantification—to produce forms of knowledge that can provide the basis for intervention. With the aim of examining current and potential practice in relation to soft intelligence, we conducted and analysed 107 in-depth qualitative interviews with senior leaders, including managers and clinicians, involved in healthcare quality and safety in the English National Health Service. We found that participants were in little doubt about the value of softer forms of data, especially for their role in revealing troubling issues that might be obscured by conventional metrics. Their struggles lay in how to access softer data and turn them into a useful form of knowing. Some of the dominant approaches they used risked replicating the limitations of hard, quantitative data. They relied on processes of aggregation and triangulation that prioritised reliability, or on instrumental use of soft data to animate the metrics. The unpredictable, untameable, spontaneous quality of soft data could be lost in efforts to systematize their collection and interpretation to render them more tractable. A more challenging but potentially rewarding approach involved processes and behaviours aimed at disrupting taken-for-granted assumptions about quality, safety, and organizational performance. This approach, which explicitly values the seeking out and the hearing of multiple voices, is consistent with conceptual frameworks of organizational sensemaking and dialogical understandings of knowledge. Using soft intelligence this way can be challenging and discomfiting, but may offer a critical defence

Leveraging multi-channel x-ray detector technology to improve quality metrics for industrial and security applications

NASA Astrophysics Data System (ADS)

Jimenez, Edward S.; Thompson, Kyle R.; Stohn, Adriana; Goodner, Ryan N.

2017-09-01

Sandia National Laboratories has recently developed the capability to acquire multi-channel radio- graphs for multiple research and development applications in industry and security. This capability allows for the acquisition of x-ray radiographs or sinogram data to be acquired at up to 300 keV with up to 128 channels per pixel. This work will investigate whether multiple quality metrics for computed tomography can actually benefit from binned projection data compared to traditionally acquired grayscale sinogram data. Features and metrics to be evaluated include the ability to dis- tinguish between two different materials with similar absorption properties, artifact reduction, and signal-to-noise for both raw data and reconstructed volumetric data. The impact of this technology to non-destructive evaluation, national security, and industry is wide-ranging and has to potential to improve upon many inspection methods such as dual-energy methods, material identification, object segmentation, and computer vision on radiographs.

Methods of Measurement the Quality Metrics in a Printing System

NASA Astrophysics Data System (ADS)

Varepo, L. G.; Brazhnikov, A. Yu; Nagornova, I. V.; Novoselskaya, O. A.

2018-04-01

One of the main criteria for choosing ink as a component of printing system is scumming ability of the ink. The realization of algorithm for estimating the quality metrics in a printing system is shown. The histograms of ink rate of various printing systems are presented. A quantitative estimation of stability of offset inks emulsifiability is given.

Model-Based Referenceless Quality Metric of 3D Synthesized Images Using Local Image Description.

PubMed

Gu, Ke; Jakhetiya, Vinit; Qiao, Jun-Fei; Li, Xiaoli; Lin, Weisi; Thalmann, Daniel

2017-07-28

New challenges have been brought out along with the emerging of 3D-related technologies such as virtual reality (VR), augmented reality (AR), and mixed reality (MR). Free viewpoint video (FVV), due to its applications in remote surveillance, remote education, etc, based on the flexible selection of direction and viewpoint, has been perceived as the development direction of next-generation video technologies and has drawn a wide range of researchers' attention. Since FVV images are synthesized via a depth image-based rendering (DIBR) procedure in the "blind" environment (without reference images), a reliable real-time blind quality evaluation and monitoring system is urgently required. But existing assessment metrics do not render human judgments faithfully mainly because geometric distortions are generated by DIBR. To this end, this paper proposes a novel referenceless quality metric of DIBR-synthesized images using the autoregression (AR)-based local image description. It was found that, after the AR prediction, the reconstructed error between a DIBR-synthesized image and its AR-predicted image can accurately capture the geometry distortion. The visual saliency is then leveraged to modify the proposed blind quality metric to a sizable margin. Experiments validate the superiority of our no-reference quality method as compared with prevailing full-, reduced- and no-reference models.

Hospital readiness for health information exchange: development of metrics associated with successful collaboration for quality improvement

PubMed Central

Korst, Lisa M.; Aydin, Carolyn E.; Signer, Jordana M. K.; Fink, Arlene

2011-01-01

Objective The development of readiness metrics for organizational participation in health information exchange is critical for monitoring progress toward, and achievement of, successful inter-organizational collaboration. In preparation for the development of a tool to measure readiness for data-sharing, we tested whether organizational capacities known to be related to readiness were associated with successful participation in an American data-sharing collaborative for quality improvement. Design Cross-sectional design, using an on-line survey of hospitals in a large, mature data-sharing collaborative organized for benchmarking and improvement in nursing care quality. Measurements Factor analysis was used to identify salient constructs, and identified factors were analyzed with respect to “successful” participation. “Success” was defined as the incorporation of comparative performance data into the hospital dashboard. Results The most important factor in predicting success included survey items measuring the strength of organizational leadership in fostering a culture of quality improvement (QI Leadership): 1) presence of a supportive hospital executive; 2) the extent to which a hospital values data; 3) the presence of leaders’ vision for how the collaborative advances the hospital’s strategic goals; 4) hospital use of the collaborative data to track quality outcomes; and 5) staff recognition of a strong mandate for collaborative participation (α = 0.84, correlation with Success 0.68 [P < 0.0001]). Conclusion The data emphasize the importance of hospital QI Leadership in collaboratives that aim to share data for QI or safety purposes. Such metrics should prove useful in the planning and development of this complex form of inter-organizational collaboration. PMID:21330191

SU-E-I-71: Quality Assessment of Surrogate Metrics in Multi-Atlas-Based Image Segmentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, T; Ruan, D

Purpose: With the ever-growing data of heterogeneous quality, relevance assessment of atlases becomes increasingly critical for multi-atlas-based image segmentation. However, there is no universally recognized best relevance metric and even a standard to compare amongst candidates remains elusive. This study, for the first time, designs a quantification to assess relevance metrics’ quality, based on a novel perspective of the metric as surrogate for inferring the inaccessible oracle geometric agreement. Methods: We first develop an inference model to relate surrogate metrics in image space to the underlying oracle relevance metric in segmentation label space, with a monotonically non-decreasing function subject tomore » random perturbations. Subsequently, we investigate model parameters to reveal key contributing factors to surrogates’ ability in prognosticating the oracle relevance value, for the specific task of atlas selection. Finally, we design an effective contract-to-noise ratio (eCNR) to quantify surrogates’ quality based on insights from these analyses and empirical observations. Results: The inference model was specialized to a linear function with normally distributed perturbations, with surrogate metric exemplified by several widely-used image similarity metrics, i.e., MSD/NCC/(N)MI. Surrogates’ behaviors in selecting the most relevant atlases were assessed under varying eCNR, showing that surrogates with high eCNR dominated those with low eCNR in retaining the most relevant atlases. In an end-to-end validation, NCC/(N)MI with eCNR of 0.12 compared to MSD with eCNR of 0.10 resulted in statistically better segmentation with mean DSC of about 0.85 and the first and third quartiles of (0.83, 0.89), compared to MSD with mean DSC of 0.84 and the first and third quartiles of (0.81, 0.89). Conclusion: The designed eCNR is capable of characterizing surrogate metrics’ quality in prognosticating the oracle relevance value. It has been demonstrated to

Effect of quality metric monitoring and colonoscopy performance.

PubMed

Razzak, Anthony; Smith, Dineen; Zahid, Maliha; Papachristou, Georgios; Khalid, Asif

2016-10-01

Background and aims: Adenoma detection rate (ADR) and cecal withdrawal time (CWT) have been identified as measures of colonoscopy quality. This study evaluates the impact of monitoring these measures on provider performance. Methods: Six blinded gastroenterologists practicing at a Veterans Affairs Medical Center were prospectively monitored over 9 months. Data for screening, adenoma surveillance, and fecal occult blood test positive (FOBT +) indicated colonoscopies were obtained, including exam preparation quality, cecal intubation rate, CWT, ADR, adenomas per colonoscopy (APC), and adverse events. Metrics were continuously monitored after a period of informed CWT monitoring and informed CWT + ADR monitoring. The primary outcome was impact on ADR and APC. Results: A total of 1671 colonoscopies were performed during the study period with 540 before informed monitoring, 528 during informed CWT monitoring, and 603 during informed CWT + ADR monitoring. No statistically significant impact on ADR was noted across each study phase. Multivariate regression revealed a trend towards fewer adenomas removed during the CWT monitoring phase (OR = 0.79; 95 %CI 0.62 - 1.02, P  = 0.065) and a trend towards more adenomas removed during the CWT + ADR monitoring phase when compared to baseline (OR = 1.26; 95 %CI 0.99 - 1.61, P  = 0.062). Indication for examination and provider were significant predictors for higher APC. Provider-specific data demonstrated a direct relationship between high ADR performers and increased CWT. Conclusions: Monitoring quality metrics did not significantly alter colonoscopy performance across a small heterogeneous group of providers. Non-significant trends towards higher APC were noted with CWT + ADR monitoring. Providers with a longer CWT had a higher ADR. Further studies are needed to determine the impact of monitoring on colonoscopy performance.

Macroinvertebrate and diatom metrics as indicators of water-quality conditions in connected depression wetlands in the Mississippi Alluvial Plain

USGS Publications Warehouse

Justus, Billy; Burge, David; Cobb, Jennifer; Marsico, Travis; Bouldin, Jennifer

2016-01-01

Methods for assessing wetland conditions must be established so wetlands can be monitored and ecological services can be protected. We evaluated biological indices compiled from macroinvertebrate and diatom metrics developed primarily for streams to assess their ability to indicate water quality in connected depression wetlands. We collected water-quality and biological samples at 24 connected depressions dominated by water tupelo (Nyssa aquatica) or bald cypress (Taxodium distichum) (water depths = 0.5–1.0 m). Water quality of the least-disturbed connected depressions was characteristic of swamps in the southeastern USA, which tend to have low specific conductance, nutrient concentrations, and pH. We compared 162 macroinvertebrate metrics and 123 diatom metrics with a water-quality disturbance gradient. For most metrics, we evaluated richness, % richness, abundance, and % relative abundance values. Three of the 4 macroinvertebrate metrics that were most beneficial for identifying disturbance in connected depressions decreased along the disturbance gradient even though they normally increase relative to stream disturbance. The negative relationship to disturbance of some taxa (e.g., dipterans, mollusks, and crustaceans) that are considered tolerant in streams suggests that the tolerance scale for some macroinvertebrates can differ markedly between streams and wetlands. Three of the 4 metrics chosen for the diatom index reflected published tolerances or fit the usual perception of metric response to disturbance. Both biological indices may be useful in connected depressions elsewhere in the Mississippi Alluvial Plain Ecoregion and could have application in other wetland types. Given the paradoxical relationship of some macroinvertebrate metrics to dissolved O2 (DO), we suggest that the diatom metrics may be easier to interpret and defend for wetlands with low DO concentrations in least-disturbed conditions.

Stochastic HKMDHE: A multi-objective contrast enhancement algorithm

NASA Astrophysics Data System (ADS)

Pratiher, Sawon; Mukhopadhyay, Sabyasachi; Maity, Srideep; Pradhan, Asima; Ghosh, Nirmalya; Panigrahi, Prasanta K.

2018-02-01

This contribution proposes a novel extension of the existing `Hyper Kurtosis based Modified Duo-Histogram Equalization' (HKMDHE) algorithm, for multi-objective contrast enhancement of biomedical images. A novel modified objective function has been formulated by joint optimization of the individual histogram equalization objectives. The optimal adequacy of the proposed methodology with respect to image quality metrics such as brightness preserving abilities, peak signal-to-noise ratio (PSNR), Structural Similarity Index (SSIM) and universal image quality metric has been experimentally validated. The performance analysis of the proposed Stochastic HKMDHE with existing histogram equalization methodologies like Global Histogram Equalization (GHE) and Contrast Limited Adaptive Histogram Equalization (CLAHE) has been given for comparative evaluation.

Testing, Requirements, and Metrics

NASA Technical Reports Server (NTRS)

Rosenberg, Linda; Hyatt, Larry; Hammer, Theodore F.; Huffman, Lenore; Wilson, William

1998-01-01

The criticality of correct, complete, testable requirements is a fundamental tenet of software engineering. Also critical is complete requirements based testing of the final product. Modern tools for managing requirements allow new metrics to be used in support of both of these critical processes. Using these tools, potential problems with the quality of the requirements and the test plan can be identified early in the life cycle. Some of these quality factors include: ambiguous or incomplete requirements, poorly designed requirements databases, excessive or insufficient test cases, and incomplete linkage of tests to requirements. This paper discusses how metrics can be used to evaluate the quality of the requirements and test to avoid problems later. Requirements management and requirements based testing have always been critical in the implementation of high quality software systems. Recently, automated tools have become available to support requirements management. At NASA's Goddard Space Flight Center (GSFC), automated requirements management tools are being used on several large projects. The use of these tools opens the door to innovative uses of metrics in characterizing test plan quality and assessing overall testing risks. In support of these projects, the Software Assurance Technology Center (SATC) is working to develop and apply a metrics program that utilizes the information now available through the application of requirements management tools. Metrics based on this information provides real-time insight into the testing of requirements and these metrics assist the Project Quality Office in its testing oversight role. This paper discusses three facets of the SATC's efforts to evaluate the quality of the requirements and test plan early in the life cycle, thus preventing costly errors and time delays later.

qcML: An Exchange Format for Quality Control Metrics from Mass Spectrometry Experiments*

PubMed Central

Walzer, Mathias; Pernas, Lucia Espona; Nasso, Sara; Bittremieux, Wout; Nahnsen, Sven; Kelchtermans, Pieter; Pichler, Peter; van den Toorn, Henk W. P.; Staes, An; Vandenbussche, Jonathan; Mazanek, Michael; Taus, Thomas; Scheltema, Richard A.; Kelstrup, Christian D.; Gatto, Laurent; van Breukelen, Bas; Aiche, Stephan; Valkenborg, Dirk; Laukens, Kris; Lilley, Kathryn S.; Olsen, Jesper V.; Heck, Albert J. R.; Mechtler, Karl; Aebersold, Ruedi; Gevaert, Kris; Vizcaíno, Juan Antonio; Hermjakob, Henning; Kohlbacher, Oliver; Martens, Lennart

2014-01-01

Quality control is increasingly recognized as a crucial aspect of mass spectrometry based proteomics. Several recent papers discuss relevant parameters for quality control and present applications to extract these from the instrumental raw data. What has been missing, however, is a standard data exchange format for reporting these performance metrics. We therefore developed the qcML format, an XML-based standard that follows the design principles of the related mzML, mzIdentML, mzQuantML, and TraML standards from the HUPO-PSI (Proteomics Standards Initiative). In addition to the XML format, we also provide tools for the calculation of a wide range of quality metrics as well as a database format and interconversion tools, so that existing LIMS systems can easily add relational storage of the quality control data to their existing schema. We here describe the qcML specification, along with possible use cases and an illustrative example of the subsequent analysis possibilities. All information about qcML is available at http://code.google.com/p/qcml. PMID:24760958

qcML: an exchange format for quality control metrics from mass spectrometry experiments.

PubMed

Walzer, Mathias; Pernas, Lucia Espona; Nasso, Sara; Bittremieux, Wout; Nahnsen, Sven; Kelchtermans, Pieter; Pichler, Peter; van den Toorn, Henk W P; Staes, An; Vandenbussche, Jonathan; Mazanek, Michael; Taus, Thomas; Scheltema, Richard A; Kelstrup, Christian D; Gatto, Laurent; van Breukelen, Bas; Aiche, Stephan; Valkenborg, Dirk; Laukens, Kris; Lilley, Kathryn S; Olsen, Jesper V; Heck, Albert J R; Mechtler, Karl; Aebersold, Ruedi; Gevaert, Kris; Vizcaíno, Juan Antonio; Hermjakob, Henning; Kohlbacher, Oliver; Martens, Lennart

2014-08-01

Quality control is increasingly recognized as a crucial aspect of mass spectrometry based proteomics. Several recent papers discuss relevant parameters for quality control and present applications to extract these from the instrumental raw data. What has been missing, however, is a standard data exchange format for reporting these performance metrics. We therefore developed the qcML format, an XML-based standard that follows the design principles of the related mzML, mzIdentML, mzQuantML, and TraML standards from the HUPO-PSI (Proteomics Standards Initiative). In addition to the XML format, we also provide tools for the calculation of a wide range of quality metrics as well as a database format and interconversion tools, so that existing LIMS systems can easily add relational storage of the quality control data to their existing schema. We here describe the qcML specification, along with possible use cases and an illustrative example of the subsequent analysis possibilities. All information about qcML is available at http://code.google.com/p/qcml. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Evaluation techniques and metrics for assessment of pan+MSI fusion (pansharpening)

NASA Astrophysics Data System (ADS)

Mercovich, Ryan A.

2015-05-01

Fusion of broadband panchromatic data with narrow band multispectral data - pansharpening - is a common and often studied problem in remote sensing. Many methods exist to produce data fusion results with the best possible spatial and spectral characteristics, and a number have been commercially implemented. This study examines the output products of 4 commercial implementations with regard to their relative strengths and weaknesses for a set of defined image characteristics and analyst use-cases. Image characteristics used are spatial detail, spatial quality, spectral integrity, and composite color quality (hue and saturation), and analyst use-cases included a variety of object detection and identification tasks. The imagery comes courtesy of the RIT SHARE 2012 collect. Two approaches are used to evaluate the pansharpening methods, analyst evaluation or qualitative measure and image quality metrics or quantitative measures. Visual analyst evaluation results are compared with metric results to determine which metrics best measure the defined image characteristics and product use-cases and to support future rigorous characterization the metrics' correlation with the analyst results. Because pansharpening represents a trade between adding spatial information from the panchromatic image, and retaining spectral information from the MSI channels, the metrics examined are grouped into spatial improvement metrics and spectral preservation metrics. A single metric to quantify the quality of a pansharpening method would necessarily be a combination of weighted spatial and spectral metrics based on the importance of various spatial and spectral characteristics for the primary task of interest. Appropriate metrics and weights for such a combined metric are proposed here, based on the conducted analyst evaluation. Additionally, during this work, a metric was developed specifically focused on assessment of spatial structure improvement relative to a reference image and

The importance of metrics for evaluating scientific performance

NASA Astrophysics Data System (ADS)

Miyakawa, Tsuyoshi

Evaluation of scientific performance is a major factor that determines the behavior of both individual researchers and the academic institutes to which they belong. Because the number of researchers heavily outweighs the number of available research posts, and the competitive funding accounts for an ever-increasing proportion of research budget, some objective indicators of research performance have gained recognition for increasing transparency and openness. It is common practice to use metrics and indices to evaluate a researcher's performance or the quality of their grant applications. Such measures include the number of publications, the number of times these papers are cited and, more recently, the h-index, which measures the number of highly-cited papers the researcher has written. However, academic institutions and funding agencies in Japan have been rather slow to adopt such metrics. In this article, I will outline some of the currently available metrics, and discuss why we need to use such objective indicators of research performance more often in Japan. I will also discuss how to promote the use of metrics and what we should keep in mind when using them, as well as their potential impact on the research community in Japan.

A subjective study and an objective metric to quantify the granularity level of textures

NASA Astrophysics Data System (ADS)

Subedar, Mahesh M.; Karam, Lina J.

2015-03-01

Texture granularity is an important visual characteristic that is useful in a variety of applications, including analysis, recognition, and compression, to name a few. A texture granularity measure can be used to quantify the perceived level of texture granularity. The granularity level of the textures is influenced by the size of the texture primitives. A primitive is defined as the smallest recognizable repetitive object in the texture. If the texture has large primitives then the perceived granularity level tends to be lower as compared to a texture with smaller primitives. In this work we are presenting a texture granularity database referred as GranTEX which consists of 30 textures with varying levels of primitive sizes and granularity levels. The GranTEX database consists of both natural and man-made textures. A subjective study is conducted to measure the perceived granularity level of textures present in the GranTEX database. An objective metric that automatically measures the perceived granularity level of textures is also presented as part of this work. It is shown that the proposed granularity metric correlates well with the subjective granularity scores.

Non-accidental properties, metric invariance, and encoding by neurons in a model of ventral stream visual object recognition, VisNet.

PubMed

Rolls, Edmund T; Mills, W Patrick C

2018-05-01

When objects transform into different views, some properties are maintained, such as whether the edges are convex or concave, and these non-accidental properties are likely to be important in view-invariant object recognition. The metric properties, such as the degree of curvature, may change with different views, and are less likely to be useful in object recognition. It is shown that in a model of invariant visual object recognition in the ventral visual stream, VisNet, non-accidental properties are encoded much more than metric properties by neurons. Moreover, it is shown how with the temporal trace rule training in VisNet, non-accidental properties of objects become encoded by neurons, and how metric properties are treated invariantly. We also show how VisNet can generalize between different objects if they have the same non-accidental property, because the metric properties are likely to overlap. VisNet is a 4-layer unsupervised model of visual object recognition trained by competitive learning that utilizes a temporal trace learning rule to implement the learning of invariance using views that occur close together in time. A second crucial property of this model of object recognition is, when neurons in the level corresponding to the inferior temporal visual cortex respond selectively to objects, whether neurons in the intermediate layers can respond to combinations of features that may be parts of two or more objects. In an investigation using the four sides of a square presented in every possible combination, it was shown that even though different layer 4 neurons are tuned to encode each feature or feature combination orthogonally, neurons in the intermediate layers can respond to features or feature combinations present is several objects. This property is an important part of the way in which high capacity can be achieved in the four-layer ventral visual cortical pathway. These findings concerning non-accidental properties and the use of neurons in

Natural Language Processing As an Alternative to Manual Reporting of Colonoscopy Quality Metrics

PubMed Central

RAJU, GOTTUMUKKALA S.; LUM, PHILLIP J.; SLACK, REBECCA; THIRUMURTHI, SELVI; LYNCH, PATRICK M.; MILLER, ETHAN; WESTON, BRIAN R.; DAVILA, MARTA L.; BHUTANI, MANOOP S.; SHAFI, MEHNAZ A.; BRESALIER, ROBERT S.; DEKOVICH, ALEXANDER A.; LEE, JEFFREY H.; GUHA, SUSHOVAN; PANDE, MALA; BLECHACZ, BORIS; RASHID, ASIF; ROUTBORT, MARK; SHUTTLESWORTH, GLADIS; MISHRA, LOPA; STROEHLEIN, JOHN R.; ROSS, WILLIAM A.

2015-01-01

BACKGROUND & AIMS The adenoma detection rate (ADR) is a quality metric tied to interval colon cancer occurrence. However, manual extraction of data to calculate and track the ADR in clinical practice is labor-intensive. To overcome this difficulty, we developed a natural language processing (NLP) method to identify patients, who underwent their first screening colonoscopy, identify adenomas and sessile serrated adenomas (SSA). We compared the NLP generated results with that of manual data extraction to test the accuracy of NLP, and report on colonoscopy quality metrics using NLP. METHODS Identification of screening colonoscopies using NLP was compared with that using the manual method for 12,748 patients who underwent colonoscopies from July 2010 to February 2013. Also, identification of adenomas and SSAs using NLP was compared with that using the manual method with 2259 matched patient records. Colonoscopy ADRs using these methods were generated for each physician. RESULTS NLP correctly identified 91.3% of the screening examinations, whereas the manual method identified 87.8% of them. Both the manual method and NLP correctly identified examinations of patients with adenomas and SSAs in the matched records almost perfectly. Both NLP and manual method produce comparable values for ADR for each endoscopist as well as the group as a whole. CONCLUSIONS NLP can correctly identify screening colonoscopies, accurately identify adenomas and SSAs in a pathology database, and provide real-time quality metrics for colonoscopy. PMID:25910665

Impact of artifact removal on ChIP quality metrics in ChIP-seq and ChIP-exo data

PubMed Central

Carroll, Thomas S.; Liang, Ziwei; Salama, Rafik; Stark, Rory; de Santiago, Ines

2014-01-01

With the advent of ChIP-seq multiplexing technologies and the subsequent increase in ChIP-seq throughput, the development of working standards for the quality assessment of ChIP-seq studies has received significant attention. The ENCODE consortium's large scale analysis of transcription factor binding and epigenetic marks as well as concordant work on ChIP-seq by other laboratories has established a new generation of ChIP-seq quality control measures. The use of these metrics alongside common processing steps has however not been evaluated. In this study, we investigate the effects of blacklisting and removal of duplicated reads on established metrics of ChIP-seq quality and show that the interpretation of these metrics is highly dependent on the ChIP-seq preprocessing steps applied. Further to this we perform the first investigation of the use of these metrics for ChIP-exo data and make recommendations for the adaptation of the NSC statistic to allow for the assessment of ChIP-exo efficiency. PMID:24782889

MO-A-16A-01: QA Procedures and Metrics: In Search of QA Usability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sathiaseelan, V; Thomadsen, B

Radiation therapy has undergone considerable changes in the past two decades with a surge of new technology and treatment delivery methods. The complexity of radiation therapy treatments has increased and there has been increased awareness and publicity about the associated risks. In response, there has been proliferation of guidelines for medical physicists to adopt to ensure that treatments are delivered safely. Task Group recommendations are copious, and clinical physicists' hours are longer, stretched to various degrees between site planning and management, IT support, physics QA, and treatment planning responsibilities.Radiation oncology has many quality control practices in place to ensure themore » delivery of high-quality, safe treatments. Incident reporting systems have been developed to collect statistics about near miss events at many radiation oncology centers. However, tools are lacking to assess the impact of these various control measures. A recent effort to address this shortcoming is the work of Ford et al (2012) who recently published a methodology enumerating quality control quantification for measuring the effectiveness of safety barriers. Over 4000 near-miss incidents reported from 2 academic radiation oncology clinics were analyzed using quality control quantification, and a profile of the most effective quality control measures (metrics) was identified.There is a critical need to identify a QA metric to help the busy clinical physicists to focus their limited time and resources most effectively in order to minimize or eliminate errors in the radiation treatment delivery processes. In this symposium the usefulness of workflows and QA metrics to assure safe and high quality patient care will be explored.Two presentations will be given:Quality Metrics and Risk Management with High Risk Radiation Oncology ProceduresStrategies and metrics for quality management in the TG-100 Era Learning Objectives: Provide an overview and the need for QA

Large radius of curvature measurement based on the evaluation of interferogram-quality metric in non-null interferometry

NASA Astrophysics Data System (ADS)

Yang, Zhongming; Dou, Jiantai; Du, Jinyu; Gao, Zhishan

2018-03-01

Non-null interferometry could use to measure the radius of curvature (ROC), we have presented a virtual quadratic Newton rings phase-shifting moiré-fringes measurement method for large ROC measurement (Yang et al., 2016). In this paper, we propose a large ROC measurement method based on the evaluation of the interferogram-quality metric by the non-null interferometer. With the multi-configuration model of the non-null interferometric system in ZEMAX, the retrace errors and the phase introduced by the test surface are reconstructed. The interferogram-quality metric is obtained by the normalized phase-shifted testing Newton rings with the spherical surface model in the non-null interferometric system. The radius curvature of the test spherical surface can be obtained until the minimum of the interferogram-quality metric is found. Simulations and experimental results are verified the feasibility of our proposed method. For a spherical mirror with a ROC of 41,400 mm, the measurement accuracy is better than 0.13%.

Using animation quality metric to improve efficiency of global illumination computation for dynamic environments

NASA Astrophysics Data System (ADS)

Myszkowski, Karol; Tawara, Takehiro; Seidel, Hans-Peter

2002-06-01

In this paper, we consider applications of perception-based video quality metrics to improve the performance of global lighting computations for dynamic environments. For this purpose we extend the Visible Difference Predictor (VDP) developed by Daly to handle computer animations. We incorporate into the VDP the spatio-velocity CSF model developed by Kelly. The CSF model requires data on the velocity of moving patterns across the image plane. We use the 3D image warping technique to compensate for the camera motion, and we conservatively assume that the motion of animated objects (usually strong attractors of the visual attention) is fully compensated by the smooth pursuit eye motion. Our global illumination solution is based on stochastic photon tracing and takes advantage of temporal coherence of lighting distribution, by processing photons both in the spatial and temporal domains. The VDP is used to keep noise inherent in stochastic methods below the sensitivity level of the human observer. As a result a perceptually-consistent quality across all animation frames is obtained.

Application of Sigma Metrics Analysis for the Assessment and Modification of Quality Control Program in the Clinical Chemistry Laboratory of a Tertiary Care Hospital.

PubMed

Iqbal, Sahar; Mustansar, Tazeen

2017-03-01

Sigma is a metric that quantifies the performance of a process as a rate of Defects-Per-Million opportunities. In clinical laboratories, sigma metric analysis is used to assess the performance of laboratory process system. Sigma metric is also used as a quality management strategy for a laboratory process to improve the quality by addressing the errors after identification. The aim of this study is to evaluate the errors in quality control of analytical phase of laboratory system by sigma metric. For this purpose sigma metric analysis was done for analytes using the internal and external quality control as quality indicators. Results of sigma metric analysis were used to identify the gaps and need for modification in the strategy of laboratory quality control procedure. Sigma metric was calculated for quality control program of ten clinical chemistry analytes including glucose, chloride, cholesterol, triglyceride, HDL, albumin, direct bilirubin, total bilirubin, protein and creatinine, at two control levels. To calculate the sigma metric imprecision and bias was calculated with internal and external quality control data, respectively. The minimum acceptable performance was considered as 3 sigma. Westgard sigma rules were applied to customize the quality control procedure. Sigma level was found acceptable (≥3) for glucose (L2), cholesterol, triglyceride, HDL, direct bilirubin and creatinine at both levels of control. For rest of the analytes sigma metric was found <3. The lowest value for sigma was found for chloride (1.1) at L2. The highest value of sigma was found for creatinine (10.1) at L3. HDL was found with the highest sigma values at both control levels (8.8 and 8.0 at L2 and L3, respectively). We conclude that analytes with the sigma value <3 are required strict monitoring and modification in quality control procedure. In this study application of sigma rules provided us the practical solution for improved and focused design of QC procedure.

Parameter Search Algorithms for Microwave Radar-Based Breast Imaging: Focal Quality Metrics as Fitness Functions.

PubMed

O'Loughlin, Declan; Oliveira, Bárbara L; Elahi, Muhammad Adnan; Glavin, Martin; Jones, Edward; Popović, Milica; O'Halloran, Martin

2017-12-06

Inaccurate estimation of average dielectric properties can have a tangible impact on microwave radar-based breast images. Despite this, recent patient imaging studies have used a fixed estimate although this is known to vary from patient to patient. Parameter search algorithms are a promising technique for estimating the average dielectric properties from the reconstructed microwave images themselves without additional hardware. In this work, qualities of accurately reconstructed images are identified from point spread functions. As the qualities of accurately reconstructed microwave images are similar to the qualities of focused microscopic and photographic images, this work proposes the use of focal quality metrics for average dielectric property estimation. The robustness of the parameter search is evaluated using experimental dielectrically heterogeneous phantoms on the three-dimensional volumetric image. Based on a very broad initial estimate of the average dielectric properties, this paper shows how these metrics can be used as suitable fitness functions in parameter search algorithms to reconstruct clear and focused microwave radar images.

Recommendations for Mass Spectrometry Data Quality Metrics for Open Access Data (Corollary to the Amsterdam Principles)

PubMed Central

Kinsinger, Christopher R.; Apffel, James; Baker, Mark; Bian, Xiaopeng; Borchers, Christoph H.; Bradshaw, Ralph; Brusniak, Mi-Youn; Chan, Daniel W.; Deutsch, Eric W.; Domon, Bruno; Gorman, Jeff; Grimm, Rudolf; Hancock, William; Hermjakob, Henning; Horn, David; Hunter, Christie; Kolar, Patrik; Kraus, Hans-Joachim; Langen, Hanno; Linding, Rune; Moritz, Robert L.; Omenn, Gilbert S.; Orlando, Ron; Pandey, Akhilesh; Ping, Peipei; Rahbar, Amir; Rivers, Robert; Seymour, Sean L.; Simpson, Richard J.; Slotta, Douglas; Smith, Richard D.; Stein, Stephen E.; Tabb, David L.; Tagle, Danilo; Yates, John R.; Rodriguez, Henry

2011-01-01

Policies supporting the rapid and open sharing of proteomic data are being implemented by the leading journals in the field. The proteomics community is taking steps to ensure that data are made publicly accessible and are of high quality, a challenging task that requires the development and deployment of methods for measuring and documenting data quality metrics. On September 18, 2010, the U.S. National Cancer Institute (NCI) convened the “International Workshop on Proteomic Data Quality Metrics” in Sydney, Australia, to identify and address issues facing the development and use of such methods for open access proteomics data. The stakeholders at the workshop enumerated the key principles underlying a framework for data quality assessment in mass spectrometry data that will meet the needs of the research community, journals, funding agencies, and data repositories. Attendees discussed and agreed up on two primary needs for the wide use of quality metrics: (1) an evolving list of comprehensive quality metrics and (2) standards accompanied by software analytics. Attendees stressed the importance of increased education and training programs to promote reliable protocols in proteomics. This workshop report explores the historic precedents, key discussions, and necessary next steps to enhance the quality of open access data. By agreement, this article is published simultaneously in the Journal of Proteome Research, Molecular and Cellular Proteomics, Proteomics, and Proteomics Clinical Applications as a public service to the research community. The peer review process was a coordinated effort conducted by a panel of referees selected by the journals. PMID:22053864

Recommendations for Mass Spectrometry Data Quality Metrics for Open Access Data (Corollary to the Amsterdam Principles)*

PubMed Central

Kinsinger, Christopher R.; Apffel, James; Baker, Mark; Bian, Xiaopeng; Borchers, Christoph H.; Bradshaw, Ralph; Brusniak, Mi-Youn; Chan, Daniel W.; Deutsch, Eric W.; Domon, Bruno; Gorman, Jeff; Grimm, Rudolf; Hancock, William; Hermjakob, Henning; Horn, David; Hunter, Christie; Kolar, Patrik; Kraus, Hans-Joachim; Langen, Hanno; Linding, Rune; Moritz, Robert L.; Omenn, Gilbert S.; Orlando, Ron; Pandey, Akhilesh; Ping, Peipei; Rahbar, Amir; Rivers, Robert; Seymour, Sean L.; Simpson, Richard J.; Slotta, Douglas; Smith, Richard D.; Stein, Stephen E.; Tabb, David L.; Tagle, Danilo; Yates, John R.; Rodriguez, Henry

2011-01-01

Policies supporting the rapid and open sharing of proteomic data are being implemented by the leading journals in the field. The proteomics community is taking steps to ensure that data are made publicly accessible and are of high quality, a challenging task that requires the development and deployment of methods for measuring and documenting data quality metrics. On September 18, 2010, the United States National Cancer Institute convened the “International Workshop on Proteomic Data Quality Metrics” in Sydney, Australia, to identify and address issues facing the development and use of such methods for open access proteomics data. The stakeholders at the workshop enumerated the key principles underlying a framework for data quality assessment in mass spectrometry data that will meet the needs of the research community, journals, funding agencies, and data repositories. Attendees discussed and agreed up on two primary needs for the wide use of quality metrics: 1) an evolving list of comprehensive quality metrics and 2) standards accompanied by software analytics. Attendees stressed the importance of increased education and training programs to promote reliable protocols in proteomics. This workshop report explores the historic precedents, key discussions, and necessary next steps to enhance the quality of open access data. By agreement, this article is published simultaneously in the Journal of Proteome Research, Molecular and Cellular Proteomics, Proteomics, and Proteomics Clinical Applications as a public service to the research community. The peer review process was a coordinated effort conducted by a panel of referees selected by the journals. PMID:22052993

Viewpoint matters: objective performance metrics for surgeon endoscope control during robot-assisted surgery.

PubMed

Jarc, Anthony M; Curet, Myriam J

2017-03-01

Effective visualization of the operative field is vital to surgical safety and education. However, additional metrics for visualization are needed to complement other common measures of surgeon proficiency, such as time or errors. Unlike other surgical modalities, robot-assisted minimally invasive surgery (RAMIS) enables data-driven feedback to trainees through measurement of camera adjustments. The purpose of this study was to validate and quantify the importance of novel camera metrics during RAMIS. New (n = 18), intermediate (n = 8), and experienced (n = 13) surgeons completed 25 virtual reality simulation exercises on the da Vinci Surgical System. Three camera metrics were computed for all exercises and compared to conventional efficiency measures. Both camera metrics and efficiency metrics showed construct validity (p < 0.05) across most exercises (camera movement frequency 23/25, camera movement duration 22/25, camera movement interval 19/25, overall score 24/25, completion time 25/25). Camera metrics differentiated new and experienced surgeons across all tasks as well as efficiency metrics. Finally, camera metrics significantly (p < 0.05) correlated with completion time (camera movement frequency 21/25, camera movement duration 21/25, camera movement interval 20/25) and overall score (camera movement frequency 20/25, camera movement duration 19/25, camera movement interval 20/25) for most exercises. We demonstrate construct validity of novel camera metrics and correlation between camera metrics and efficiency metrics across many simulation exercises. We believe camera metrics could be used to improve RAMIS proficiency-based curricula.

Toward determining melt pool quality metrics via coaxial monitoring in laser powder bed fusion.

PubMed

Fisher, Brian A; Lane, Brandon; Yeung, Ho; Beuth, Jack

2018-01-01

The current industry trend in metal additive manufacturing is towards greater real time process monitoring capabilities during builds to ensure high quality parts. While the hardware implementations that allow for real time monitoring of the melt pool have advanced significantly, the knowledge required to correlate the generated data to useful metrics of interest are still lacking. This research presents promising results that aim to bridge this knowledge gap by determining a novel means to correlate easily obtainable sensor data (thermal emission) to key melt pool size metrics (e.g., melt pool cross sectional area).

Improvement of impact noise in a passenger car utilizing sound metric based on wavelet transform

NASA Astrophysics Data System (ADS)

Lee, Sang-Kwon; Kim, Ho-Wuk; Na, Eun-Woo

2010-08-01

A new sound metric for impact sound is developed based on the continuous wavelet transform (CWT), a useful tool for the analysis of non-stationary signals such as impact noise. Together with new metric, two other conventional sound metrics related to sound modulation and fluctuation are also considered. In all, three sound metrics are employed to develop impact sound quality indexes for several specific impact courses on the road. Impact sounds are evaluated subjectively by 25 jurors. The indexes are verified by comparing the correlation between the index output and results of a subjective evaluation based on a jury test. These indexes are successfully applied to an objective evaluation for improvement of the impact sound quality for cases where some parts of the suspension system of the test car are modified.

Evaluation of the performance of a micromethod for measuring urinary iodine by using six sigma quality metrics.

PubMed

Hussain, Husniza; Khalid, Norhayati Mustafa; Selamat, Rusidah; Wan Nazaimoon, Wan Mohamud

2013-09-01

The urinary iodine micromethod (UIMM) is a modification of the conventional method and its performance needs evaluation. UIMM performance was evaluated using the method validation and 2008 Iodine Deficiency Disorders survey data obtained from four urinary iodine (UI) laboratories. Method acceptability tests and Sigma quality metrics were determined using total allowable errors (TEas) set by two external quality assurance (EQA) providers. UIMM obeyed various method acceptability test criteria with some discrepancies at low concentrations. Method validation data calculated against the UI Quality Program (TUIQP) TEas showed that the Sigma metrics were at 2.75, 1.80, and 3.80 for 51±15.50 µg/L, 108±32.40 µg/L, and 149±38.60 µg/L UI, respectively. External quality control (EQC) data showed that the performance of the laboratories was within Sigma metrics of 0.85-1.12, 1.57-4.36, and 1.46-4.98 at 46.91±7.05 µg/L, 135.14±13.53 µg/L, and 238.58±17.90 µg/L, respectively. No laboratory showed a calculated total error (TEcalc)Quality of UI Procedures (EQUIP) TEas, the performance of all laboratories was≤2.49 Sigma metrics at all concentrations. Only one laboratory had TEcalc

Correlating objective and subjective evaluation of texture appearance with applications to camera phone imaging

NASA Astrophysics Data System (ADS)

Phillips, Jonathan B.; Coppola, Stephen M.; Jin, Elaine W.; Chen, Ying; Clark, James H.; Mauer, Timothy A.

2009-01-01

Texture appearance is an important component of photographic image quality as well as object recognition. Noise cleaning algorithms are used to decrease sensor noise of digital images, but can hinder texture elements in the process. The Camera Phone Image Quality (CPIQ) initiative of the International Imaging Industry Association (I3A) is developing metrics to quantify texture appearance. Objective and subjective experimental results of the texture metric development are presented in this paper. Eight levels of noise cleaning were applied to ten photographic scenes that included texture elements such as faces, landscapes, architecture, and foliage. Four companies (Aptina Imaging, LLC, Hewlett-Packard, Eastman Kodak Company, and Vista Point Technologies) have performed psychophysical evaluations of overall image quality using one of two methods of evaluation. Both methods presented paired comparisons of images on thin film transistor liquid crystal displays (TFT-LCD), but the display pixel pitch and viewing distance differed. CPIQ has also been developing objective texture metrics and targets that were used to analyze the same eight levels of noise cleaning. The correlation of the subjective and objective test results indicates that texture perception can be modeled with an objective metric. The two methods of psychophysical evaluation exhibited high correlation despite the differences in methodology.

Metric invariance in object recognition: a review and further evidence.

PubMed

Cooper, E E; Biederman, I; Hummel, J E

1992-06-01

Phenomenologically, human shape recognition appears to be invariant with changes of orientation in depth (up to parts occlusion), position in the visual field, and size. Recent versions of template theories (e.g., Ullman, 1989; Lowe, 1987) assume that these invariances are achieved through the application of transformations such as rotation, translation, and scaling of the image so that it can be matched metrically to a stored template. Presumably, such transformations would require time for their execution. We describe recent priming experiments in which the effects of a prior brief presentation of an image on its subsequent recognition are assessed. The results of these experiments indicate that the invariance is complete: The magnitude of visual priming (as distinct from name or basic level concept priming) is not affected by a change in position, size, orientation in depth, or the particular lines and vertices present in the image, as long as representations of the same components can be activated. An implemented seven layer neural network model (Hummel & Biederman, 1992) that captures these fundamental properties of human object recognition is described. Given a line drawing of an object, the model activates a viewpoint-invariant structural description of the object, specifying its parts and their interrelations. Visual priming is interpreted as a change in the connection weights for the activation of: a) cells, termed geon feature assemblies (GFAs), that conjoin the output of units that represent invariant, independent properties of a single geon and its relations (such as its type, aspect ratio, relations to other geons), or b) a change in the connection weights by which several GFAs activate a cell representing an object.

Applying Sigma Metrics to Reduce Outliers.

PubMed

Litten, Joseph

2017-03-01

Sigma metrics can be used to predict assay quality, allowing easy comparison of instrument quality and predicting which tests will require minimal quality control (QC) rules to monitor the performance of the method. A Six Sigma QC program can result in fewer controls and fewer QC failures for methods with a sigma metric of 5 or better. The higher the number of methods with a sigma metric of 5 or better, the lower the costs for reagents, supplies, and control material required to monitor the performance of the methods. Copyright © 2016 Elsevier Inc. All rights reserved.

JPEG2000 still image coding quality.

PubMed

Chen, Tzong-Jer; Lin, Sheng-Chieh; Lin, You-Chen; Cheng, Ren-Gui; Lin, Li-Hui; Wu, Wei

2013-10-01

This work demonstrates the image qualities between two popular JPEG2000 programs. Two medical image compression algorithms are both coded using JPEG2000, but they are different regarding the interface, convenience, speed of computation, and their characteristic options influenced by the encoder, quantization, tiling, etc. The differences in image quality and compression ratio are also affected by the modality and compression algorithm implementation. Do they provide the same quality? The qualities of compressed medical images from two image compression programs named Apollo and JJ2000 were evaluated extensively using objective metrics. These algorithms were applied to three medical image modalities at various compression ratios ranging from 10:1 to 100:1. Following that, the quality of the reconstructed images was evaluated using five objective metrics. The Spearman rank correlation coefficients were measured under every metric in the two programs. We found that JJ2000 and Apollo exhibited indistinguishable image quality for all images evaluated using the above five metrics (r > 0.98, p < 0.001). It can be concluded that the image quality of the JJ2000 and Apollo algorithms is statistically equivalent for medical image compression.

Evaluation of cassette-based digital radiography detectors using standardized image quality metrics: AAPM TG-150 Draft Image Detector Tests.

PubMed

Li, Guang; Greene, Travis C; Nishino, Thomas K; Willis, Charles E

2016-09-08

The purpose of this study was to evaluate several of the standardized image quality metrics proposed by the American Association of Physics in Medicine (AAPM) Task Group 150. The task group suggested region-of-interest (ROI)-based techniques to measure nonuniformity, minimum signal-to-noise ratio (SNR), number of anomalous pixels, and modulation transfer function (MTF). This study evaluated the effects of ROI size and layout on the image metrics by using four different ROI sets, assessed result uncertainty by repeating measurements, and compared results with two commercially available quality control tools, namely the Carestream DIRECTVIEW Total Quality Tool (TQT) and the GE Healthcare Quality Assurance Process (QAP). Seven Carestream DRX-1C (CsI) detectors on mobile DR systems and four GE FlashPad detectors in radiographic rooms were tested. Images were analyzed using MATLAB software that had been previously validated and reported. Our values for signal and SNR nonuniformity and MTF agree with values published by other investigators. Our results show that ROI size affects nonuniformity and minimum SNR measurements, but not detection of anomalous pixels. Exposure geometry affects all tested image metrics except for the MTF. TG-150 metrics in general agree with the TQT, but agree with the QAP only for local and global signal nonuniformity. The difference in SNR nonuniformity and MTF values between the TG-150 and QAP may be explained by differences in the calculation of noise and acquisition beam quality, respectively. TG-150's SNR nonuniformity metrics are also more sensitive to detector nonuniformity compared to the QAP. Our results suggest that fixed ROI size should be used for consistency because nonuniformity metrics depend on ROI size. Ideally, detector tests should be performed at the exact calibration position. If not feasible, a baseline should be established from the mean of several repeated measurements. Our study indicates that the TG-150 tests can be

Evaluation of cassette‐based digital radiography detectors using standardized image quality metrics: AAPM TG‐150 Draft Image Detector Tests

PubMed Central

Greene, Travis C.; Nishino, Thomas K.; Willis, Charles E.

2016-01-01

The purpose of this study was to evaluate several of the standardized image quality metrics proposed by the American Association of Physics in Medicine (AAPM) Task Group 150. The task group suggested region‐of‐interest (ROI)‐based techniques to measure nonuniformity, minimum signal‐to‐noise ratio (SNR), number of anomalous pixels, and modulation transfer function (MTF). This study evaluated the effects of ROI size and layout on the image metrics by using four different ROI sets, assessed result uncertainty by repeating measurements, and compared results with two commercially available quality control tools, namely the Carestream DIRECTVIEW Total Quality Tool (TQT) and the GE Healthcare Quality Assurance Process (QAP). Seven Carestream DRX‐1C (CsI) detectors on mobile DR systems and four GE FlashPad detectors in radiographic rooms were tested. Images were analyzed using MATLAB software that had been previously validated and reported. Our values for signal and SNR nonuniformity and MTF agree with values published by other investigators. Our results show that ROI size affects nonuniformity and minimum SNR measurements, but not detection of anomalous pixels. Exposure geometry affects all tested image metrics except for the MTF. TG‐150 metrics in general agree with the TQT, but agree with the QAP only for local and global signal nonuniformity. The difference in SNR nonuniformity and MTF values between the TG‐150 and QAP may be explained by differences in the calculation of noise and acquisition beam quality, respectively. TG‐150's SNR nonuniformity metrics are also more sensitive to detector nonuniformity compared to the QAP. Our results suggest that fixed ROI size should be used for consistency because nonuniformity metrics depend on ROI size. Ideally, detector tests should be performed at the exact calibration position. If not feasible, a baseline should be established from the mean of several repeated measurements. Our study indicates that the TG�

Quality metric for spherical panoramic video

NASA Astrophysics Data System (ADS)

Zakharchenko, Vladyslav; Choi, Kwang Pyo; Park, Jeong Hoon

2016-09-01

Virtual reality (VR)/ augmented reality (AR) applications allow users to view artificial content of a surrounding space simulating presence effect with a help of special applications or devices. Synthetic contents production is well known process form computer graphics domain and pipeline has been already fixed in the industry. However emerging multimedia formats for immersive entertainment applications such as free-viewpoint television (FTV) or spherical panoramic video require different approaches in content management and quality assessment. The international standardization on FTV has been promoted by MPEG. This paper is dedicated to discussion of immersive media distribution format and quality estimation process. Accuracy and reliability of the proposed objective quality estimation method had been verified with spherical panoramic images demonstrating good correlation results with subjective quality estimation held by a group of experts.

Establishing Quantitative Software Metrics in Department of the Navy Programs

DTIC Science & Technology

2016-04-01

13 Quality to Metrics Dependency Matrix...11 7. Quality characteristics to metrics dependecy matrix...In accomplishing this goal, a need exists for a formalized set of software quality metrics . This document establishes the validity of those necessary

Characterization of Pediatric In-Hospital Cardiopulmonary Resuscitation Quality Metrics Across an International Resuscitation Collaborative.

PubMed

Niles, Dana E; Duval-Arnould, Jordan; Skellett, Sophie; Knight, Lynda; Su, Felice; Raymond, Tia T; Sweberg, Todd; Sen, Anita I; Atkins, Dianne L; Friess, Stuart H; de Caen, Allan R; Kurosawa, Hiroshi; Sutton, Robert M; Wolfe, Heather; Berg, Robert A; Silver, Annemarie; Hunt, Elizabeth A; Nadkarni, Vinay M

2018-05-01

Pediatric in-hospital cardiac arrest cardiopulmonary resuscitation quality metrics have been reported in few children less than 8 years. Our objective was to characterize chest compression fraction, rate, depth, and compliance with 2015 American Heart Association guidelines across multiple pediatric hospitals. Retrospective observational study of data from a multicenter resuscitation quality collaborative from October 2015 to April 2017. Twelve pediatric hospitals across United States, Canada, and Europe. In-hospital cardiac arrest patients (age < 18 yr) with quantitative cardiopulmonary resuscitation data recordings. None. There were 112 events yielding 2,046 evaluable 60-second epochs of cardiopulmonary resuscitation (196,669 chest compression). Event cardiopulmonary resuscitation metric summaries (median [interquartile range]) by age: less than 1 year (38/112): chest compression fraction 0.88 (0.61-0.98), chest compression rate 119/min (110-129), and chest compression depth 2.3 cm (1.9-3.0 cm); for 1 to less than 8 years (42/112): chest compression fraction 0.94 (0.79-1.00), chest compression rate 117/min (110-124), and chest compression depth 3.8 cm (2.9-4.6 cm); for 8 to less than 18 years (32/112): chest compression fraction 0.94 (0.85-1.00), chest compression rate 117/min (110-123), chest compression depth 5.5 cm (4.0-6.5 cm). "Compliance" with guideline targets for 60-second chest compression "epochs" was predefined: chest compression fraction greater than 0.80, chest compression rate 100-120/min, and chest compression depth: greater than or equal to 3.4 cm in less than 1 year, greater than or equal to 4.4 cm in 1 to less than 8 years, and 4.5 to less than 6.6 cm in 8 to less than 18 years. Proportion of less than 1 year, 1 to less than 8 years, and 8 to less than 18 years events with greater than or equal to 60% of 60-second epochs meeting compliance (respectively): chest compression fraction was 53%, 81%, and 78%; chest compression rate

Using Qualitative and Quantitative Methods to Choose a Habitat Quality Metric for Air Pollution Policy Evaluation

PubMed Central

Ford, Adriana E. S.; Smart, Simon M.; Henrys, Peter A.; Ashmore, Mike R.

2016-01-01

Atmospheric nitrogen (N) deposition has had detrimental effects on species composition in a range of sensitive habitats, although N deposition can also increase agricultural productivity and carbon storage, and favours a few species considered of importance for conservation. Conservation targets are multiple, and increasingly incorporate services derived from nature as well as concepts of intrinsic value. Priorities vary. How then should changes in a set of species caused by drivers such as N deposition be assessed? We used a novel combination of qualitative semi-structured interviews and quantitative ranking to elucidate the views of conservation professionals specialising in grasslands, heathlands and mires. Although conservation management goals are varied, terrestrial habitat quality is mainly assessed by these specialists on the basis of plant species, since these are readily observed. The presence and abundance of plant species that are scarce, or have important functional roles, emerged as important criteria for judging overall habitat quality. However, species defined as ‘positive indicator-species’ (not particularly scarce, but distinctive for the habitat) were considered particularly important. Scarce species are by definition not always found, and the presence of functionally important species is not a sufficient indicator of site quality. Habitat quality as assessed by the key informants was rank-correlated with the number of positive indicator-species present at a site for seven of the nine habitat classes assessed. Other metrics such as species-richness or a metric of scarcity were inconsistently or not correlated with the specialists’ assessments. We recommend that metrics of habitat quality used to assess N pollution impacts are based on the occurrence of, or habitat-suitability for, distinctive species. Metrics of this type are likely to be widely applicable for assessing habitat change in response to different drivers. The novel combined

Sound quality evaluation of air conditioning sound rating metric

NASA Astrophysics Data System (ADS)

Hodgdon, Kathleen K.; Peters, Jonathan A.; Burkhardt, Russell C.; Atchley, Anthony A.; Blood, Ingrid M.

2003-10-01

A product's success can depend on its acoustic signature as much as on the product's performance. The consumer's perception can strongly influence their satisfaction with and confidence in the product. A metric that can rate the content of the spectrum, and predict its consumer preference, is a valuable tool for manufacturers. The current method of assessing acoustic signatures from residential air conditioning units is defined in the Air Conditioning and Refrigeration Institute (ARI 270) 1995 Standard for Sound Rating of Outdoor Unitary Equipment. The ARI 270 metric, and modified versions of that metric, were implemented in software with the flexibility to modify the features applied. Numerous product signatures were analyzed to generate a set of synthesized spectra that targeted spectral configurations that challenged the metric's abilities. A subjective jury evaluation was conducted to establish the consumer preference for those spectra. Statistical correlations were conducted to assess the degree of relationship between the subjective preferences and the various metric calculations. Recommendations were made for modifications to improve the current metric's ability to predict subjective preference. [Research supported by the Air Conditioning and Refrigeration Institute.

Elementary Metric Curriculum - Project T.I.M.E. (Timely Implementation of Metric Education). Part I.

ERIC Educational Resources Information Center

Community School District 18, Brooklyn, NY.

This is a teacher's manual for an ISS-based elementary school course in the metric system. Behavioral objectives and student activities are included. The topics covered include: (1) linear measurement; (2) metric-decimal relationships; (3) metric conversions; (4) geometry; (5) scale drawings; and (6) capacity. This is the first of a two-part…

NEW CATEGORICAL METRICS FOR AIR QUALITY MODEL EVALUATION

EPA Science Inventory

Traditional categorical metrics used in model evaluations are "clear-cut" measures in that the model's ability to predict an exceedance is defined by a fixed threshold concentration and the metrics are defined by observation-forecast sets that are paired both in space and time. T...

Evaluating the Good Ontology Design Guideline (GoodOD) with the Ontology Quality Requirements and Evaluation Method and Metrics (OQuaRE)

PubMed Central

Duque-Ramos, Astrid; Boeker, Martin; Jansen, Ludger; Schulz, Stefan; Iniesta, Miguela; Fernández-Breis, Jesualdo Tomás

2014-01-01

Objective To (1) evaluate the GoodOD guideline for ontology development by applying the OQuaRE evaluation method and metrics to the ontology artefacts that were produced by students in a randomized controlled trial, and (2) informally compare the OQuaRE evaluation method with gold standard and competency questions based evaluation methods, respectively. Background In the last decades many methods for ontology construction and ontology evaluation have been proposed. However, none of them has become a standard and there is no empirical evidence of comparative evaluation of such methods. This paper brings together GoodOD and OQuaRE. GoodOD is a guideline for developing robust ontologies. It was previously evaluated in a randomized controlled trial employing metrics based on gold standard ontologies and competency questions as outcome parameters. OQuaRE is a method for ontology quality evaluation which adapts the SQuaRE standard for software product quality to ontologies and has been successfully used for evaluating the quality of ontologies. Methods In this paper, we evaluate the effect of training in ontology construction based on the GoodOD guideline within the OQuaRE quality evaluation framework and compare the results with those obtained for the previous studies based on the same data. Results Our results show a significant effect of the GoodOD training over developed ontologies by topics: (a) a highly significant effect was detected in three topics from the analysis of the ontologies of untrained and trained students; (b) both positive and negative training effects with respect to the gold standard were found for five topics. Conclusion The GoodOD guideline had a significant effect over the quality of the ontologies developed. Our results show that GoodOD ontologies can be effectively evaluated using OQuaRE and that OQuaRE is able to provide additional useful information about the quality of the GoodOD ontologies. PMID:25148262

Transfusion rate as a quality metric: is blood conservation a learnable skill?

PubMed

Paone, Gaetano; Brewer, Robert; Likosky, Donald S; Theurer, Patricia F; Bell, Gail F; Cogan, Chad M; Prager, Richard L

2013-10-01

Between January 2008 and December 2012, a multicenter quality collaborative initiated a focus on blood conservation as a quality metric, with educational presentations and quarterly reporting of institutional-level perioperative transfusion rates and outcomes. This prospective cohort study was undertaken to determine the effect of that initiative on transfusion rates after isolated coronary artery bypass grafting (CABG). Between January 1, 2008, and December 31, 2012, 30,271 patients underwent isolated CABG in Michigan. Evaluated were annual crude and adjusted trends in overall transfusion rates for red blood cells (RBCs), fresh frozen plasma (FFP), and platelets, and in operative death. Transfusion rates continuously decreased for all blood products. RBC use decreased from 56.4% in 2008 (baseline) to 38.3% in 2012, FFP use decreased from 14.8% to 9.1%, and platelet use decreased from 20.5% to 13.4% (ptrend < 0.001 for all). A significant reduction occurred in deep sternal wound infection, reoperation for bleeding, renal failure, prolonged ventilation, initial ventilator time, and intensive care unit duration. The percentage of patients discharged home significantly increased (ptrend < 0.001). Mortality rates did not differ significantly (ptrend = 0.11). In a multicenter quality collaborative, increased attention to transfusion-related outcomes and blood conservation techniques, coincident with regular reporting and review of perioperative transfusion rates as a quality metric, was associated with a significant decrease in blood product utilization. These reductions were concurrent with significant improvement in most perioperative outcomes. This intervention was also safe, as it was not associated with any increases in mortality. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

A priori discretization error metrics for distributed hydrologic modeling applications

NASA Astrophysics Data System (ADS)

Liu, Hongli; Tolson, Bryan A.; Craig, James R.; Shafii, Mahyar

2016-12-01

Watershed spatial discretization is an important step in developing a distributed hydrologic model. A key difficulty in the spatial discretization process is maintaining a balance between the aggregation-induced information loss and the increase in computational burden caused by the inclusion of additional computational units. Objective identification of an appropriate discretization scheme still remains a challenge, in part because of the lack of quantitative measures for assessing discretization quality, particularly prior to simulation. This study proposes a priori discretization error metrics to quantify the information loss of any candidate discretization scheme without having to run and calibrate a hydrologic model. These error metrics are applicable to multi-variable and multi-site discretization evaluation and provide directly interpretable information to the hydrologic modeler about discretization quality. The first metric, a subbasin error metric, quantifies the routing information loss from discretization, and the second, a hydrological response unit (HRU) error metric, improves upon existing a priori metrics by quantifying the information loss due to changes in land cover or soil type property aggregation. The metrics are straightforward to understand and easy to recode. Informed by the error metrics, a two-step discretization decision-making approach is proposed with the advantage of reducing extreme errors and meeting the user-specified discretization error targets. The metrics and decision-making approach are applied to the discretization of the Grand River watershed in Ontario, Canada. Results show that information loss increases as discretization gets coarser. Moreover, results help to explain the modeling difficulties associated with smaller upstream subbasins since the worst discretization errors and highest error variability appear in smaller upstream areas instead of larger downstream drainage areas. Hydrologic modeling experiments under

Holographic Spherically Symmetric Metrics

NASA Astrophysics Data System (ADS)

Petri, Michael

The holographic principle (HP) conjectures, that the maximum number of degrees of freedom of any realistic physical system is proportional to the system's boundary area. The HP has its roots in the study of black holes. It has recently been applied to cosmological solutions. In this article we apply the HP to spherically symmetric static space-times. We find that any regular spherically symmetric object saturating the HP is subject to tight constraints on the (interior) metric, energy-density, temperature and entropy-density. Whenever gravity can be described by a metric theory, gravity is macroscopically scale invariant and the laws of thermodynamics hold locally and globally, the (interior) metric of a regular holographic object is uniquely determined up to a constant factor and the interior matter-state must follow well defined scaling relations. When the metric theory of gravity is general relativity, the interior matter has an overall string equation of state (EOS) and a unique total energy-density. Thus the holographic metric derived in this article can serve as simple interior 4D realization of Mathur's string fuzzball proposal. Some properties of the holographic metric and its possible experimental verification are discussed. The geodesics of the holographic metric describe an isotropically expanding (or contracting) universe with a nearly homogeneous matter-distribution within the local Hubble volume. Due to the overall string EOS the active gravitational mass-density is zero, resulting in a coasting expansion with Ht = 1, which is compatible with the recent GRB-data.

Sigma metrics as a tool for evaluating the performance of internal quality control in a clinical chemistry laboratory.

PubMed

Kumar, B Vinodh; Mohan, Thuthi

2018-01-01

Six Sigma is one of the most popular quality management system tools employed for process improvement. The Six Sigma methods are usually applied when the outcome of the process can be measured. This study was done to assess the performance of individual biochemical parameters on a Sigma Scale by calculating the sigma metrics for individual parameters and to follow the Westgard guidelines for appropriate Westgard rules and levels of internal quality control (IQC) that needs to be processed to improve target analyte performance based on the sigma metrics. This is a retrospective study, and data required for the study were extracted between July 2015 and June 2016 from a Secondary Care Government Hospital, Chennai. The data obtained for the study are IQC - coefficient of variation percentage and External Quality Assurance Scheme (EQAS) - Bias% for 16 biochemical parameters. For the level 1 IQC, four analytes (alkaline phosphatase, magnesium, triglyceride, and high-density lipoprotein-cholesterol) showed an ideal performance of ≥6 sigma level, five analytes (urea, total bilirubin, albumin, cholesterol, and potassium) showed an average performance of <3 sigma level and for level 2 IQCs, same four analytes of level 1 showed a performance of ≥6 sigma level, and four analytes (urea, albumin, cholesterol, and potassium) showed an average performance of <3 sigma level. For all analytes <6 sigma level, the quality goal index (QGI) was <0.8 indicating the area requiring improvement to be imprecision except cholesterol whose QGI >1.2 indicated inaccuracy. This study shows that sigma metrics is a good quality tool to assess the analytical performance of a clinical chemistry laboratory. Thus, sigma metric analysis provides a benchmark for the laboratory to design a protocol for IQC, address poor assay performance, and assess the efficiency of existing laboratory processes.

Biotic, water-quality, and hydrologic metrics calculated for the analysis of temporal trends in National Water Quality Assessment Program Data in the Western United States

USGS Publications Warehouse

Wiele, Stephen M.; Brasher, Anne M.D.; Miller, Matthew P.; May, Jason T.; Carpenter, Kurt D.

2012-01-01

The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program was established by Congress in 1991 to collect long-term, nationally consistent information on the quality of the Nation's streams and groundwater. The NAWQA Program utilizes interdisciplinary and dynamic studies that link the chemical and physical conditions of streams (such as flow and habitat) with ecosystem health and the biologic condition of algae, aquatic invertebrates, and fish communities. This report presents metrics derived from NAWQA data and the U.S. Geological Survey streamgaging network for sampling sites in the Western United States, as well as associated chemical, habitat, and streamflow properties. The metrics characterize the conditions of algae, aquatic invertebrates, and fish. In addition, we have compiled climate records and basin characteristics related to the NAWQA sampling sites. The calculated metrics and compiled data can be used to analyze ecohydrologic trends over time.

MUSTANG: A Community-Facing Web Service to Improve Seismic Data Quality Awareness Through Metrics

NASA Astrophysics Data System (ADS)

Templeton, M. E.; Ahern, T. K.; Casey, R. E.; Sharer, G.; Weertman, B.; Ashmore, S.

2014-12-01

IRIS DMC is engaged in a new effort to provide broad and deep visibility into the quality of data and metadata found in its terabyte-scale geophysical data archive. Taking advantage of large and fast disk capacity, modern advances in open database technologies, and nimble provisioning of virtual machine resources, we are creating an openly accessible treasure trove of data measurements for scientists and the general public to utilize in providing new insights into the quality of this data. We have branded this statistical gathering system MUSTANG, and have constructed it as a component of the web services suite that IRIS DMC offers. MUSTANG measures over forty data metrics addressing issues with archive status, data statistics and continuity, signal anomalies, noise analysis, metadata checks, and station state of health. These metrics could potentially be used both by network operators to diagnose station problems and by data users to sort suitable data from unreliable or unusable data. Our poster details what MUSTANG is, how users can access it, what measurements they can find, and how MUSTANG fits into the IRIS DMC's data access ecosystem. Progress in data processing, approaches to data visualization, and case studies of MUSTANG's use for quality assurance will be presented. We want to illustrate what is possible with data quality assurance, the need for data quality assurance, and how the seismic community will benefit from this freely available analytics service.

Environmental Quality and Aquatic Invertebrate Metrics Relationships at Patagonian Wetlands Subjected to Livestock Grazing Pressures.

PubMed

Epele, Luis Beltrán; Miserendino, María Laura

2015-01-01

Livestock grazing can compromise the biotic integrity and health of wetlands, especially in remotes areas like Patagonia, which provide habitat for several endemic terrestrial and aquatic species. Understanding the effects of these land use practices on invertebrate communities can help prevent the deterioration of wetlands and provide insights for restoration. In this contribution, we assessed the responses of 36 metrics based on the structural and functional attributes of invertebrates (130 taxa) at 30 Patagonian wetlands that were subject to different levels of livestock grazing intensity. These levels were categorized as low, medium and high based on eight features (livestock stock densities plus seven wetland measurements). Significant changes in environmental features were detected across the gradient of wetlands, mainly related to pH, conductivity, and nutrient values. Regardless of rainfall gradient, symptoms of eutrophication were remarkable at some highly disturbed sites. Seven invertebrate metrics consistently and accurately responded to livestock grazing on wetlands. All of them were negatively related to increased levels of grazing disturbance, with the number of insect families appearing as the most robust measure. A multivariate approach (RDA) revealed that invertebrate metrics were significantly affected by environmental variables related to water quality: in particular, pH, conductivity, dissolved oxygen, nutrient concentrations, and the richness and coverage of aquatic plants. Our results suggest that the seven aforementioned metrics could be used to assess ecological quality in the arid and semi-arid wetlands of Patagonia, helping to ensure the creation of protected areas and their associated ecological services.

Environmental Quality and Aquatic Invertebrate Metrics Relationships at Patagonian Wetlands Subjected to Livestock Grazing Pressures

PubMed Central

2015-01-01

Livestock grazing can compromise the biotic integrity and health of wetlands, especially in remotes areas like Patagonia, which provide habitat for several endemic terrestrial and aquatic species. Understanding the effects of these land use practices on invertebrate communities can help prevent the deterioration of wetlands and provide insights for restoration. In this contribution, we assessed the responses of 36 metrics based on the structural and functional attributes of invertebrates (130 taxa) at 30 Patagonian wetlands that were subject to different levels of livestock grazing intensity. These levels were categorized as low, medium and high based on eight features (livestock stock densities plus seven wetland measurements). Significant changes in environmental features were detected across the gradient of wetlands, mainly related to pH, conductivity, and nutrient values. Regardless of rainfall gradient, symptoms of eutrophication were remarkable at some highly disturbed sites. Seven invertebrate metrics consistently and accurately responded to livestock grazing on wetlands. All of them were negatively related to increased levels of grazing disturbance, with the number of insect families appearing as the most robust measure. A multivariate approach (RDA) revealed that invertebrate metrics were significantly affected by environmental variables related to water quality: in particular, pH, conductivity, dissolved oxygen, nutrient concentrations, and the richness and coverage of aquatic plants. Our results suggest that the seven aforementioned metrics could be used to assess ecological quality in the arid and semi-arid wetlands of Patagonia, helping to ensure the creation of protected areas and their associated ecological services. PMID:26448652

Identification of metrics to monitor salt marsh integrity on National Wildlife Refuges in relation to conservation and management objectives

USGS Publications Warehouse

Neckles, Hilary A.; Guntenspergen, Glenn R.; Shriver, W. George; Danz, Nicholas P.; Wiest, Whitney A.; Nagel, Jessica L.; Olker, Jennifer H.

2013-01-01

Implementation of these metrics for quantitative assessment of NWRS salt marsh integrity in FWS Region 5 requires developing sampling designs for each refuge. Additionally, it is important to determine how the monitoring information will be used within a management context. SDM should be used to complete the analysis of salt marsh management decisions. The next steps would involve 1) prioritizing and weighting the management objectives; 2) predicting responses to individual management actions in terms of objectives and metrics; 3) using multiattribute utility theory to convert all measurable attributes to a common utility scale; 4) determining the total management benefit of each action by summing utilities across objectives; and 5) maximizing the total management benefits within cost constraints for each refuge. This process would allow the optimum management decisions for NWRS salt marshes to be selected and implemented based directly on monitoring data and current understanding of marsh responses to management actions. Monitoring the outcome of management actions would then allow new monitoring data to be incorporated into subsequent decisions. 

Establishing Qualitative Software Metrics in Department of the Navy Programs

DTIC Science & Technology

2015-10-29

dedicated to provide the highest quality software to its users. In doing, there is a need for a formalized set of Software Quality Metrics . The goal...of this paper is to establish the validity of those necessary Quality metrics . In our approach we collected the data of over a dozen programs...provide the necessary variable data for our formulas and tested the formulas for validity. Keywords: metrics ; software; quality I. PURPOSE Space

Distance Metric Tracking

DTIC Science & Technology

2016-03-02

some close- ness constant and dissimilar pairs be more distant than some larger constant. Online and non -linear extensions to the ITML methodology are...is obtained, instead of solving an objective function formed from the entire dataset. Many online learning methods have regret guarantees, that is... function Metric learning seeks to learn a metric that encourages data points marked as similar to be close and data points marked as different to be far

The role of complexity metrics in a multi-institutional dosimetry audit of VMAT

PubMed Central

Agnew, Christina E; Hussein, Mohammad; Tsang, Yatman; McWilliam, Alan; Hounsell, Alan R; Clark, Catharine H

2016-01-01

Objective: To demonstrate the benefit of complexity metrics such as the modulation complexity score (MCS) and monitor units (MUs) in multi-institutional audits of volumetric-modulated arc therapy (VMAT) delivery. Methods: 39 VMAT treatment plans were analysed using MCS and MU. A virtual phantom planning exercise was planned and independently measured using the PTW Octavius® phantom and seven29® 2D array (PTW-Freiburg GmbH, Freiburg, Germany). MCS and MU were compared with the median gamma index pass rates (2%/2 and 3%/3 mm) and plan quality. The treatment planning systems (TPS) were grouped by VMAT modelling being specifically designed for the linear accelerator manufacturer's own treatment delivery system (Type 1) or independent of vendor for VMAT delivery (Type 2). Differences in plan complexity (MCS and MU) between TPS types were compared. Results: For Varian® linear accelerators (Varian® Medical Systems, Inc., Palo Alto, CA), MCS and MU were significantly correlated with gamma pass rates. Type 2 TPS created poorer quality, more complex plans with significantly higher MUs and MCS than Type 1 TPS. Plan quality was significantly correlated with MU for Type 2 plans. A statistically significant correlation was observed between MU and MCS for all plans (R = −0.84, p < 0.01). Conclusion: MU and MCS have a role in assessing plan complexity in audits along with plan quality metrics. Plan complexity metrics give some indication of plan deliverability but should be analysed with plan quality. Advances in knowledge: Complexity metrics were investigated for a national rotational audit involving 34 institutions and they showed value. The metrics found that more complex plans were created for planning systems which were independent of vendor for VMAT delivery. PMID:26511276

Healthy Volunteer 2020: Comparing Peace Corps Volunteers' health metrics with Healthy People 2020 national objectives.

PubMed

Henderson, Susan J; Newman, Jeannette; Ferguson, Rennie W; Jung, Paul

2016-12-01

Healthy People 2020 (HP2020) provides a set of quantifiable objectives for improving the health and well-being of Americans. This study examines Peace Corps Volunteers' health metrics in comparison with the Leading Health Indicators (LHIs) in order to set baseline measures for Volunteers' health care and align our measurements with Healthy People 2020 standards. Health data from multiple internal Peace Corps datasets were compared with relevant LHIs and analyzed using descriptive statistics. Seventeen (65%) of the 26 LHIs were relevant to Peace Corps Volunteers. Of these, Volunteers' health measures met or were more favorable than the goals of 13 (76%) of the LHIs. There were no data available for 4 (24%) of the LHIs. The entire Volunteer population has full access to primary care, oral health, and reproductive health services. No suicides or homicides were reported among Volunteers during the analyzed time period. Utilizing the LHIs, we have identified high-priority public health issues relevant for the Peace Corps Volunteer population. We discuss the need for quality data to measure and monitor Volunteers' health progress and outcomes over time, and also to standardize our measurements with Healthy People 2020 benchmarks. This framework may foster greater collaboration to engage in health promotion and disease prevention activities driven by evidence-based information, which may, in turn, encourage healthy behavior among Volunteers.

Candidate control design metrics for an agile fighter

NASA Technical Reports Server (NTRS)

Murphy, Patrick C.; Bailey, Melvin L.; Ostroff, Aaron J.

1991-01-01

Success in the fighter combat environment of the future will certainly demand increasing capability from aircraft technology. These advanced capabilities in the form of superagility and supermaneuverability will require special design techniques which translate advanced air combat maneuvering requirements into design criteria. Control design metrics can provide some of these techniques for the control designer. Thus study presents an overview of control design metrics and investigates metrics for advanced fighter agility. The objectives of various metric users, such as airframe designers and pilots, are differentiated from the objectives of the control designer. Using an advanced fighter model, metric values are documented over a portion of the flight envelope through piloted simulation. These metric values provide a baseline against which future control system improvements can be compared and against which a control design methodology can be developed. Agility is measured for axial, pitch, and roll axes. Axial metrics highlight acceleration and deceleration capabilities under different flight loads and include specific excess power measurements to characterize energy meneuverability. Pitch metrics cover both body-axis and wind-axis pitch rates and accelerations. Included in pitch metrics are nose pointing metrics which highlight displacement capability between the nose and the velocity vector. Roll metrics (or torsion metrics) focus on rotational capability about the wind axis.

Surveillance metrics sensitivity study.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamada, Michael S.; Bierbaum, Rene Lynn; Robertson, Alix A.

2011-09-01

In September of 2009, a Tri-Lab team was formed to develop a set of metrics relating to the NNSA nuclear weapon surveillance program. The purpose of the metrics was to develop a more quantitative and/or qualitative metric(s) describing the results of realized or non-realized surveillance activities on our confidence in reporting reliability and assessing the stockpile. As a part of this effort, a statistical sub-team investigated various techniques and developed a complementary set of statistical metrics that could serve as a foundation for characterizing aspects of meeting the surveillance program objectives. The metrics are a combination of tolerance limit calculationsmore » and power calculations, intending to answer level-of-confidence type questions with respect to the ability to detect certain undesirable behaviors (catastrophic defects, margin insufficiency defects, and deviations from a model). Note that the metrics are not intended to gauge product performance but instead the adequacy of surveillance. This report gives a short description of four metrics types that were explored and the results of a sensitivity study conducted to investigate their behavior for various inputs. The results of the sensitivity study can be used to set the risk parameters that specify the level of stockpile problem that the surveillance program should be addressing.« less

Surveillance Metrics Sensitivity Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bierbaum, R; Hamada, M; Robertson, A

2011-11-01

In September of 2009, a Tri-Lab team was formed to develop a set of metrics relating to the NNSA nuclear weapon surveillance program. The purpose of the metrics was to develop a more quantitative and/or qualitative metric(s) describing the results of realized or non-realized surveillance activities on our confidence in reporting reliability and assessing the stockpile. As a part of this effort, a statistical sub-team investigated various techniques and developed a complementary set of statistical metrics that could serve as a foundation for characterizing aspects of meeting the surveillance program objectives. The metrics are a combination of tolerance limit calculationsmore » and power calculations, intending to answer level-of-confidence type questions with respect to the ability to detect certain undesirable behaviors (catastrophic defects, margin insufficiency defects, and deviations from a model). Note that the metrics are not intended to gauge product performance but instead the adequacy of surveillance. This report gives a short description of four metrics types that were explored and the results of a sensitivity study conducted to investigate their behavior for various inputs. The results of the sensitivity study can be used to set the risk parameters that specify the level of stockpile problem that the surveillance program should be addressing.« less

Metrics Handbook (Air Force Systems Command)

NASA Astrophysics Data System (ADS)

1991-08-01

The handbook is designed to help one develop and use good metrics. It is intended to provide sufficient information to begin developing metrics for objectives, processes, and tasks, and to steer one toward appropriate actions based on the data one collects. It should be viewed as a road map to assist one in arriving at meaningful metrics and to assist in continuous process improvement.

Multi Objective Optimization of Yarn Quality and Fibre Quality Using Evolutionary Algorithm

NASA Astrophysics Data System (ADS)

Ghosh, Anindya; Das, Subhasis; Banerjee, Debamalya

2013-03-01

The quality and cost of resulting yarn play a significant role to determine its end application. The challenging task of any spinner lies in producing a good quality yarn with added cost benefit. The present work does a multi-objective optimization on two objectives, viz. maximization of cotton yarn strength and minimization of raw material quality. The first objective function has been formulated based on the artificial neural network input-output relation between cotton fibre properties and yarn strength. The second objective function is formulated with the well known regression equation of spinning consistency index. It is obvious that these two objectives are conflicting in nature i.e. not a single combination of cotton fibre parameters does exist which produce maximum yarn strength and minimum cotton fibre quality simultaneously. Therefore, it has several optimal solutions from which a trade-off is needed depending upon the requirement of user. In this work, the optimal solutions are obtained with an elitist multi-objective evolutionary algorithm based on Non-dominated Sorting Genetic Algorithm II (NSGA-II). These optimum solutions may lead to the efficient exploitation of raw materials to produce better quality yarns at low costs.

How to Teach Metric Now.

ERIC Educational Resources Information Center

Worcester Public Schools, MA.

This curriculum guide for grades K-6 was prepared to assist teachers and students in learning about the metric system. An introductory section presents a brief history of the metric system and the rationale for introducing it into the schools. Instructional objectives and suggested learning activities are presented for each grade level. The…

Metrical Phonology: German Sound System.

ERIC Educational Resources Information Center

Tice, Bradley S.

Metrical phonology, a linguistic process of phonological stress assessment and diagrammatic simplification of sentence and word stress, is discussed as it is found in the English and German languages. The objective is to promote use of metrical phonology as a tool for enhancing instruction in stress patterns in words and sentences, particularly in…

Saving Educational Dollars through Quality Objectives.

ERIC Educational Resources Information Center

Alvir, Howard P.

This document is a collection of working papers written to meet the specific needs of teachers who are starting to think about and write performance objectives. It emphasizes qualitative objectives as opposed to quantitative classroom goals. The author describes quality objectives as marked by their clarity, accessibility, accountability, and…

Automating Software Design Metrics.

DTIC Science & Technology

1984-02-01

INTRODUCTION 1 ", ... 0..1 1.2 HISTORICAL PERSPECTIVE High quality software is of interest to both the software engineering com- munity and its users. As...contributions of many other software engineering efforts, most notably [MCC 77] and [Boe 83b], which have defined and refined a framework for quantifying...AUTOMATION OF DESIGN METRICS Software metrics can be useful within the context of an integrated soft- ware engineering environment. The purpose of this

Elementary Metric Curriculum - Project T.I.M.E. (Timely Implementation of Metric Education). Part II.

ERIC Educational Resources Information Center

Community School District 18, Brooklyn, NY.

This is the second part of a two-part teacher's manual for an ISS-based elementary school course in the metric system. Behavioral objectives and student activities are included. Topics include: (1) capacity; (2) calculation of volume and surface area of cylinders and cones; (3) mass; (4) temperature; and (5) metric conversions. (BB)

A condition metric for Eucalyptus woodland derived from expert evaluations.

PubMed

Sinclair, Steve J; Bruce, Matthew J; Griffioen, Peter; Dodd, Amanda; White, Matthew D

2018-02-01

The evaluation of ecosystem quality is important for land-management and land-use planning. Evaluation is unavoidably subjective, and robust metrics must be based on consensus and the structured use of observations. We devised a transparent and repeatable process for building and testing ecosystem metrics based on expert data. We gathered quantitative evaluation data on the quality of hypothetical grassy woodland sites from experts. We used these data to train a model (an ensemble of 30 bagged regression trees) capable of predicting the perceived quality of similar hypothetical woodlands based on a set of 13 site variables as inputs (e.g., cover of shrubs, richness of native forbs). These variables can be measured at any site and the model implemented in a spreadsheet as a metric of woodland quality. We also investigated the number of experts required to produce an opinion data set sufficient for the construction of a metric. The model produced evaluations similar to those provided by experts, as shown by assessing the model's quality scores of expert-evaluated test sites not used to train the model. We applied the metric to 13 woodland conservation reserves and asked managers of these sites to independently evaluate their quality. To assess metric performance, we compared the model's evaluation of site quality with the managers' evaluations through multidimensional scaling. The metric performed relatively well, plotting close to the center of the space defined by the evaluators. Given the method provides data-driven consensus and repeatability, which no single human evaluator can provide, we suggest it is a valuable tool for evaluating ecosystem quality in real-world contexts. We believe our approach is applicable to any ecosystem. © 2017 State of Victoria.

Quality assessment of color images based on the measure of just noticeable color difference

NASA Astrophysics Data System (ADS)

Chou, Chun-Hsien; Hsu, Yun-Hsiang

2014-01-01

Accurate assessment on the quality of color images is an important step to many image processing systems that convey visual information of the reproduced images. An accurate objective image quality assessment (IQA) method is expected to give the assessment result highly agreeing with the subjective assessment. To assess the quality of color images, many approaches simply apply the metric for assessing the quality of gray scale images to each of three color channels of the color image, neglecting the correlation among three color channels. In this paper, a metric for assessing color images' quality is proposed, in which the model of variable just-noticeable color difference (VJNCD) is employed to estimate the visibility thresholds of distortion inherent in each color pixel. With the estimated visibility thresholds of distortion, the proposed metric measures the average perceptible distortion in terms of the quantized distortion according to the perceptual error map similar to that defined by National Bureau of Standards (NBS) for converting the color difference enumerated by CIEDE2000 to the objective score of perceptual quality assessment. The perceptual error map in this case is designed for each pixel according to the visibility threshold estimated by the VJNCD model. The performance of the proposed metric is verified by assessing the test images in the LIVE database, and is compared with those of many well-know IQA metrics. Experimental results indicate that the proposed metric is an effective IQA method that can accurately predict the image quality of color images in terms of the correlation between objective scores and subjective evaluation.

Requirement Metrics for Risk Identification

NASA Technical Reports Server (NTRS)

Hammer, Theodore; Huffman, Lenore; Wilson, William; Rosenberg, Linda; Hyatt, Lawrence

1996-01-01

The Software Assurance Technology Center (SATC) is part of the Office of Mission Assurance of the Goddard Space Flight Center (GSFC). The SATC's mission is to assist National Aeronautics and Space Administration (NASA) projects to improve the quality of software which they acquire or develop. The SATC's efforts are currently focused on the development and use of metric methodologies and tools that identify and assess risks associated with software performance and scheduled delivery. This starts at the requirements phase, where the SATC, in conjunction with software projects at GSFC and other NASA centers is working to identify tools and metric methodologies to assist project managers in identifying and mitigating risks. This paper discusses requirement metrics currently being used at NASA in a collaborative effort between the SATC and the Quality Assurance Office at GSFC to utilize the information available through the application of requirements management tools.

The use of vision-based image quality metrics to predict low-light performance of camera phones

NASA Astrophysics Data System (ADS)

Hultgren, B.; Hertel, D.

2010-01-01

Small digital camera modules such as those in mobile phones have become ubiquitous. Their low-light performance is of utmost importance since a high percentage of images are made under low lighting conditions where image quality failure may occur due to blur, noise, and/or underexposure. These modes of image degradation are not mutually exclusive: they share common roots in the physics of the imager, the constraints of image processing, and the general trade-off situations in camera design. A comprehensive analysis of failure modes is needed in order to understand how their interactions affect overall image quality. Low-light performance is reported for DSLR, point-and-shoot, and mobile phone cameras. The measurements target blur, noise, and exposure error. Image sharpness is evaluated from three different physical measurements: static spatial frequency response, handheld motion blur, and statistical information loss due to image processing. Visual metrics for sharpness, graininess, and brightness are calculated from the physical measurements, and displayed as orthogonal image quality metrics to illustrate the relative magnitude of image quality degradation as a function of subject illumination. The impact of each of the three sharpness measurements on overall sharpness quality is displayed for different light levels. The power spectrum of the statistical information target is a good representation of natural scenes, thus providing a defined input signal for the measurement of power-spectrum based signal-to-noise ratio to characterize overall imaging performance.

Understanding Acceptance of Software Metrics--A Developer Perspective

ERIC Educational Resources Information Center

Umarji, Medha

2009-01-01

Software metrics are measures of software products and processes. Metrics are widely used by software organizations to help manage projects, improve product quality and increase efficiency of the software development process. However, metrics programs tend to have a high failure rate in organizations, and developer pushback is one of the sources…

NASA Aviation Safety Program Systems Analysis/Program Assessment Metrics Review

NASA Technical Reports Server (NTRS)

Louis, Garrick E.; Anderson, Katherine; Ahmad, Tisan; Bouabid, Ali; Siriwardana, Maya; Guilbaud, Patrick

2003-01-01

The goal of this project is to evaluate the metrics and processes used by NASA's Aviation Safety Program in assessing technologies that contribute to NASA's aviation safety goals. There were three objectives for reaching this goal. First, NASA's main objectives for aviation safety were documented and their consistency was checked against the main objectives of the Aviation Safety Program. Next, the metrics used for technology investment by the Program Assessment function of AvSP were evaluated. Finally, other metrics that could be used by the Program Assessment Team (PAT) were identified and evaluated. This investigation revealed that the objectives are in fact consistent across organizational levels at NASA and with the FAA. Some of the major issues discussed in this study which should be further investigated, are the removal of the Cost and Return-on-Investment metrics, the lack of the metrics to measure the balance of investment and technology, the interdependencies between some of the metric risk driver categories, and the conflict between 'fatal accident rate' and 'accident rate' in the language of the Aviation Safety goal as stated in different sources.

WATER QUALITY VULNERABILITY IN THE OZARKS USING LANDSCAPE ECOLOGY METRICS: UPPER WHITE RIVER BROWSER (V2.0)

EPA Science Inventory

The principal focus of this project is the mapping and interpretation of landscape scale (i.e., broad scale) ecological metrics among contributing watersheds of the Upper White River, and the development of geospatial models of water quality vulnerability for several suspected no...

Objective assessment of MPEG-2 video quality

NASA Astrophysics Data System (ADS)

Gastaldo, Paolo; Zunino, Rodolfo; Rovetta, Stefano

2002-07-01

The increasing use of video compression standards in broadcasting television systems has required, in recent years, the development of video quality measurements that take into account artifacts specifically caused by digital compression techniques. In this paper we present a methodology for the objective quality assessment of MPEG video streams by using circular back-propagation feedforward neural networks. Mapping neural networks can render nonlinear relationships between objective features and subjective judgments, thus avoiding any simplifying assumption on the complexity of the model. The neural network processes an instantaneous set of input values, and yields an associated estimate of perceived quality. Therefore, the neural-network approach turns objective quality assessment into adaptive modeling of subjective perception. The objective features used for the estimate are chosen according to the assessed relevance to perceived quality and are continuously extracted in real time from compressed video streams. The overall system mimics perception but does not require any analytical model of the underlying physical phenomenon. The capability to process compressed video streams represents an important advantage over existing approaches, like avoiding the stream-decoding process greatly enhances real-time performance. Experimental results confirm that the system provides satisfactory, continuous-time approximations for actual scoring curves concerning real test videos.

Bootstrap Signal-to-Noise Confidence Intervals: An Objective Method for Subject Exclusion and Quality Control in ERP Studies

PubMed Central

Parks, Nathan A.; Gannon, Matthew A.; Long, Stephanie M.; Young, Madeleine E.

2016-01-01

Analysis of event-related potential (ERP) data includes several steps to ensure that ERPs meet an appropriate level of signal quality. One such step, subject exclusion, rejects subject data if ERP waveforms fail to meet an appropriate level of signal quality. Subject exclusion is an important quality control step in the ERP analysis pipeline as it ensures that statistical inference is based only upon those subjects exhibiting clear evoked brain responses. This critical quality control step is most often performed simply through visual inspection of subject-level ERPs by investigators. Such an approach is qualitative, subjective, and susceptible to investigator bias, as there are no standards as to what constitutes an ERP of sufficient signal quality. Here, we describe a standardized and objective method for quantifying waveform quality in individual subjects and establishing criteria for subject exclusion. The approach uses bootstrap resampling of ERP waveforms (from a pool of all available trials) to compute a signal-to-noise ratio confidence interval (SNR-CI) for individual subject waveforms. The lower bound of this SNR-CI (SNRLB) yields an effective and objective measure of signal quality as it ensures that ERP waveforms statistically exceed a desired signal-to-noise criterion. SNRLB provides a quantifiable metric of individual subject ERP quality and eliminates the need for subjective evaluation of waveform quality by the investigator. We detail the SNR-CI methodology, establish the efficacy of employing this approach with Monte Carlo simulations, and demonstrate its utility in practice when applied to ERP datasets. PMID:26903849

A priori discretization quality metrics for distributed hydrologic modeling applications

NASA Astrophysics Data System (ADS)

Liu, Hongli; Tolson, Bryan; Craig, James; Shafii, Mahyar; Basu, Nandita

2016-04-01

In distributed hydrologic modelling, a watershed is treated as a set of small homogeneous units that address the spatial heterogeneity of the watershed being simulated. The ability of models to reproduce observed spatial patterns firstly depends on the spatial discretization, which is the process of defining homogeneous units in the form of grid cells, subwatersheds, or hydrologic response units etc. It is common for hydrologic modelling studies to simply adopt a nominal or default discretization strategy without formally assessing alternative discretization levels. This approach lacks formal justifications and is thus problematic. More formalized discretization strategies are either a priori or a posteriori with respect to building and running a hydrologic simulation model. A posteriori approaches tend to be ad-hoc and compare model calibration and/or validation performance under various watershed discretizations. The construction and calibration of multiple versions of a distributed model can become a seriously limiting computational burden. Current a priori approaches are more formalized and compare overall heterogeneity statistics of dominant variables between candidate discretization schemes and input data or reference zones. While a priori approaches are efficient and do not require running a hydrologic model, they do not fully investigate the internal spatial pattern changes of variables of interest. Furthermore, the existing a priori approaches focus on landscape and soil data and do not assess impacts of discretization on stream channel definition even though its significance has been noted by numerous studies. The primary goals of this study are to (1) introduce new a priori discretization quality metrics considering the spatial pattern changes of model input data; (2) introduce a two-step discretization decision-making approach to compress extreme errors and meet user-specified discretization expectations through non-uniform discretization threshold

RNA-SeQC: RNA-seq metrics for quality control and process optimization.

PubMed

DeLuca, David S; Levin, Joshua Z; Sivachenko, Andrey; Fennell, Timothy; Nazaire, Marc-Danie; Williams, Chris; Reich, Michael; Winckler, Wendy; Getz, Gad

2012-06-01

RNA-seq, the application of next-generation sequencing to RNA, provides transcriptome-wide characterization of cellular activity. Assessment of sequencing performance and library quality is critical to the interpretation of RNA-seq data, yet few tools exist to address this issue. We introduce RNA-SeQC, a program which provides key measures of data quality. These metrics include yield, alignment and duplication rates; GC bias, rRNA content, regions of alignment (exon, intron and intragenic), continuity of coverage, 3'/5' bias and count of detectable transcripts, among others. The software provides multi-sample evaluation of library construction protocols, input materials and other experimental parameters. The modularity of the software enables pipeline integration and the routine monitoring of key measures of data quality such as the number of alignable reads, duplication rates and rRNA contamination. RNA-SeQC allows investigators to make informed decisions about sample inclusion in downstream analysis. In summary, RNA-SeQC provides quality control measures critical to experiment design, process optimization and downstream computational analysis. See www.genepattern.org to run online, or www.broadinstitute.org/rna-seqc/ for a command line tool.

Metrics and the effective computational scientist: process, quality and communication.

PubMed

Baldwin, Eric T

2012-09-01

Recent treatments of computational knowledge worker productivity have focused upon the value the discipline brings to drug discovery using positive anecdotes. While this big picture approach provides important validation of the contributions of these knowledge workers, the impact accounts do not provide the granular detail that can help individuals and teams perform better. I suggest balancing the impact-focus with quantitative measures that can inform the development of scientists. Measuring the quality of work, analyzing and improving processes, and the critical evaluation of communication can provide immediate performance feedback. The introduction of quantitative measures can complement the longer term reporting of impacts on drug discovery. These metric data can document effectiveness trends and can provide a stronger foundation for the impact dialogue. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simulation of devices mobility to estimate wireless channel quality metrics in 5G networks

NASA Astrophysics Data System (ADS)

Orlov, Yu.; Fedorov, S.; Samuylov, A.; Gaidamaka, Yu.; Molchanov, D.

2017-07-01

The problem of channel quality estimation for devices in a wireless 5G network is formulated. As a performance metrics of interest we choose the signal-to-interference-plus-noise ratio, which depends essentially on the distance between the communicating devices. A model with a plurality of moving devices in a bounded three-dimensional space and a simulation algorithm to determine the distances between the devices for a given motion model are devised.

App Usage Factor: A Simple Metric to Compare the Population Impact of Mobile Medical Apps

PubMed Central

Wyatt, Jeremy C

2015-01-01

Background One factor when assessing the quality of mobile apps is quantifying the impact of a given app on a population. There is currently no metric which can be used to compare the population impact of a mobile app across different health care disciplines. Objective The objective of this study is to create a novel metric to characterize the impact of a mobile app on a population. Methods We developed the simple novel metric, app usage factor (AUF), defined as the logarithm of the product of the number of active users of a mobile app with the median number of daily uses of the app. The behavior of this metric was modeled using simulated modeling in Python, a general-purpose programming language. Three simulations were conducted to explore the temporal and numerical stability of our metric and a simulated app ecosystem model using a simulated dataset of 20,000 apps. Results Simulations confirmed the metric was stable between predicted usage limits and remained stable at extremes of these limits. Analysis of a simulated dataset of 20,000 apps calculated an average value for the app usage factor of 4.90 (SD 0.78). A temporal simulation showed that the metric remained stable over time and suitable limits for its use were identified. Conclusions A key component when assessing app risk and potential harm is understanding the potential population impact of each mobile app. Our metric has many potential uses for a wide range of stakeholders in the app ecosystem, including users, regulators, developers, and health care professionals. Furthermore, this metric forms part of the overall estimate of risk and potential for harm or benefit posed by a mobile medical app. We identify the merits and limitations of this metric, as well as potential avenues for future validation and research. PMID:26290093

Handbook of Classroom and Workshop Metric Activity Stations.

ERIC Educational Resources Information Center

Illinois State Office of Education, Springfield.

The objectives of this handbook are to assist K-8 classroom teachers in launching an activity-oriented metric program that provides learning experiences in the measurement strands of linear, mass, and temperature, and to assist metric coordinators in planning metric awareness workshops for teachers, parents, and various community organizations.…

Development and application of a novel metric to assess effectiveness of biomedical data

PubMed Central

Bloom, Gregory C; Eschrich, Steven; Hang, Gang; Schabath, Matthew B; Bhansali, Neera; Hoerter, Andrew M; Morgan, Scott; Fenstermacher, David A

2013-01-01

Objective Design a metric to assess the comparative effectiveness of biomedical data elements within a study that incorporates their statistical relatedness to a given outcome variable as well as a measurement of the quality of their underlying data. Materials and methods The cohort consisted of 874 patients with adenocarcinoma of the lung, each with 47 clinical data elements. The p value for each element was calculated using the Cox proportional hazard univariable regression model with overall survival as the endpoint. An attribute or A-score was calculated by quantification of an element's four quality attributes; Completeness, Comprehensiveness, Consistency and Overall-cost. An effectiveness or E-score was obtained by calculating the conditional probabilities of the p-value and A-score within the given data set with their product equaling the effectiveness score (E-score). Results The E-score metric provided information about the utility of an element beyond an outcome-related p value ranking. E-scores for elements age-at-diagnosis, gender and tobacco-use showed utility above what their respective p values alone would indicate due to their relative ease of acquisition, that is, higher A-scores. Conversely, elements surgery-site, histologic-type and pathological-TNM stage were down-ranked in comparison to their p values based on lower A-scores caused by significantly higher acquisition costs. Conclusions A novel metric termed E-score was developed which incorporates standard statistics with data quality metrics and was tested on elements from a large lung cohort. Results show that an element's underlying data quality is an important consideration in addition to p value correlation to outcome when determining the element's clinical or research utility in a study. PMID:23975264

Bibliometrics: tracking research impact by selecting the appropriate metrics.

PubMed

Agarwal, Ashok; Durairajanayagam, Damayanthi; Tatagari, Sindhuja; Esteves, Sandro C; Harlev, Avi; Henkel, Ralf; Roychoudhury, Shubhadeep; Homa, Sheryl; Puchalt, Nicolás Garrido; Ramasamy, Ranjith; Majzoub, Ahmad; Ly, Kim Dao; Tvrda, Eva; Assidi, Mourad; Kesari, Kavindra; Sharma, Reecha; Banihani, Saleem; Ko, Edmund; Abu-Elmagd, Muhammad; Gosalvez, Jaime; Bashiri, Asher

2016-01-01

Traditionally, the success of a researcher is assessed by the number of publications he or she publishes in peer-reviewed, indexed, high impact journals. This essential yardstick, often referred to as the impact of a specific researcher, is assessed through the use of various metrics. While researchers may be acquainted with such matrices, many do not know how to use them to enhance their careers. In addition to these metrics, a number of other factors should be taken into consideration to objectively evaluate a scientist's profile as a researcher and academician. Moreover, each metric has its own limitations that need to be considered when selecting an appropriate metric for evaluation. This paper provides a broad overview of the wide array of metrics currently in use in academia and research. Popular metrics are discussed and defined, including traditional metrics and article-level metrics, some of which are applied to researchers for a greater understanding of a particular concept, including varicocele that is the thematic area of this Special Issue of Asian Journal of Andrology. We recommend the combined use of quantitative and qualitative evaluation using judiciously selected metrics for a more objective assessment of scholarly output and research impact.

Objective quality assessment for multiexposure multifocus image fusion.

PubMed

Hassen, Rania; Wang, Zhou; Salama, Magdy M A

2015-09-01

There has been a growing interest in image fusion technologies, but how to objectively evaluate the quality of fused images has not been fully understood. Here, we propose a method for objective quality assessment of multiexposure multifocus image fusion based on the evaluation of three key factors of fused image quality: 1) contrast preservation; 2) sharpness; and 3) structure preservation. Subjective experiments are conducted to create an image fusion database, based on which, performance evaluation shows that the proposed fusion quality index correlates well with subjective scores, and gives a significant improvement over the existing fusion quality measures.

Coverage Metrics for Requirements-Based Testing: Evaluation of Effectiveness

NASA Technical Reports Server (NTRS)

Staats, Matt; Whalen, Michael W.; Heindahl, Mats P. E.; Rajan, Ajitha

2010-01-01

In black-box testing, the tester creates a set of tests to exercise a system under test without regard to the internal structure of the system. Generally, no objective metric is used to measure the adequacy of black-box tests. In recent work, we have proposed three requirements coverage metrics, allowing testers to objectively measure the adequacy of a black-box test suite with respect to a set of requirements formalized as Linear Temporal Logic (LTL) properties. In this report, we evaluate the effectiveness of these coverage metrics with respect to fault finding. Specifically, we conduct an empirical study to investigate two questions: (1) do test suites satisfying a requirements coverage metric provide better fault finding than randomly generated test suites of approximately the same size?, and (2) do test suites satisfying a more rigorous requirements coverage metric provide better fault finding than test suites satisfying a less rigorous requirements coverage metric? Our results indicate (1) only one coverage metric proposed -- Unique First Cause (UFC) coverage -- is sufficiently rigorous to ensure test suites satisfying the metric outperform randomly generated test suites of similar size and (2) that test suites satisfying more rigorous coverage metrics provide better fault finding than test suites satisfying less rigorous coverage metrics.

Health impact metrics for air pollution management strategies

PubMed Central

Martenies, Sheena E.; Wilkins, Donele; Batterman, Stuart A.

2015-01-01

Health impact assessments (HIAs) inform policy and decision making by providing information regarding future health concerns, and quantitative HIAs now are being used for local and urban-scale projects. HIA results can be expressed using a variety of metrics that differ in meaningful ways, and guidance is lacking with respect to best practices for the development and use of HIA metrics. This study reviews HIA metrics pertaining to air quality management and presents evaluative criteria for their selection and use. These are illustrated in a case study where PM2.5 concentrations are lowered from 10 to 8 µg/m3 in an urban area of 1.8 million people. Health impact functions are used to estimate the number of premature deaths, unscheduled hospitalizations and other morbidity outcomes. The most common metric in recent quantitative HIAs has been the number of cases of adverse outcomes avoided. Other metrics include time-based measures, e.g., disability-adjusted life years (DALYs), monetized impacts, functional-unit based measures, e.g., benefits per ton of emissions reduced, and other economic indicators, e.g., cost-benefit ratios. These metrics are evaluated by considering their comprehensiveness, the spatial and temporal resolution of the analysis, how equity considerations are facilitated, and the analysis and presentation of uncertainty. In the case study, the greatest number of avoided cases occurs for low severity morbidity outcomes, e.g., asthma exacerbations (n=28,000) and minor-restricted activity days (n=37,000); while DALYs and monetized impacts are driven by the severity, duration and value assigned to a relatively low number of premature deaths (n=190 to 230 per year). The selection of appropriate metrics depends on the problem context and boundaries, the severity of impacts, and community values regarding health. The number of avoided cases provides an estimate of the number of people affected, and monetized impacts facilitate additional economic analyses

Health impact metrics for air pollution management strategies.

PubMed

Martenies, Sheena E; Wilkins, Donele; Batterman, Stuart A

2015-12-01

Health impact assessments (HIAs) inform policy and decision making by providing information regarding future health concerns, and quantitative HIAs now are being used for local and urban-scale projects. HIA results can be expressed using a variety of metrics that differ in meaningful ways, and guidance is lacking with respect to best practices for the development and use of HIA metrics. This study reviews HIA metrics pertaining to air quality management and presents evaluative criteria for their selection and use. These are illustrated in a case study where PM2.5 concentrations are lowered from 10 to 8μg/m(3) in an urban area of 1.8 million people. Health impact functions are used to estimate the number of premature deaths, unscheduled hospitalizations and other morbidity outcomes. The most common metric in recent quantitative HIAs has been the number of cases of adverse outcomes avoided. Other metrics include time-based measures, e.g., disability-adjusted life years (DALYs), monetized impacts, functional-unit based measures, e.g., benefits per ton of emissions reduced, and other economic indicators, e.g., cost-benefit ratios. These metrics are evaluated by considering their comprehensiveness, the spatial and temporal resolution of the analysis, how equity considerations are facilitated, and the analysis and presentation of uncertainty. In the case study, the greatest number of avoided cases occurs for low severity morbidity outcomes, e.g., asthma exacerbations (n=28,000) and minor-restricted activity days (n=37,000); while DALYs and monetized impacts are driven by the severity, duration and value assigned to a relatively low number of premature deaths (n=190 to 230 per year). The selection of appropriate metrics depends on the problem context and boundaries, the severity of impacts, and community values regarding health. The number of avoided cases provides an estimate of the number of people affected, and monetized impacts facilitate additional economic analyses

Constrained Metric Learning by Permutation Inducing Isometries.

PubMed

Bosveld, Joel; Mahmood, Arif; Huynh, Du Q; Noakes, Lyle

2016-01-01

The choice of metric critically affects the performance of classification and clustering algorithms. Metric learning algorithms attempt to improve performance, by learning a more appropriate metric. Unfortunately, most of the current algorithms learn a distance function which is not invariant to rigid transformations of images. Therefore, the distances between two images and their rigidly transformed pair may differ, leading to inconsistent classification or clustering results. We propose to constrain the learned metric to be invariant to the geometry preserving transformations of images that induce permutations in the feature space. The constraint that these transformations are isometries of the metric ensures consistent results and improves accuracy. Our second contribution is a dimension reduction technique that is consistent with the isometry constraints. Our third contribution is the formulation of the isometry constrained logistic discriminant metric learning (IC-LDML) algorithm, by incorporating the isometry constraints within the objective function of the LDML algorithm. The proposed algorithm is compared with the existing techniques on the publicly available labeled faces in the wild, viewpoint-invariant pedestrian recognition, and Toy Cars data sets. The IC-LDML algorithm has outperformed existing techniques for the tasks of face recognition, person identification, and object classification by a significant margin.

Indicators and metrics for the assessment of climate engineering

NASA Astrophysics Data System (ADS)

Oschlies, A.; Held, H.; Keller, D.; Keller, K.; Mengis, N.; Quaas, M.; Rickels, W.; Schmidt, H.

2017-01-01

Selecting appropriate indicators is essential to aggregate the information provided by climate model outputs into a manageable set of relevant metrics on which assessments of climate engineering (CE) can be based. From all the variables potentially available from climate models, indicators need to be selected that are able to inform scientists and society on the development of the Earth system under CE, as well as on possible impacts and side effects of various ways of deploying CE or not. However, the indicators used so far have been largely identical to those used in climate change assessments and do not visibly reflect the fact that indicators for assessing CE (and thus the metrics composed of these indicators) may be different from those used to assess global warming. Until now, there has been little dedicated effort to identifying specific indicators and metrics for assessing CE. We here propose that such an effort should be facilitated by a more decision-oriented approach and an iterative procedure in close interaction between academia, decision makers, and stakeholders. Specifically, synergies and trade-offs between social objectives reflected by individual indicators, as well as decision-relevant uncertainties should be considered in the development of metrics, so that society can take informed decisions about climate policy measures under the impression of the options available, their likely effects and side effects, and the quality of the underlying knowledge base.

Bibliometrics: tracking research impact by selecting the appropriate metrics

PubMed Central

Agarwal, Ashok; Durairajanayagam, Damayanthi; Tatagari, Sindhuja; Esteves, Sandro C; Harlev, Avi; Henkel, Ralf; Roychoudhury, Shubhadeep; Homa, Sheryl; Puchalt, Nicolás Garrido; Ramasamy, Ranjith; Majzoub, Ahmad; Ly, Kim Dao; Tvrda, Eva; Assidi, Mourad; Kesari, Kavindra; Sharma, Reecha; Banihani, Saleem; Ko, Edmund; Abu-Elmagd, Muhammad; Gosalvez, Jaime; Bashiri, Asher

2016-01-01

Traditionally, the success of a researcher is assessed by the number of publications he or she publishes in peer-reviewed, indexed, high impact journals. This essential yardstick, often referred to as the impact of a specific researcher, is assessed through the use of various metrics. While researchers may be acquainted with such matrices, many do not know how to use them to enhance their careers. In addition to these metrics, a number of other factors should be taken into consideration to objectively evaluate a scientist's profile as a researcher and academician. Moreover, each metric has its own limitations that need to be considered when selecting an appropriate metric for evaluation. This paper provides a broad overview of the wide array of metrics currently in use in academia and research. Popular metrics are discussed and defined, including traditional metrics and article-level metrics, some of which are applied to researchers for a greater understanding of a particular concept, including varicocele that is the thematic area of this Special Issue of Asian Journal of Andrology. We recommend the combined use of quantitative and qualitative evaluation using judiciously selected metrics for a more objective assessment of scholarly output and research impact. PMID:26806079

Organ quality metrics are a poor predictor of costs and resource utilization in deceased donor kidney transplantation.

PubMed

Stahl, Christopher C; Wima, Koffi; Hanseman, Dennis J; Hoehn, Richard S; Ertel, Audrey; Midura, Emily F; Hohmann, Samuel F; Paquette, Ian M; Shah, Shimul A; Abbott, Daniel E

2015-12-01

The desire to provide cost-effective care has lead to an investigation of the costs of therapy for end-stage renal disease. Organ quality metrics are one way to attempt to stratify kidney transplants, although the ability of these metrics to predict costs and resource use is undetermined. The Scientific Registry of Transplant Recipients database was linked to the University HealthSystem Consortium Database to identify adult deceased donor kidney transplant recipients from 2009 to 2012. Patients were divided into cohorts by kidney criteria (standard vs expanded) or kidney donor profile index (KDPI) score (<85 vs 85+). Length of stay, 30-day readmission, discharge disposition, and delayed graft function were used as indicators of resource use. Cost was defined as reimbursement based on Medicare cost/charge ratios and included the costs of readmission when applicable. More than 19,500 patients populated the final dataset. Lower-quality kidneys (expanded criteria donor or KDPI 85+) were more likely to be transplanted in older (both P < .001) and diabetic recipients (both P < .001). After multivariable analysis controlling for recipient characteristics, we found that expanded criteria donor transplants were not associated with increased costs compared with standard criteria donor transplants (risk ratio [RR] 0.97, 95% confidence interval [CI] 0.93-1.00, P = .07). KDPI 85+ was associated with slightly lower costs than KDPI <85 transplants (RR 0.95, 95% CI 0.91-0.99, P = .02). When KDPI was considered as a continuous variable, the association was maintained (RR 0.9993, 95% CI 0.999-0.9998, P = .01). Organ quality metrics are less influential predictors of short-term costs than recipient factors. Future studies should focus on recipient characteristics as a way to discern high versus low cost transplantation procedures. Copyright © 2015 Elsevier Inc. All rights reserved.

A Metric and Workflow for Quality Control in the Analysis of Heterogeneity in Phenotypic Profiles and Screens

PubMed Central

Gough, Albert; Shun, Tongying; Taylor, D. Lansing; Schurdak, Mark

2016-01-01

Heterogeneity is well recognized as a common property of cellular systems that impacts biomedical research and the development of therapeutics and diagnostics. Several studies have shown that analysis of heterogeneity: gives insight into mechanisms of action of perturbagens; can be used to predict optimal combination therapies; and to quantify heterogeneity in tumors where heterogeneity is believed to be associated with adaptation and resistance. Cytometry methods including high content screening (HCS), high throughput microscopy, flow cytometry, mass spec imaging and digital pathology capture cell level data for populations of cells. However it is often assumed that the population response is normally distributed and therefore that the average adequately describes the results. A deeper understanding of the results of the measurements and more effective comparison of perturbagen effects requires analysis that takes into account the distribution of the measurements, i.e. the heterogeneity. However, the reproducibility of heterogeneous data collected on different days, and in different plates/slides has not previously been evaluated. Here we show that conventional assay quality metrics alone are not adequate for quality control of the heterogeneity in the data. To address this need, we demonstrate the use of the Kolmogorov-Smirnov statistic as a metric for monitoring the reproducibility of heterogeneity in an SAR screen, describe a workflow for quality control in heterogeneity analysis. One major challenge in high throughput biology is the evaluation and interpretation of heterogeneity in thousands of samples, such as compounds in a cell-based screen. In this study we also demonstrate that three heterogeneity indices previously reported, capture the shapes of the distributions and provide a means to filter and browse big data sets of cellular distributions in order to compare and identify distributions of interest. These metrics and methods are presented as a

Hospital readiness for health information exchange: development of metrics associated with successful collaboration for quality improvement.

PubMed

Korst, Lisa M; Aydin, Carolyn E; Signer, Jordana M K; Fink, Arlene

2011-08-01

The development of readiness metrics for organizational participation in health information exchange is critical for monitoring progress toward, and achievement of, successful inter-organizational collaboration. In preparation for the development of a tool to measure readiness for data-sharing, we tested whether organizational capacities known to be related to readiness were associated with successful participation in an American data-sharing collaborative for quality improvement. Cross-sectional design, using an on-line survey of hospitals in a large, mature data-sharing collaborative organized for benchmarking and improvement in nursing care quality. Factor analysis was used to identify salient constructs, and identified factors were analyzed with respect to "successful" participation. "Success" was defined as the incorporation of comparative performance data into the hospital dashboard. The most important factor in predicting success included survey items measuring the strength of organizational leadership in fostering a culture of quality improvement (QI Leadership): (1) presence of a supportive hospital executive; (2) the extent to which a hospital values data; (3) the presence of leaders' vision for how the collaborative advances the hospital's strategic goals; (4) hospital use of the collaborative data to track quality outcomes; and (5) staff recognition of a strong mandate for collaborative participation (α=0.84, correlation with Success 0.68 [P<0.0001]). The data emphasize the importance of hospital QI Leadership in collaboratives that aim to share data for QI or safety purposes. Such metrics should prove useful in the planning and development of this complex form of inter-organizational collaboration. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The power metric: a new statistically robust enrichment-type metric for virtual screening applications with early recovery capability.

PubMed

Lopes, Julio Cesar Dias; Dos Santos, Fábio Mendes; Martins-José, Andrelly; Augustyns, Koen; De Winter, Hans

2017-01-01

A new metric for the evaluation of model performance in the field of virtual screening and quantitative structure-activity relationship applications is described. This metric has been termed the power metric and is defined as the fraction of the true positive rate divided by the sum of the true positive and false positive rates, for a given cutoff threshold. The performance of this metric is compared with alternative metrics such as the enrichment factor, the relative enrichment factor, the receiver operating curve enrichment factor, the correct classification rate, Matthews correlation coefficient and Cohen's kappa coefficient. The performance of this new metric is found to be quite robust with respect to variations in the applied cutoff threshold and ratio of the number of active compounds to the total number of compounds, and at the same time being sensitive to variations in model quality. It possesses the correct characteristics for its application in early-recognition virtual screening problems.

Application of sigma metrics for the assessment of quality control in clinical chemistry laboratory in Ghana: A pilot study.

PubMed

Afrifa, Justice; Gyekye, Seth A; Owiredu, William K B A; Ephraim, Richard K D; Essien-Baidoo, Samuel; Amoah, Samuel; Simpong, David L; Arthur, Aaron R

2015-01-01

Sigma metrics provide a uniquely defined scale with which we can assess the performance of a laboratory. The objective of this study was to assess the internal quality control (QC) in the clinical chemistry laboratory of the University of Cape Cost Hospital (UCC) using the six sigma metrics application. We used commercial control serum [normal (L1) and pathological (L2)] for validation of quality control. Metabolites (glucose, urea, and creatinine), lipids [triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C)], enzymes [alkaline phosphatase (ALP), alanine aminotransferase (AST)], electrolytes (sodium, potassium, chloride) and total protein were assessed. Between-day imprecision (CVs), inaccuracy (Bias) and sigma values were calculated for each control level. Apart from sodium (2.40%, 3.83%), chloride (2.52% and 2.51%) for both L1 and L2 respectively, and glucose (4.82%), cholesterol (4.86%) for L2, CVs for all other parameters (both L1 and L2) were >5%. Four parameters (HDL-C, urea, creatinine and potassium) achieved sigma levels >1 for both controls. Chloride and sodium achieved sigma levels >1 for L1 but <1 for L2. In contrast, cholesterol, total protein and AST achieved sigma levels <1 for L1 but >1 for L2. Glucose and ALP achieved a sigma level >1 for both control levels whereas TG achieved a sigma level >2 for both control levels. Unsatisfactory sigma levels (<3) where achieved for all parameters using both control levels, this shows instability and low consistency of results. There is the need for detailed assessment of the analytical procedures and the strengthening of the laboratory control systems in order to achieve effective six sigma levels for the laboratory.

Application of sigma metrics for the assessment of quality control in clinical chemistry laboratory in Ghana: A pilot study

PubMed Central

Afrifa, Justice; Gyekye, Seth A.; Owiredu, William K. B. A.; Ephraim, Richard K. D.; Essien-Baidoo, Samuel; Amoah, Samuel; Simpong, David L.; Arthur, Aaron R.

2015-01-01

Background: Sigma metrics provide a uniquely defined scale with which we can assess the performance of a laboratory. The objective of this study was to assess the internal quality control (QC) in the clinical chemistry laboratory of the University of Cape Cost Hospital (UCC) using the six sigma metrics application. Materials and Methods: We used commercial control serum [normal (L1) and pathological (L2)] for validation of quality control. Metabolites (glucose, urea, and creatinine), lipids [triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C)], enzymes [alkaline phosphatase (ALP), alanine aminotransferase (AST)], electrolytes (sodium, potassium, chloride) and total protein were assessed. Between-day imprecision (CVs), inaccuracy (Bias) and sigma values were calculated for each control level. Results: Apart from sodium (2.40%, 3.83%), chloride (2.52% and 2.51%) for both L1 and L2 respectively, and glucose (4.82%), cholesterol (4.86%) for L2, CVs for all other parameters (both L1 and L2) were >5%. Four parameters (HDL-C, urea, creatinine and potassium) achieved sigma levels >1 for both controls. Chloride and sodium achieved sigma levels >1 for L1 but <1 for L2. In contrast, cholesterol, total protein and AST achieved sigma levels <1 for L1 but >1 for L2. Glucose and ALP achieved a sigma level >1 for both control levels whereas TG achieved a sigma level >2 for both control levels. Conclusion: Unsatisfactory sigma levels (<3) where achieved for all parameters using both control levels, this shows instability and low consistency of results. There is the need for detailed assessment of the analytical procedures and the strengthening of the laboratory control systems in order to achieve effective six sigma levels for the laboratory. PMID:25657495

Sustainability Indicators and Metrics

EPA Science Inventory

Sustainability is about preserving human existence. Indicators and metrics are absolutely necessary to provide at least a semi-quantitative assessment of progress towards or away from sustainability. Otherwise, it becomes impossible to objectively assess whether progress is bei...

D Imaging for Museum Artefacts: a Portable Test Object for Heritage and Museum Documentation of Small Objects

NASA Astrophysics Data System (ADS)

Hess, M.; Robson, S.

2012-07-01

3D colour image data generated for the recording of small museum objects and archaeological finds are highly variable in quality and fitness for purpose. Whilst current technology is capable of extremely high quality outputs, there are currently no common standards or applicable guidelines in either the museum or engineering domain suited to scientific evaluation, understanding and tendering for 3D colour digital data. This paper firstly explains the rationale towards and requirements for 3D digital documentation in museums. Secondly it describes the design process, development and use of a new portable test object suited to sensor evaluation and the provision of user acceptance metrics. The test object is specifically designed for museums and heritage institutions and includes known surface and geometric properties which support quantitative and comparative imaging on different systems. The development for a supporting protocol will allow object reference data to be included in the data processing workflow with specific reference to conservation and curation.

Implementation of a Clinical Documentation Improvement Curriculum Improves Quality Metrics and Hospital Charges in an Academic Surgery Department.

PubMed

Reyes, Cynthia; Greenbaum, Alissa; Porto, Catherine; Russell, John C

2017-03-01

Accurate clinical documentation (CD) is necessary for many aspects of modern health care, including excellent communication, quality metrics reporting, and legal documentation. New requirements have mandated adoption of ICD-10-CM coding systems, adding another layer of complexity to CD. A clinical documentation improvement (CDI) and ICD-10 training program was created for health care providers in our academic surgery department. We aimed to assess the impact of our CDI curriculum by comparing quality metrics, coding, and reimbursement before and after implementation of our CDI program. A CDI/ICD-10 training curriculum was instituted in September 2014 for all members of our university surgery department. The curriculum consisted of didactic lectures, 1-on-1 provider training, case reviews, e-learning modules, and CD queries from nurse CDI staff and hospital coders. Outcomes parameters included monthly documentation completion rates, severity of illness (SOI), risk of mortality (ROM), case-mix index (CMI), all-payer refined diagnosis-related groups (APR-DRG), and Surgical Care Improvement Program (SCIP) metrics. Financial gain from responses to CDI queries was determined retrospectively. Surgery department delinquent documentation decreased by 85% after CDI implementation. Compliance with SCIP measures improved from 85% to 97%. Significant increases in surgical SOI, ROM, CMI, and APR-DRG (all p < 0.01) were found after CDI/ICD-10 training implementation. Provider responses to CDI queries resulted in an estimated $4,672,786 increase in charges. Clinical documentation improvement/ICD-10 training in an academic surgery department is an effective method to improve documentation rates, increase the hospital estimated reimbursement based on more accurate CD, and provide better compliance with surgical quality measures. Copyright © 2016 American College of Surgeons. All rights reserved.

No-reference image quality assessment for horizontal-path imaging scenarios

NASA Astrophysics Data System (ADS)

Rios, Carlos; Gladysz, Szymon

2013-05-01

There exist several image-enhancement algorithms and tasks associated with imaging through turbulence that depend on defining the quality of an image. Examples include: "lucky imaging", choosing the width of the inverse filter for image reconstruction, or stopping iterative deconvolution. We collected a number of image quality metrics found in the literature. Particularly interesting are the blind, "no-reference" metrics. We discuss ways of evaluating the usefulness of these metrics, even when a fully objective comparison is impossible because of the lack of a reference image. Metrics are tested on simulated and real data. Field data comes from experiments performed by the NATO SET 165 research group over a 7 km distance in Dayton, Ohio.

Future of the PCI Readmission Metric.

PubMed

Wasfy, Jason H; Yeh, Robert W

2016-03-01

Between 2013 and 2014, the Centers for Medicare and Medicaid Services and the National Cardiovascular Data Registry publically reported risk-adjusted 30-day readmission rates after percutaneous coronary intervention (PCI) as a pilot project. A key strength of this public reporting effort included risk adjustment with clinical rather than administrative data. Furthermore, because readmission after PCI is common, expensive, and preventable, this metric has substantial potential to improve quality and value in American cardiology care. Despite this, concerns about the metric exist. For example, few PCI readmissions are caused by procedural complications, limiting the extent to which improved procedural technique can reduce readmissions. Also, similar to other readmission measures, PCI readmission is associated with socioeconomic status and race. Accordingly, the metric may unfairly penalize hospitals that care for underserved patients. Perhaps in the context of these limitations, Centers for Medicare and Medicaid Services has not yet included PCI readmission among metrics that determine Medicare financial penalties. Nevertheless, provider organizations may still wish to focus on this metric to improve value for cardiology patients. PCI readmission is associated with low-risk chest discomfort and patient anxiety. Therefore, patient education, improved triage mechanisms, and improved care coordination offer opportunities to minimize PCI readmissions. Because PCI readmission is common and costly, reducing PCI readmission offers provider organizations a compelling target to improve the quality of care, and also performance in contracts involve shared financial risk. © 2016 American Heart Association, Inc.

Objective Methodology to Assess Meaningful Research Productivity by Orthopaedic Residency Departments: Validation Against Widely Distributed Ranking Metrics and Published Surrogates.

PubMed

Jones, Louis B; Goel, Sameer; Hung, Leroy Y; Graves, Matthew L; Spitler, Clay A; Russell, George V; Bergin, Patrick F

2018-04-01

The mission of any academic orthopaedic training program can be divided into 3 general areas of focus: clinical care, academic performance, and research. Clinical care is evaluated on clinical volume, patient outcomes, patient satisfaction, and becoming increasingly focused on data-driven quality metrics. Academic performance of a department can be used to motivate individual surgeons, but objective measures are used to define a residency program. Annual in-service examinations serve as a marker of resident knowledge base, and board pass rates are clearly scrutinized. Research productivity, however, has proven harder to objectively quantify. In an effort to improve transparency and better account for conflicts of interest, bias, and self-citation, multiple bibliometric measures have been developed. Rather than using individuals' research productivity as a surrogate for departmental research, we sought to establish an objective methodology to better assess a residency program's ability to conduct meaningful research. In this study, we describe a process to assess the number and quality of publications produced by an orthopaedic residency department. This would allow chairmen and program directors to benchmark their current production and make measurable goals for future research investment. The main goal of the benchmarking system is to create an "h-index" for residency programs. To do this, we needed to create a list of relevant articles in the orthopaedic literature. We used the Journal Citation Reports. This publication lists all orthopaedic journals that are given an impact factor rating every year. When we accessed the Journal Citation Reports database, there were 72 journals included in the orthopaedic literature section. To ensure only relevant, impactful journals were included, we selected journals with an impact factor greater than 0.95 and an Eigenfactor Score greater than 0.00095. After excluding journals not meeting these criteria, we were left with 45

State of the art metrics for aspect oriented programming

NASA Astrophysics Data System (ADS)

Ghareb, Mazen Ismaeel; Allen, Gary

2018-04-01

The quality evaluation of software, e.g., defect measurement, gains significance with higher use of software applications. Metric measurements are considered as the primary indicator of imperfection prediction and software maintenance in various empirical studies of software products. However, there is no agreement on which metrics are compelling quality indicators for novel development approaches such as Aspect Oriented Programming (AOP). AOP intends to enhance programming quality, by providing new and novel constructs for the development of systems, for example, point cuts, advice and inter-type relationships. Hence, it is not evident if quality pointers for AOP can be derived from direct expansions of traditional OO measurements. Then again, investigations of AOP do regularly depend on established coupling measurements. Notwithstanding the late reception of AOP in empirical studies, coupling measurements have been adopted as useful markers of flaw inclination in this context. In this paper we will investigate the state of the art metrics for measurement of Aspect Oriented systems development.

Development of an Objective Space Suit Mobility Performance Metric Using Metabolic Cost and Functional Tasks

NASA Technical Reports Server (NTRS)

McFarland, Shane M.; Norcross, Jason

2016-01-01

Existing methods for evaluating EVA suit performance and mobility have historically concentrated on isolated joint range of motion and torque. However, these techniques do little to evaluate how well a suited crewmember can actually perform during an EVA. An alternative method of characterizing suited mobility through measurement of metabolic cost to the wearer has been evaluated at Johnson Space Center over the past several years. The most recent study involved six test subjects completing multiple trials of various functional tasks in each of three different space suits; the results indicated it was often possible to discern between different suit designs on the basis of metabolic cost alone. However, other variables may have an effect on real-world suited performance; namely, completion time of the task, the gravity field in which the task is completed, etc. While previous results have analyzed completion time, metabolic cost, and metabolic cost normalized to system mass individually, it is desirable to develop a single metric comprising these (and potentially other) performance metrics. This paper outlines the background upon which this single-score metric is determined to be feasible, and initial efforts to develop such a metric. Forward work includes variable coefficient determination and verification of the metric through repeated testing.

Metrication report to the Congress. 1991 activities and 1992 plans

NASA Technical Reports Server (NTRS)

1991-01-01

During 1991, NASA approved a revised metric use policy and developed a NASA Metric Transition Plan. This Plan targets the end of 1995 for completion of NASA's metric initiatives. This Plan also identifies future programs that NASA anticipates will use the metric system of measurement. Field installations began metric transition studies in 1991 and will complete them in 1992. Half of NASA's Space Shuttle payloads for 1991, and almost all such payloads for 1992, have some metric-based elements. In 1992, NASA will begin assessing requirements for space-quality piece parts fabricated to U.S. metric standards, leading to development and qualification of high priority parts.

Workshop summary: 'Integrating air quality and climate mitigation - is there a need for new metrics to support decision making?'

NASA Astrophysics Data System (ADS)

von Schneidemesser, E.; Schmale, J.; Van Aardenne, J.

2013-12-01

Air pollution and climate change are often treated at national and international level as separate problems under different regulatory or thematic frameworks and different policy departments. With air pollution and climate change being strongly linked with regard to their causes, effects and mitigation options, the integration of policies that steer air pollutant and greenhouse gas emission reductions might result in cost-efficient, more effective and thus more sustainable tackling of the two problems. To support informed decision making and to work towards an integrated air quality and climate change mitigation policy requires the identification, quantification and communication of present-day and potential future co-benefits and trade-offs. The identification of co-benefits and trade-offs requires the application of appropriate metrics that are well rooted in science, easy to understand and reflect the needs of policy, industry and the public for informed decision making. For the purpose of this workshop, metrics were loosely defined as a quantified measure of effect or impact used to inform decision-making and to evaluate mitigation measures. The workshop held on October 9 and 10 and co-organized between the European Environment Agency and the Institute for Advanced Sustainability Studies brought together representatives from science, policy, NGOs, and industry to discuss whether current available metrics are 'fit for purpose' or whether there is a need to develop alternative metrics or reassess the way current metrics are used and communicated. Based on the workshop outcome the presentation will (a) summarize the informational needs and current application of metrics by the end-users, who, depending on their field and area of operation might require health, policy, and/or economically relevant parameters at different scales, (b) provide an overview of the state of the science of currently used and newly developed metrics, and the scientific validity of these

Quality Markers in Cardiology. Main Markers to Measure Quality of Results (Outcomes) and Quality Measures Related to Better Results in Clinical Practice (Performance Metrics). INCARDIO (Indicadores de Calidad en Unidades Asistenciales del Área del Corazón): A SEC/SECTCV Consensus Position Paper.

PubMed

López-Sendón, José; González-Juanatey, José Ramón; Pinto, Fausto; Cuenca Castillo, José; Badimón, Lina; Dalmau, Regina; González Torrecilla, Esteban; López-Mínguez, José Ramón; Maceira, Alicia M; Pascual-Figal, Domingo; Pomar Moya-Prats, José Luis; Sionis, Alessandro; Zamorano, José Luis

2015-11-01

Cardiology practice requires complex organization that impacts overall outcomes and may differ substantially among hospitals and communities. The aim of this consensus document is to define quality markers in cardiology, including markers to measure the quality of results (outcomes metrics) and quality measures related to better results in clinical practice (performance metrics). The document is mainly intended for the Spanish health care system and may serve as a basis for similar documents in other countries. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Memory colours and colour quality evaluation of conventional and solid-state lamps.

PubMed

Smet, Kevin A G; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

2010-12-06

A colour quality metric based on memory colours is presented. The basic idea is simple. The colour quality of a test source is evaluated as the degree of similarity between the colour appearance of a set of familiar objects and their memory colours. The closer the match, the better the colour quality. This similarity was quantified using a set of similarity distributions obtained by Smet et al. in a previous study. The metric was validated by calculating the Pearson and Spearman correlation coefficients between the metric predictions and the visual appreciation results obtained in a validation experiment conducted by the authors as well those obtained in two independent studies. The metric was found to correlate well with the visual appreciation of the lighting quality of the sources used in the three experiments. Its performance was also compared with that of the CIE colour rendering index and the NIST colour quality scale. For all three experiments, the metric was found to be significantly better at predicting the correct visual rank order of the light sources (p < 0.1).

Metric Scale Calculation for Visual Mapping Algorithms

NASA Astrophysics Data System (ADS)

Hanel, A.; Mitschke, A.; Boerner, R.; Van Opdenbosch, D.; Hoegner, L.; Brodie, D.; Stilla, U.

2018-05-01

Visual SLAM algorithms allow localizing the camera by mapping its environment by a point cloud based on visual cues. To obtain the camera locations in a metric coordinate system, the metric scale of the point cloud has to be known. This contribution describes a method to calculate the metric scale for a point cloud of an indoor environment, like a parking garage, by fusing multiple individual scale values. The individual scale values are calculated from structures and objects with a-priori known metric extension, which can be identified in the unscaled point cloud. Extensions of building structures, like the driving lane or the room height, are derived from density peaks in the point distribution. The extension of objects, like traffic signs with a known metric size, are derived using projections of their detections in images onto the point cloud. The method is tested with synthetic image sequences of a drive with a front-looking mono camera through a virtual 3D model of a parking garage. It has been shown, that each individual scale value improves either the robustness of the fused scale value or reduces its error. The error of the fused scale is comparable to other recent works.

A multiple objective optimization approach to quality control

NASA Technical Reports Server (NTRS)

Seaman, Christopher Michael

1991-01-01

The use of product quality as the performance criteria for manufacturing system control is explored. The goal in manufacturing, for economic reasons, is to optimize product quality. The problem is that since quality is a rather nebulous product characteristic, there is seldom an analytic function that can be used as a measure. Therefore standard control approaches, such as optimal control, cannot readily be applied. A second problem with optimizing product quality is that it is typically measured along many dimensions: there are many apsects of quality which must be optimized simultaneously. Very often these different aspects are incommensurate and competing. The concept of optimality must now include accepting tradeoffs among the different quality characteristics. These problems are addressed using multiple objective optimization. It is shown that the quality control problem can be defined as a multiple objective optimization problem. A controller structure is defined using this as the basis. Then, an algorithm is presented which can be used by an operator to interactively find the best operating point. Essentially, the algorithm uses process data to provide the operator with two pieces of information: (1) if it is possible to simultaneously improve all quality criteria, then determine what changes to the process input or controller parameters should be made to do this; and (2) if it is not possible to improve all criteria, and the current operating point is not a desirable one, select a criteria in which a tradeoff should be made, and make input changes to improve all other criteria. The process is not operating at an optimal point in any sense if no tradeoff has to be made to move to a new operating point. This algorithm ensures that operating points are optimal in some sense and provides the operator with information about tradeoffs when seeking the best operating point. The multiobjective algorithm was implemented in two different injection molding scenarios

Quality measurement for rhinosinusitis: a review from the Quality Improvement Committee of the American Rhinologic Society.

PubMed

Rudmik, Luke; Mattos, Jose; Schneider, John; Manes, Peter R; Stokken, Janalee K; Lee, Jivianne; Higgins, Thomas S; Schlosser, Rodney J; Reh, Douglas D; Setzen, Michael; Soler, Zachary M

2017-09-01

Measuring quality outcomes is an important prerequisite to improve quality of care. Rhinosinusitis represents a high value target to improve quality of care because it has a high prevalence of disease, large economic burden, and large practice variation. In this study we review the current state of quality measurement for management of both acute (ARS) and chronic rhinosinusitis (CRS). The major national quality metric repositories and clearinghouses were queried. Additional searches included the American Academy of Otolaryngology-Head and Neck Surgery database, PubMed, and Google to attempt to capture any additional quality metrics. Seven quality metrics for ARS and 4 quality metrics for CRS were identified. ARS metrics focused on appropriateness of diagnosis (n = 1), antibiotic prescribing (n = 4), and radiologic imaging (n = 2). CRS quality metrics focused on appropriateness of diagnosis (n = 1), radiologic imaging (n = 1), and measurement of patient quality of life (n = 2). The Physician Quality Reporting System (PQRS) currently tracks 3 ARS quality metrics and 1 CRS quality metric. There are no outcome-based rhinosinusitis quality metrics and no metrics that assess domains of safety, patient-centeredness, and timeliness of care. The current status of quality measurement for rhinosinusitis has focused primarily on the quality domain of efficiency and process measures for ARS. More work is needed to develop, validate, and track outcome-based quality metrics along with CRS-specific metrics. Although there has been excellent work done to improve quality measurement for rhinosinusitis, there remain major gaps and challenges that need to be considered during the development of future metrics. © 2017 ARS-AAOA, LLC.

Empirical Evaluation of Hunk Metrics as Bug Predictors

NASA Astrophysics Data System (ADS)

Ferzund, Javed; Ahsan, Syed Nadeem; Wotawa, Franz

Reducing the number of bugs is a crucial issue during software development and maintenance. Software process and product metrics are good indicators of software complexity. These metrics have been used to build bug predictor models to help developers maintain the quality of software. In this paper we empirically evaluate the use of hunk metrics as predictor of bugs. We present a technique for bug prediction that works at smallest units of code change called hunks. We build bug prediction models using random forests, which is an efficient machine learning classifier. Hunk metrics are used to train the classifier and each hunk metric is evaluated for its bug prediction capabilities. Our classifier can classify individual hunks as buggy or bug-free with 86 % accuracy, 83 % buggy hunk precision and 77% buggy hunk recall. We find that history based and change level hunk metrics are better predictors of bugs than code level hunk metrics.

Objective measurement of complex multimodal and multidimensional display formats: a common metric for predicting format effectiveness

NASA Astrophysics Data System (ADS)

Marshak, William P.; Darkow, David J.; Wesler, Mary M.; Fix, Edward L.

2000-08-01

Computer-based display designers have more sensory modes and more dimensions within sensory modality with which to encode information in a user interface than ever before. This elaboration of information presentation has made measurement of display/format effectiveness and predicting display/format performance extremely difficult. A multivariate method has been devised which isolates critical information, physically measures its signal strength, and compares it with other elements of the display, which act like background noise. This common Metric relates signal-to-noise ratios (SNRs) within each stimulus dimension, then combines SNRs among display modes, dimensions and cognitive factors can predict display format effectiveness. Examples with their Common Metric assessment and validation in performance will be presented along with the derivation of the metric. Implications of the Common Metric in display design and evaluation will be discussed.

Objective Speech Quality Assessment Based on Payload Discrimination of Lost Packets for Cellular Phones in NGN Environment

NASA Astrophysics Data System (ADS)

Uemura, Satoshi; Fukumoto, Norihiro; Yamada, Hideaki; Nakamura, Hajime

A feature of services provided in a Next Generation Network (NGN) is that the end-to-end quality is guaranteed. This is quite a challenging issue, given the considerable fluctuation in network conditions within a Fixed Mobile Convergence (FMC) network. Therefore, a novel approach, whereby a network node and a mobile terminal such as a cellular phone cooperate with each other to control service quality is essential. In order to achieve such cooperation, the mobile terminal needs to become more intelligent so it can estimate the service quality, including the user's perceptual quality, and notify the measurement result to the network node. Subsequently, the network node implements some kind of service control function, such as a resource and admission control function, based on the notification from the mobile terminal. In this paper, the role of the mobile terminal in such collaborative system is focused on. As a part of a QoS/QoE measurement system, we describe an objective speech quality assessment with payload discrimination of lost packets to measure the user's perceptual quality of VoIP. The proposed assessment is so simple that it can be implemented on a cellular phone. We therefore did this as part of the QoS/QoE measurement system. By using the implemented system, we can measure the user's perceptual quality of VoIP as well as the network QoS metrics, in terms of criteria such as packet loss rate, jitter and burstiness in real time.

Landscape pattern metrics and regional assessment

USGS Publications Warehouse

O'Neill, R. V.; Riitters, K.H.; Wickham, J.D.; Jones, K.B.

1999-01-01

The combination of remote imagery data, geographic information systems software, and landscape ecology theory provides a unique basis for monitoring and assessing large-scale ecological systems. The unique feature of the work has been the need to develop and interpret quantitative measures of spatial pattern-the landscape indices. This article reviews what is known about the statistical properties of these pattern metrics and suggests some additional metrics based on island biogeography, percolation theory, hierarchy theory, and economic geography. Assessment applications of this approach have required interpreting the pattern metrics in terms of specific environmental endpoints, such as wildlife and water quality, and research into how to represent synergystic effects of many overlapping sources of stress.

Multi-metric calibration of hydrological model to capture overall flow regimes

NASA Astrophysics Data System (ADS)

Zhang, Yongyong; Shao, Quanxi; Zhang, Shifeng; Zhai, Xiaoyan; She, Dunxian

2016-08-01

Flow regimes (e.g., magnitude, frequency, variation, duration, timing and rating of change) play a critical role in water supply and flood control, environmental processes, as well as biodiversity and life history patterns in the aquatic ecosystem. The traditional flow magnitude-oriented calibration of hydrological model was usually inadequate to well capture all the characteristics of observed flow regimes. In this study, we simulated multiple flow regime metrics simultaneously by coupling a distributed hydrological model with an equally weighted multi-objective optimization algorithm. Two headwater watersheds in the arid Hexi Corridor were selected for the case study. Sixteen metrics were selected as optimization objectives, which could represent the major characteristics of flow regimes. Model performance was compared with that of the single objective calibration. Results showed that most metrics were better simulated by the multi-objective approach than those of the single objective calibration, especially the low and high flow magnitudes, frequency and variation, duration, maximum flow timing and rating. However, the model performance of middle flow magnitude was not significantly improved because this metric was usually well captured by single objective calibration. The timing of minimum flow was poorly predicted by both the multi-metric and single calibrations due to the uncertainties in model structure and input data. The sensitive parameter values of the hydrological model changed remarkably and the simulated hydrological processes by the multi-metric calibration became more reliable, because more flow characteristics were considered. The study is expected to provide more detailed flow information by hydrological simulation for the integrated water resources management, and to improve the simulation performances of overall flow regimes.

Productivity in Pediatric Palliative Care: Measuring and Monitoring an Elusive Metric.

PubMed

Kaye, Erica C; Abramson, Zachary R; Snaman, Jennifer M; Friebert, Sarah E; Baker, Justin N

2017-05-01

Workforce productivity is poorly defined in health care. Particularly in the field of pediatric palliative care (PPC), the absence of consensus metrics impedes aggregation and analysis of data to track workforce efficiency and effectiveness. Lack of uniformly measured data also compromises the development of innovative strategies to improve productivity and hinders investigation of the link between productivity and quality of care, which are interrelated but not interchangeable. To review the literature regarding the definition and measurement of productivity in PPC; to identify barriers to productivity within traditional PPC models; and to recommend novel metrics to study productivity as a component of quality care in PPC. PubMed ® and Cochrane Database of Systematic Reviews searches for scholarly literature were performed using key words (pediatric palliative care, palliative care, team, workforce, workflow, productivity, algorithm, quality care, quality improvement, quality metric, inpatient, hospital, consultation, model) for articles published between 2000 and 2016. Organizational searches of Center to Advance Palliative Care, National Hospice and Palliative Care Organization, National Association for Home Care & Hospice, American Academy of Hospice and Palliative Medicine, Hospice and Palliative Nurses Association, National Quality Forum, and National Consensus Project for Quality Palliative Care were also performed. Additional semistructured interviews were conducted with directors from seven prominent PPC programs across the U.S. to review standard operating procedures for PPC team workflow and productivity. Little consensus exists in the PPC field regarding optimal ways to define, measure, and analyze provider and program productivity. Barriers to accurate monitoring of productivity include difficulties with identification, measurement, and interpretation of metrics applicable to an interdisciplinary care paradigm. In the context of inefficiencies

Objective speech quality evaluation of real-time speech coders

NASA Astrophysics Data System (ADS)

Viswanathan, V. R.; Russell, W. H.; Huggins, A. W. F.

1984-02-01

This report describes the work performed in two areas: subjective testing of a real-time 16 kbit/s adaptive predictive coder (APC) and objective speech quality evaluation of real-time coders. The speech intelligibility of the APC coder was tested using the Diagnostic Rhyme Test (DRT), and the speech quality was tested using the Diagnostic Acceptability Measure (DAM) test, under eight operating conditions involving channel error, acoustic background noise, and tandem link with two other coders. The test results showed that the DRT and DAM scores of the APC coder equalled or exceeded the corresponding test scores fo the 32 kbit/s CVSD coder. In the area of objective speech quality evaluation, the report describes the development, testing, and validation of a procedure for automatically computing several objective speech quality measures, given only the tape-recordings of the input speech and the corresponding output speech of a real-time speech coder.

Brief educational interventions to improve performance on novel quality metrics in ambulatory settings in Kenya: A multi-site pre-post effectiveness trial.

PubMed

Korom, Robert Ryan; Onguka, Stephanie; Halestrap, Peter; McAlhaney, Maureen; Adam, Mary

2017-01-01

The quality of primary care delivered in resource-limited settings is low. While some progress has been made using educational interventions, it is not yet clear how to sustainably improve care for common acute illnesses in the outpatient setting. Management of urinary tract infection is particularly important in resource-limited settings, where it is commonly diagnosed and associated with high levels of antimicrobial resistance. We describe an educational programme targeting non-physician health care providers and its effects on various clinical quality metrics for urinary tract infection. We used a series of educational interventions including 1) formal introduction of a clinical practice guideline, 2) peer-to-peer chart review, and 3) peer-reviewed literature describing local antimicrobial resistance patterns. Interventions were conducted for clinical officers (N = 24) at two outpatient centers near Nairobi, Kenya over a one-year period. The medical records of 474 patients with urinary tract infections were scored on five clinical quality metrics, with the primary outcome being the proportion of cases in which the guideline-recommended antibiotic was prescribed. The results at baseline and following each intervention were compared using chi-squared tests and unpaired two-tailed T-tests for significance. Logistic regression analysis was used to assess for possible confounders. Clinician adherence to the guideline-recommended antibiotic improved significantly during the study period, from 19% at baseline to 68% following all interventions (Χ2 = 150.7, p < 0.001). The secondary outcome of composite quality score also improved significantly from an average of 2.16 to 3.00 on a five-point scale (t = 6.58, p < 0.001). Interventions had different effects at different clinical sites; the primary outcome of appropriate antibiotic prescription was met 83% of the time at Penda Health, and 50% of the time at AICKH, possibly reflecting differences in onboarding and

Evaluating hydrological model performance using information theory-based metrics

USDA-ARS?s Scientific Manuscript database

The accuracy-based model performance metrics not necessarily reflect the qualitative correspondence between simulated and measured streamflow time series. The objective of this work was to use the information theory-based metrics to see whether they can be used as complementary tool for hydrologic m...

DOE JGI Quality Metrics; Approaches to Scaling and Improving Metagenome Assembly (Metagenomics Informatics Challenges Workshop: 10K Genomes at a Time)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Copeland, Alex; Brown, C. Titus

2011-10-13

DOE JGI's Alex Copeland on "DOE JGI Quality Metrics" and Michigan State University's C. Titus Brown on "Approaches to Scaling and Improving Metagenome Assembly" at the Metagenomics Informatics Challenges Workshop held at the DOE JGI on October 12-13, 2011.

DOE JGI Quality Metrics; Approaches to Scaling and Improving Metagenome Assembly (Metagenomics Informatics Challenges Workshop: 10K Genomes at a Time)

ScienceCinema

Copeland, Alex; Brown, C. Titus

2018-04-27

DOE JGI's Alex Copeland on "DOE JGI Quality Metrics" and Michigan State University's C. Titus Brown on "Approaches to Scaling and Improving Metagenome Assembly" at the Metagenomics Informatics Challenges Workshop held at the DOE JGI on October 12-13, 2011.

Can segmentation evaluation metric be used as an indicator of land cover classification accuracy?

NASA Astrophysics Data System (ADS)

Švab Lenarčič, Andreja; Đurić, Nataša; Čotar, Klemen; Ritlop, Klemen; Oštir, Krištof

2016-10-01

It is a broadly established belief that the segmentation result significantly affects subsequent image classification accuracy. However, the actual correlation between the two has never been evaluated. Such an evaluation would be of considerable importance for any attempts to automate the object-based classification process, as it would reduce the amount of user intervention required to fine-tune the segmentation parameters. We conducted an assessment of segmentation and classification by analyzing 100 different segmentation parameter combinations, 3 classifiers, 5 land cover classes, 20 segmentation evaluation metrics, and 7 classification accuracy measures. The reliability definition of segmentation evaluation metrics as indicators of land cover classification accuracy was based on the linear correlation between the two. All unsupervised metrics that are not based on number of segments have a very strong correlation with all classification measures and are therefore reliable as indicators of land cover classification accuracy. On the other hand, correlation at supervised metrics is dependent on so many factors that it cannot be trusted as a reliable classification quality indicator. Algorithms for land cover classification studied in this paper are widely used; therefore, presented results are applicable to a wider area.

An approach for quantitative image quality analysis for CT

NASA Astrophysics Data System (ADS)

Rahimi, Amir; Cochran, Joe; Mooney, Doug; Regensburger, Joe

2016-03-01

An objective and standardized approach to assess image quality of Compute Tomography (CT) systems is required in a wide variety of imaging processes to identify CT systems appropriate for a given application. We present an overview of the framework we have developed to help standardize and to objectively assess CT image quality for different models of CT scanners used for security applications. Within this framework, we have developed methods to quantitatively measure metrics that should correlate with feature identification, detection accuracy and precision, and image registration capabilities of CT machines and to identify strengths and weaknesses in different CT imaging technologies in transportation security. To that end we have designed, developed and constructed phantoms that allow for systematic and repeatable measurements of roughly 88 image quality metrics, representing modulation transfer function, noise equivalent quanta, noise power spectra, slice sensitivity profiles, streak artifacts, CT number uniformity, CT number consistency, object length accuracy, CT number path length consistency, and object registration. Furthermore, we have developed a sophisticated MATLAB based image analysis tool kit to analyze CT generated images of phantoms and report these metrics in a format that is standardized across the considered models of CT scanners, allowing for comparative image quality analysis within a CT model or between different CT models. In addition, we have developed a modified sparse principal component analysis (SPCA) method to generate a modified set of PCA components as compared to the standard principal component analysis (PCA) with sparse loadings in conjunction with Hotelling T2 statistical analysis method to compare, qualify, and detect faults in the tested systems.

Metrics for Assessing the Quality of Groundwater Used for Public Supply, CA, USA: Equivalent-Population and Area.

PubMed

Belitz, Kenneth; Fram, Miranda S; Johnson, Tyler D

2015-07-21

Data from 11,000 public supply wells in 87 study areas were used to assess the quality of nearly all of the groundwater used for public supply in California. Two metrics were developed for quantifying groundwater quality: area with high concentrations (km(2) or proportion) and equivalent-population relying upon groundwater with high concentrations (number of people or proportion). Concentrations are considered high if they are above a human-health benchmark. When expressed as proportions, the metrics are area-weighted and population-weighted detection frequencies. On a statewide-scale, about 20% of the groundwater used for public supply has high concentrations for one or more constituents (23% by area and 18% by equivalent-population). On the basis of both area and equivalent-population, trace elements are more prevalent at high concentrations than either nitrate or organic compounds at the statewide-scale, in eight of nine hydrogeologic provinces, and in about three-quarters of the study areas. At a statewide-scale, nitrate is more prevalent than organic compounds based on area, but not on the basis of equivalent-population. The approach developed for this paper, unlike many studies, recognizes the importance of appropriately weighting information when changing scales, and is broadly applicable to other areas.

Investigation of sparsity metrics for autofocusing in digital holographic microscopy

NASA Astrophysics Data System (ADS)

Fan, Xin; Healy, John J.; Hennelly, Bryan M.

2017-05-01

Digital holographic microscopy (DHM) is an optoelectronic technique that is made up of two parts: (i) the recording of the interference pattern of the diffraction pattern of an object and a known reference wavefield using a digital camera and (ii) the numerical reconstruction of the complex object wavefield using the recorded interferogram and a distance parameter as input. The latter is based on the simulation of optical propagation from the camera plane to a plane at any arbitrary distance from the camera. A key advantage of DHM over conventional microscopy is that both the phase and intensity information of the object can be recovered at any distance, using only one capture, and this facilitates the recording of scenes that may change dynamically and that may otherwise go in and out of focus. Autofocusing using traditional microscopy requires mechanical movement of the translation stage or the microscope objective, and multiple image captures that are then compared using some metric. Autofocusing in DHM is similar, except that the sequence of intensity images, to which the metric is applied, is generated numerically from a single capture. We recently investigated the application of a number of sparsity metrics for DHM autofocusing and in this paper we extend this work to include more such metrics, and apply them over a greater range of biological diatom cells and magnification/numerical apertures. We demonstrate for the first time that these metrics may be grouped together according to matching behavior following high pass filtering.

Toward a metric for patterned injury analysis

NASA Astrophysics Data System (ADS)

Oliver, William R.; Fritsch, Daniel S.

1997-02-01

An intriguing question in the matching of objects with patterned injures in two and three dimensions is that of an appropriate metric for closeness -- is it possible to objectively measure how well an object 'fits' a patterned injury. Many investigators have suggested an energy-based metric, and have used such metrics to analyze craniofacial growth and anatomic variation. A strict dependence on homology is the primary disadvantage of this energy functional for generalized biological structures; many shapes do not have obvious landmarks. Some tentative solutions to the problem of landmark dependency for patterned injury analysis are presented. One intriguing approach comes from recent work in axiomatic vision. This approach has resulted in the development of a multiresolution medial axis for the extraction of shape primitives which can be used as the basis for registration. A scale-based description of this process can be captured in structures called cores, which can describe object shape and position in a highly compact manner. Cores may provide a scale- and shape-based method of determining correspondences necessary for determining the number and position of landmarks for some patterned injuries. Each of the approaches described are generalizable to higher dimensions, and can thus be used to analyze both two- and three- dimensional data. Together, they may represent a reasonable way of measuring shape distance for the purpose of matching objects and wounds, and can be combined with texture measures for a complete description.

Metrics for the NASA Airspace Systems Program

NASA Technical Reports Server (NTRS)

Smith, Jeremy C.; Neitzke, Kurt W.

2009-01-01

This document defines an initial set of metrics for use by the NASA Airspace Systems Program (ASP). ASP consists of the NextGen-Airspace Project and the NextGen-Airportal Project. The work in each project is organized along multiple, discipline-level Research Focus Areas (RFAs). Each RFA is developing future concept elements in support of the Next Generation Air Transportation System (NextGen), as defined by the Joint Planning and Development Office (JPDO). In addition, a single, system-level RFA is responsible for integrating concept elements across RFAs in both projects and for assessing system-wide benefits. The primary purpose of this document is to define a common set of metrics for measuring National Airspace System (NAS) performance before and after the introduction of ASP-developed concepts for NextGen as the system handles increasing traffic. The metrics are directly traceable to NextGen goals and objectives as defined by the JPDO and hence will be used to measure the progress of ASP research toward reaching those goals. The scope of this document is focused on defining a common set of metrics for measuring NAS capacity, efficiency, robustness, and safety at the system-level and at the RFA-level. Use of common metrics will focus ASP research toward achieving system-level performance goals and objectives and enable the discipline-level RFAs to evaluate the impact of their concepts at the system level.

Improving Quality Metric Adherence to Minimally Invasive Breast Biopsy among Surgeons Within a Multihospital Health Care System.

PubMed

Tjoe, Judy A; Greer, Danielle M; Ihde, Sue E; Bares, Diane A; Mikkelson, Wendy M; Weese, James L

2015-09-01

Minimally invasive breast biopsy (MIBB) is the procedure of choice for diagnosing breast lesions indeterminate for malignancy. Multihospital health care systems face challenges achieving systemwide adherence to standardized guidelines among surgeons with varying practice patterns. This study tested whether providing individual feedback about surgeons' use of MIBB to diagnose breast malignancies improved quality metric adherence across a large health care organization. We conducted a prospective matched-pairs study to test differences (or lack of agreement) between periods before and after intervention. All analytical cases of primary breast cancer diagnosed during 2011 (period 1) and from July 2012 to June 2013 (period 2) across a multihospital health care system were reviewed for initial diagnosis by MIBB or open surgical biopsy. Open surgical biopsy was considered appropriate care only if MIBB could not be performed for reasons listed in the American Society of Breast Surgeons' quality measure for preoperative diagnosis of breast cancer. Individual and systemwide results of adherence to the MIBB metric during period 1 were sent to each surgeon in June 2012 and were later compared with period 2 results using McNemar's test of marginal homogeneity for matched binary responses. Forty-six surgeons were evaluated on use of MIBB to diagnose breast cancer. In period 1, metric adherence for 100% of cases was achieved by 37 surgeons, for a systemwide 100% compliance rate of 80.4%. After notification of individual performance, 44 of 46 surgeons used MIBB solely or otherwise appropriate care to diagnose breast cancer, which improved systemwide compliance to 95.7%. Providing individual and systemwide performance results to surgeons can increase self-awareness of practice patterns when diagnosing breast cancer, leading to standardized best-practice care across a large health care organization. Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All

Development of quality metrics for ambulatory pediatric cardiology: Transposition of the great arteries after arterial switch operation.

PubMed

Baker-Smith, Carissa M; Carlson, Karina; Ettedgui, Jose; Tsuda, Takeshi; Jayakumar, K Anitha; Park, Matthew; Tede, Nikola; Uzark, Karen; Fleishman, Craig; Connuck, David; Likes, Maggie; Penny, Daniel J

2018-01-01

To develop quality metrics (QMs) for the ambulatory care of patients with transposition of the great arteries following arterial switch operation (TGA/ASO). Under the auspices of the American College of Cardiology Adult Congenital and Pediatric Cardiology (ACPC) Steering committee, the TGA/ASO team generated candidate QMs related to TGA/ASO ambulatory care. Candidate QMs were submitted to the ACPC Steering Committee and were reviewed for validity and feasibility using individual expert panel member scoring according to the RAND-UCLA methodology. QMs were then made available for review by the entire ACC ACPC during an "open comment period." Final approval of each QM was provided by a vote of the ACC ACPC Council. Patients with TGA who had undergone an ASO were included. Patients with complex transposition were excluded. Twelve candidate QMs were generated. Seven metrics passed the RAND-UCLA process. Four passed the "open comment period" and were ultimately approved by the Council. These included: (1) at least 1 echocardiogram performed during the first year of life reporting on the function, aortic dimension, degree of neoaortic valve insufficiency, the patency of the systemic and pulmonary outflows, the patency of the branch pulmonary arteries and coronary arteries, (2) neurodevelopmental (ND) assessment after ASO; (3) lipid profile by age 11 years; and (4) documentation of a transition of care plan to an adult congenital heart disease (CHD) provider by 18 years of age. Application of the RAND-UCLA methodology and linkage of this methodology to the ACPC approval process led to successful generation of 4 QMs relevant to the care of TGA/ASO pediatric patients in the ambulatory setting. These metrics have now been incorporated into the ACPC Quality Network providing guidance for the care of TGA/ASO patients across 30 CHD centers. © 2017 Wiley Periodicals, Inc.

Visual quality analysis for images degraded by different types of noise

NASA Astrophysics Data System (ADS)

Ponomarenko, Nikolay N.; Lukin, Vladimir V.; Ieremeyev, Oleg I.; Egiazarian, Karen O.; Astola, Jaakko T.

2013-02-01

Modern visual quality metrics take into account different peculiarities of the Human Visual System (HVS). One of them is described by the Weber-Fechner law and deals with the different sensitivity to distortions in image fragments with different local mean values (intensity, brightness). We analyze how this property can be incorporated into a metric PSNRHVS- M. It is shown that some improvement of its performance can be provided. Then, visual quality of color images corrupted by three types of i.i.d. noise (pure additive, pure multiplicative, and signal dependent, Poisson) is analyzed. Experiments with a group of observers are carried out for distorted color images created on the basis of TID2008 database. Several modern HVS-metrics are considered. It is shown that even the best metrics are unable to assess visual quality of distorted images adequately enough. The reasons for this deal with the observer's attention to certain objects in the test images, i.e., with semantic aspects of vision, which are worth taking into account in design of HVS-metrics.

The Health-Related Quality of Life Journey of Gynecologic Oncology Surgical Patients: Implications for the incorporation of patient-reported outcomes into surgical quality metrics

PubMed Central

Doll, Kemi M.; Barber, Emma L.; Bensen, Jeannette T.; Snavely, Anna C.; Gehrig, Paola A.

2016-01-01

Objective To report the changes in patient-reported quality of life for women undergoing gynecologic oncology surgeries. Methods In a prospective cohort study from 10/2013-10/2014, women were enrolled pre-operatively and completed comprehensive interviews at baseline, 1, 3, and 6 months post-operatively. Measures included the disease-specific Functional Assessment of Cancer Therapy-General (FACT-GP), general Patient Reported Outcome Measure Information System (PROMIS) global health and validated measures of anxiety and depression. Bivariate statistics were used to analyze demographic groups and changes in mean scores over time. Results Of 231 patients completing baseline interviews, 185 (80%) completed 1-month, 170 (74%) 3-month, and 174 (75%) 6-month interviews. Minimally invasive (n=115, 63%) and laparotomy (n=60, 32%) procedures were performed. Functional wellbeing (20 -> 17.6, p<.0001) decreased at 1-month, and recovered by 3 and 6 months. Emotional wellbeing increased (16.3 -> 20.1, p<.0001) and anxiety decreased (54.2 -> 49.0, p<.0001) at 1-month, and were stable at 3 and 6 months. Physical wellbeing scales were not sensitive to surgery. These patterns were consistent across procedure type, cancer diagnosis, and adjuvant therapy administration. In an exploratory analysis of the interaction of QOL and quality, patients with increased postoperative healthcare resource use were noted to have higher baseline levels of anxiety. Conclusions For women undergoing gynecologic oncology procedures, temporary declines in functional wellbeing are balanced by improvements in emotional wellbeing and decreased anxiety symptoms after surgery. Not all commonly used QOL surveys are sensitive to changes during the perioperative period and may not be suitable for use in surgical quality metrics. PMID:26957479

Bayesian model evidence as a model evaluation metric

NASA Astrophysics Data System (ADS)

Guthke, Anneli; Höge, Marvin; Nowak, Wolfgang

2017-04-01

When building environmental systems models, we are typically confronted with the questions of how to choose an appropriate model (i.e., which processes to include or neglect) and how to measure its quality. Various metrics have been proposed that shall guide the modeller towards a most robust and realistic representation of the system under study. Criteria for evaluation often address aspects of accuracy (absence of bias) or of precision (absence of unnecessary variance) and need to be combined in a meaningful way in order to address the inherent bias-variance dilemma. We suggest using Bayesian model evidence (BME) as a model evaluation metric that implicitly performs a tradeoff between bias and variance. BME is typically associated with model weights in the context of Bayesian model averaging (BMA). However, it can also be seen as a model evaluation metric in a single-model context or in model comparison. It combines a measure for goodness of fit with a penalty for unjustifiable complexity. Unjustifiable refers to the fact that the appropriate level of model complexity is limited by the amount of information available for calibration. Derived in a Bayesian context, BME naturally accounts for measurement errors in the calibration data as well as for input and parameter uncertainty. BME is therefore perfectly suitable to assess model quality under uncertainty. We will explain in detail and with schematic illustrations what BME measures, i.e. how complexity is defined in the Bayesian setting and how this complexity is balanced with goodness of fit. We will further discuss how BME compares to other model evaluation metrics that address accuracy and precision such as the predictive logscore or other model selection criteria such as the AIC, BIC or KIC. Although computationally more expensive than other metrics or criteria, BME represents an appealing alternative because it provides a global measure of model quality. Even if not applicable to each and every case, we aim

An Improved Suite of Object Oriented Software Measures

NASA Technical Reports Server (NTRS)

Neal, Ralph D.; Weistroffer, H. Roland; Coppins, Richard J.

1997-01-01

In the pursuit of ever increasing productivity, the need to be able to measure specific aspects of software is generally agreed upon. As object oriented programming languages are becoming more and more widely used, metrics specifically designed for object oriented software are required. In recent years there has been an explosion of new, object oriented software metrics proposed in the literature. Unfortunately, many or most of these proposed metrics have not been validated to measure what they claim to measure. In fact, an analysis of many of these metrics shows that they do not satisfy basic properties of measurement theory, and thus their application has to be suspect. In this paper ten improved metrics are proposed and are validated using measurement theory.

Metric-driven harm: an exploration of unintended consequences of performance measurement.

PubMed

Rambur, Betty; Vallett, Carol; Cohen, Judith A; Tarule, Jill Mattuck

2013-11-01

Performance measurement is an increasingly common element of the US health care system. Typically a proxy for high quality outcomes, there has been little systematic investigation of the potential negative unintended consequences of performance metrics, including metric-driven harm. This case study details an incidence of post-surgical metric-driven harm and offers Smith's 1995 work and a patient centered, context sensitive metric model for potential adoption by nurse researchers and clinicians. Implications for further research are discussed. © 2013.

Co-located perinatal psychiatry clinic: impact of adding a psychologist on clinical quality improvement metrics.

PubMed

Pawar, Deepa; Huang, Chiang-Ching; Wichman, Christina

2018-03-02

To describe the impact of adding a psychologist (the intervention) to a co-located perinatal psychiatry clinic (PPC) in terms of effects on clinical quality improvement (QI) metrics. Six-month pre- and postintervention study design with measurement of QI metrics: number of unique patients treated; number of new and established visits; percent no-shows for new and established visits; and mean wait time to new visit. Number of unique patients treated by the psychiatrist increased by 30%, from 90 preintervention to 118 postintervention (p = .06). Total number of visits completed by the psychiatrist increased by 20% from 174 preintervention to 208 postintervention. Mean wait time for new visits for a physician decreased from 20 days preintervention to 14 days postintervention, with a mean difference of 6.4 days (p = .0015). Percentage of no-shows for new visits increased slightly from 23% preintervention to 26% postintervention (p = .72). The percentage of no-shows for established visits decreased significantly from 22% preintervention to 10% postintervention (p < .005). By adding a psychologist to the co-located PPC, we improved quality of perinatal mental health care by improving efficiency, timeliness and patient-centered care. The psychiatrist saw a greater number of unique patients, decreased wait time to new visits and decreased no-show rates for established visits, likely by better matching patient needs with provider services. A psychologist could be a valuable addition to a PPC, given the shortage of psychiatrists in the United States.

Comparing image quality of print-on-demand books and photobooks from web-based vendors

NASA Astrophysics Data System (ADS)

Phillips, Jonathan; Bajorski, Peter; Burns, Peter; Fredericks, Erin; Rosen, Mitchell

2010-01-01

Because of the emergence of e-commerce and developments in print engines designed for economical output of very short runs, there are increased business opportunities and consumer options for print-on-demand books and photobooks. The current state of these printing modes allows for direct uploading of book files via the web, printing on nonoffset printers, and distributing by standard parcel or mail delivery services. The goal of this research is to assess the image quality of print-on-demand books and photobooks produced by various Web-based vendors and to identify correlations between psychophysical results and objective metrics. Six vendors were identified for one-off (single-copy) print-on-demand books, and seven vendors were identified for photobooks. Participants rank ordered overall quality of a subset of individual pages from each book, where the pages included text, photographs, or a combination of the two. Observers also reported overall quality ratings and price estimates for the bound books. Objective metrics of color gamut, color accuracy, accuracy of International Color Consortium profile usage, eye-weighted root mean square L*, and cascaded modulation transfer acutance were obtained and compared to the observer responses. We introduce some new methods for normalizing data as well as for strengthening the statistical significance of the results. Our approach includes the use of latent mixed-effect models. We found statistically significant correlation with overall image quality and some of the spatial metrics, but correlations between psychophysical results and other objective metrics were weak or nonexistent. Strong correlation was found between psychophysical results of overall quality assessment and estimated price associated with quality. The photobook set of vendors reached higher image-quality ratings than the set of print-on-demand vendors. However, the photobook set had higher image-quality variability.

Evaluating Quality Metrics and Cost After Discharge: A Population-based Cohort Study of Value in Health Care Following Elective Major Vascular Surgery.

PubMed

de Mestral, Charles; Salata, Konrad; Hussain, Mohamad A; Kayssi, Ahmed; Al-Omran, Mohammed; Roche-Nagle, Graham

2018-04-18

Early readmission to hospital after surgery is an omnipresent quality metric across surgical fields. We sought to understand the relative importance of hospital readmission among all health services received after hospital discharge. The aim of this study was to characterize 30-day postdischarge cost and risk of an emergency department (ED) visit, readmission, or death after hospitalization for elective major vascular surgery. This is a population-based retrospective cohort study of patients who underwent elective major vascular surgery - carotid endarterectomy, EVAR, open AAA repair, bypass for lower extremity peripheral arterial disease - in Ontario, Canada, between 2004 and 2015. The outcomes of interest included quality metrics - ED visit, readmission, death - and cost to the Ministry of Health, within 30 days of discharge. Costs after discharge included those attributable to hospital readmission, ED visits, rehab, physician billing, outpatient nursing and allied health care, medications, interventions, and tests. Multivariable regression models characterized the association of pre-discharge characteristics with the above-mentioned postdischarge quality metrics and cost. A total of 30,752 patients were identified. Within 30 days of discharge, 2588 (8.4%) patients were readmitted to hospital and 13 patients died (0.04%). Another 4145 (13.5%) patients visited an ED without requiring admission. Across all patients, over half of 30-day postdischarge costs were attributable to outpatient care. Patients at an increased risk of an ED visit, readmission, or death within 30 days of discharge differed from those patients with relatively higher 30-day costs. Events occurring outside the hospital setting should be integral to the evaluation of quality of care and cost after hospitalization for major vascular surgery.

The role of metrics and measurements in a software intensive total quality management environment

NASA Technical Reports Server (NTRS)

Daniels, Charles B.

1992-01-01

Paramax Space Systems began its mission as a member of the Rockwell Space Operations Company (RSOC) team which was the successful bidder on a massive operations consolidation contract for the Mission Operations Directorate (MOD) at JSC. The contract awarded to the team was the Space Transportation System Operations Contract (STSOC). Our initial challenge was to accept responsibility for a very large, highly complex and fragmented collection of software from eleven different contractors and transform it into a coherent, operational baseline. Concurrently, we had to integrate a diverse group of people from eleven different companies into a single, cohesive team. Paramax executives recognized the absolute necessity to develop a business culture based on the concept of employee involvement to execute and improve the complex process of our new environment. Our executives clearly understood that management needed to set the example and lead the way to quality improvement. The total quality management policy and the metrics used in this endeavor are presented.

Metric freeness and projectivity for classical and quantum normed modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helemskii, A Ya

2013-07-31

In functional analysis, there are several diverse approaches to the notion of projective module. We show that a certain general categorical scheme contains all basic versions as special cases. In this scheme, the notion of free object comes to the foreground, and, in the best categories, projective objects are precisely retracts of free ones. We are especially interested in the so-called metric version of projectivity and characterize the metrically free classical and quantum (= operator) normed modules. Informally speaking, so-called extremal projectivity, which was known earlier, is interpreted as a kind of 'asymptotical metric projectivity'. In addition, we answer themore » following specific question in the geometry of normed spaces: what is the structure of metrically projective modules in the simplest case of normed spaces? We prove that metrically projective normed spaces are precisely the subspaces of l{sub 1}(M) (where M is a set) that are denoted by l{sub 1}{sup 0}(M) and consist of finitely supported functions. Thus, in this case, projectivity coincides with freeness. Bibliography: 28 titles.« less

A proposed metric for assessing the measurement quality of individual microarrays

PubMed Central

Kim, Kyoungmi; Page, Grier P; Beasley, T Mark; Barnes, Stephen; Scheirer, Katherine E; Allison, David B

2006-01-01

Background High-density microarray technology is increasingly applied to study gene expression levels on a large scale. Microarray experiments rely on several critical steps that may introduce error and uncertainty in analyses. These steps include mRNA sample extraction, amplification and labeling, hybridization, and scanning. In some cases this may be manifested as systematic spatial variation on the surface of microarray in which expression measurements within an individual array may vary as a function of geographic position on the array surface. Results We hypothesized that an index of the degree of spatiality of gene expression measurements associated with their physical geographic locations on an array could indicate the summary of the physical reliability of the microarray. We introduced a novel way to formulate this index using a statistical analysis tool. Our approach regressed gene expression intensity measurements on a polynomial response surface of the microarray's Cartesian coordinates. We demonstrated this method using a fixed model and presented results from real and simulated datasets. Conclusion We demonstrated the potential of such a quantitative metric for assessing the reliability of individual arrays. Moreover, we showed that this procedure can be incorporated into laboratory practice as a means to set quality control specifications and as a tool to determine whether an array has sufficient quality to be retained in terms of spatial correlation of gene expression measurements. PMID:16430768

App Usage Factor: A Simple Metric to Compare the Population Impact of Mobile Medical Apps.

PubMed

Lewis, Thomas Lorchan; Wyatt, Jeremy C

2015-08-19

One factor when assessing the quality of mobile apps is quantifying the impact of a given app on a population. There is currently no metric which can be used to compare the population impact of a mobile app across different health care disciplines. The objective of this study is to create a novel metric to characterize the impact of a mobile app on a population. We developed the simple novel metric, app usage factor (AUF), defined as the logarithm of the product of the number of active users of a mobile app with the median number of daily uses of the app. The behavior of this metric was modeled using simulated modeling in Python, a general-purpose programming language. Three simulations were conducted to explore the temporal and numerical stability of our metric and a simulated app ecosystem model using a simulated dataset of 20,000 apps. Simulations confirmed the metric was stable between predicted usage limits and remained stable at extremes of these limits. Analysis of a simulated dataset of 20,000 apps calculated an average value for the app usage factor of 4.90 (SD 0.78). A temporal simulation showed that the metric remained stable over time and suitable limits for its use were identified. A key component when assessing app risk and potential harm is understanding the potential population impact of each mobile app. Our metric has many potential uses for a wide range of stakeholders in the app ecosystem, including users, regulators, developers, and health care professionals. Furthermore, this metric forms part of the overall estimate of risk and potential for harm or benefit posed by a mobile medical app. We identify the merits and limitations of this metric, as well as potential avenues for future validation and research.

Metric analysis and data validation across FORTRAN projects

NASA Technical Reports Server (NTRS)

Basili, Victor R.; Selby, Richard W., Jr.; Phillips, Tsai-Yun

1983-01-01

The desire to predict the effort in developing or explaining the quality of software has led to the proposal of several metrics. As a step toward validating these metrics, the Software Engineering Laboratory (SEL) has analyzed the software science metrics, cyclomatic complexity, and various standard program measures for their relation to effort (including design through acceptance testing), development errors (both discrete and weighted according to the amount of time to locate and fix), and one another. The data investigated are collected from a project FORTRAN environment and examined across several projects at once, within individual projects and by reporting accuracy checks demonstrating the need to validate a database. When the data comes from individual programmers or certain validated projects, the metrics' correlations with actual effort seem to be strongest. For modules developed entirely by individual programmers, the validity ratios induce a statistically significant ordering of several of the metrics' correlations. When comparing the strongest correlations, neither software science's E metric cyclomatic complexity not source lines of code appears to relate convincingly better with effort than the others.

Quantitative comparison using Generalized Relative Object Detectability (G-ROD) metrics of an amorphous selenium detector with high resolution Microangiographic Fluoroscopes (MAF) and standard flat panel detectors (FPD).

PubMed

Russ, M; Shankar, A; Jain, A; Setlur Nagesh, S V; Ionita, C N; Scott, C; Karim, K S; Bednarek, D R; Rudin, S

2016-02-27

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25 μ m pixel pitch, and 1000 μ m thick a-Se layer operating at 10V/ μ m bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-prewhitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal-spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide breakthrough abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices.

Using Geometry-Based Metrics as Part of Fitness-for-Purpose Evaluations of 3D City Models

NASA Astrophysics Data System (ADS)

Wong, K.; Ellul, C.

2016-10-01

Three-dimensional geospatial information is being increasingly used in a range of tasks beyond visualisation. 3D datasets, however, are often being produced without exact specifications and at mixed levels of geometric complexity. This leads to variations within the models' geometric and semantic complexity as well as the degree of deviation from the corresponding real world objects. Existing descriptors and measures of 3D data such as CityGML's level of detail are perhaps only partially sufficient in communicating data quality and fitness-for-purpose. This study investigates whether alternative, automated, geometry-based metrics describing the variation of complexity within 3D datasets could provide additional relevant information as part of a process of fitness-for-purpose evaluation. The metrics include: mean vertex/edge/face counts per building; vertex/face ratio; minimum 2D footprint area and; minimum feature length. Each metric was tested on six 3D city models from international locations. The results show that geometry-based metrics can provide additional information on 3D city models as part of fitness-for-purpose evaluations. The metrics, while they cannot be used in isolation, may provide a complement to enhance existing data descriptors if backed up with local knowledge, where possible.

Building structural similarity database for metric learning

NASA Astrophysics Data System (ADS)

Jin, Guoxin; Pappas, Thrasyvoulos N.

2015-03-01

We propose a new approach for constructing databases for training and testing similarity metrics for structurally lossless image compression. Our focus is on structural texture similarity (STSIM) metrics and the matched-texture compression (MTC) approach. We first discuss the metric requirements for structurally lossless compression, which differ from those of other applications such as image retrieval, classification, and understanding. We identify "interchangeability" as the key requirement for metric performance, and partition the domain of "identical" textures into three regions, of "highest," "high," and "good" similarity. We design two subjective tests for data collection, the first relies on ViSiProG to build a database of "identical" clusters, and the second builds a database of image pairs with the "highest," "high," "good," and "bad" similarity labels. The data for the subjective tests is generated during the MTC encoding process, and consist of pairs of candidate and target image blocks. The context of the surrounding image is critical for training the metrics to detect lighting discontinuities, spatial misalignments, and other border artifacts that have a noticeable effect on perceptual quality. The identical texture clusters are then used for training and testing two STSIM metrics. The labelled image pair database will be used in future research.

Can Tweets Predict Citations? Metrics of Social Impact Based on Twitter and Correlation with Traditional Metrics of Scientific Impact

PubMed Central

2011-01-01

Background Citations in peer-reviewed articles and the impact factor are generally accepted measures of scientific impact. Web 2.0 tools such as Twitter, blogs or social bookmarking tools provide the possibility to construct innovative article-level or journal-level metrics to gauge impact and influence. However, the relationship of the these new metrics to traditional metrics such as citations is not known. Objective (1) To explore the feasibility of measuring social impact of and public attention to scholarly articles by analyzing buzz in social media, (2) to explore the dynamics, content, and timing of tweets relative to the publication of a scholarly article, and (3) to explore whether these metrics are sensitive and specific enough to predict highly cited articles. Methods Between July 2008 and November 2011, all tweets containing links to articles in the Journal of Medical Internet Research (JMIR) were mined. For a subset of 1573 tweets about 55 articles published between issues 3/2009 and 2/2010, different metrics of social media impact were calculated and compared against subsequent citation data from Scopus and Google Scholar 17 to 29 months later. A heuristic to predict the top-cited articles in each issue through tweet metrics was validated. Results A total of 4208 tweets cited 286 distinct JMIR articles. The distribution of tweets over the first 30 days after article publication followed a power law (Zipf, Bradford, or Pareto distribution), with most tweets sent on the day when an article was published (1458/3318, 43.94% of all tweets in a 60-day period) or on the following day (528/3318, 15.9%), followed by a rapid decay. The Pearson correlations between tweetations and citations were moderate and statistically significant, with correlation coefficients ranging from .42 to .72 for the log-transformed Google Scholar citations, but were less clear for Scopus citations and rank correlations. A linear multivariate model with time and tweets as significant

CUQI: cardiac ultrasound video quality index

PubMed Central

Razaak, Manzoor; Martini, Maria G.

2016-01-01

Abstract. Medical images and videos are now increasingly part of modern telecommunication applications, including telemedicinal applications, favored by advancements in video compression and communication technologies. Medical video quality evaluation is essential for modern applications since compression and transmission processes often compromise the video quality. Several state-of-the-art video quality metrics used for quality evaluation assess the perceptual quality of the video. For a medical video, assessing quality in terms of “diagnostic” value rather than “perceptual” quality is more important. We present a diagnostic-quality–oriented video quality metric for quality evaluation of cardiac ultrasound videos. Cardiac ultrasound videos are characterized by rapid repetitive cardiac motions and distinct structural information characteristics that are explored by the proposed metric. Cardiac ultrasound video quality index, the proposed metric, is a full reference metric and uses the motion and edge information of the cardiac ultrasound video to evaluate the video quality. The metric was evaluated for its performance in approximating the quality of cardiac ultrasound videos by testing its correlation with the subjective scores of medical experts. The results of our tests showed that the metric has high correlation with medical expert opinions and in several cases outperforms the state-of-the-art video quality metrics considered in our tests. PMID:27014715

Algal bioassessment metrics for wadeable streams and rivers of Maine, USA

USGS Publications Warehouse

Danielson, Thomas J.; Loftin, Cynthia S.; Tsomides, Leonidas; DiFranco, Jeanne L.; Connors, Beth

2011-01-01

Many state water-quality agencies use biological assessment methods based on lotic fish and macroinvertebrate communities, but relatively few states have incorporated algal multimetric indices into monitoring programs. Algae are good indicators for monitoring water quality because they are sensitive to many environmental stressors. We evaluated benthic algal community attributes along a landuse gradient affecting wadeable streams and rivers in Maine, USA, to identify potential bioassessment metrics. We collected epilithic algal samples from 193 locations across the state. We computed weighted-average optima for common taxa for total P, total N, specific conductance, % impervious cover, and % developed watershed, which included all land use that is no longer forest or wetland. We assigned Maine stream tolerance values and categories (sensitive, intermediate, tolerant) to taxa based on their optima and responses to watershed disturbance. We evaluated performance of algal community metrics used in multimetric indices from other regions and novel metrics based on Maine data. Metrics specific to Maine data, such as the relative richness of species characterized as being sensitive in Maine, were more correlated with % developed watershed than most metrics used in other regions. Few community-structure attributes (e.g., species richness) were useful metrics in Maine. Performance of algal bioassessment models would be improved if metrics were evaluated with attributes of local data before inclusion in multimetric indices or statistical models. ?? 2011 by The North American Benthological Society.

A two-metric proposal to specify the color-rendering properties of light sources for retail lighting

NASA Astrophysics Data System (ADS)

Freyssinier, Jean Paul; Rea, Mark

2010-08-01

Lighting plays an important role in supporting retail operations, from attracting customers, to enabling the evaluation of merchandise, to facilitating the completion of the sale. Lighting also contributes to the identity, comfort, and visual quality of a retail store. With the increasing availability and quality of white LEDs, retail lighting specifiers are now considering LED lighting in stores. The color rendering of light sources is a key factor in supporting retail lighting goals and thus influences a light source's acceptance by users and specifiers. However, there is limited information on what consumers' color preferences are, and metrics used to describe the color properties of light sources often are equivocal and fail to predict preference. The color rendering of light sources is described in the industry solely by the color rendering index (CRI), which is only indirectly related to human perception. CRI is intended to characterize the appearance of objects illuminated by the source and is increasingly being challenged because new sources are being developed with increasingly exotic spectral power distributions. This paper discusses how CRI might be augmented to better use it in support of the design objectives for retail merchandising. The proposed guidelines include the use of gamut area index as a complementary metric to CRI for assuring good color rendering.

The data quality analyzer: A quality control program for seismic data

NASA Astrophysics Data System (ADS)

Ringler, A. T.; Hagerty, M. T.; Holland, J.; Gonzales, A.; Gee, L. S.; Edwards, J. D.; Wilson, D.; Baker, A. M.

2015-03-01

The U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL) has several initiatives underway to enhance and track the quality of data produced from ASL seismic stations and to improve communication about data problems to the user community. The Data Quality Analyzer (DQA) is one such development and is designed to characterize seismic station data quality in a quantitative and automated manner. The DQA consists of a metric calculator, a PostgreSQL database, and a Web interface: The metric calculator, SEEDscan, is a Java application that reads and processes miniSEED data and generates metrics based on a configuration file. SEEDscan compares hashes of metadata and data to detect changes in either and performs subsequent recalculations as needed. This ensures that the metric values are up to date and accurate. SEEDscan can be run as a scheduled task or on demand. The PostgreSQL database acts as a central hub where metric values and limited station descriptions are stored at the channel level with one-day granularity. The Web interface dynamically loads station data from the database and allows the user to make requests for time periods of interest, review specific networks and stations, plot metrics as a function of time, and adjust the contribution of various metrics to the overall quality grade of the station. The quantification of data quality is based on the evaluation of various metrics (e.g., timing quality, daily noise levels relative to long-term noise models, and comparisons between broadband data and event synthetics). Users may select which metrics contribute to the assessment and those metrics are aggregated into a "grade" for each station. The DQA is being actively used for station diagnostics and evaluation based on the completed metrics (availability, gap count, timing quality, deviation from a global noise model, deviation from a station noise model, coherence between co-located sensors, and comparison between broadband data and synthetics

JPL's Real-Time Weather Processor project (RWP) metrics and observations at system completion

NASA Technical Reports Server (NTRS)

Loesh, Robert E.; Conover, Robert A.; Malhotra, Shan

1990-01-01

As an integral part of the overall upgraded National Airspace System (NAS), the objective of the Real-Time Weather Processor (RWP) project is to improve the quality of weather information and the timeliness of its dissemination to system users. To accomplish this, an RWP will be installed in each of the Center Weather Service Units (CWSUs), located in 21 of the 23 Air Route Traffic Control Centers (ARTCCs). The RWP System is a prototype system. It is planned that the software will be GFE and that production hardware will be acquired via industry competitive procurement. The ARTCC is a facility established to provide air traffic control service to aircraft operating on Instrument Flight Rules (IFR) flight plans within controlled airspace, principally during the en route phase of the flight. Covered here are requirement metrics, Software Problem Failure Reports (SPFRs), and Ada portability metrics and observations.

It's All Relative: A Validation of Radiation Quality Comparison Metrics

NASA Technical Reports Server (NTRS)

Chappell, Lori J.; Milder, Caitlin M.; Elgart, S. Robin; Semones, Edward J.

2017-01-01

The difference between high-LET and low-LET radiation is quantified by a measure called relative biological effectiveness (RBE). RBE is defined as the ratio of the dose of a reference radiation to that of a test radiation to achieve the same effect level, and thus, is described either as an iso-effector dose-to-dose ratio. A single dose point is not sufficient to calculate an RBE value; therefore, studies with only one dose point usually calculate an effect-to-effect ratio. While not formally used in radiation protection, these iso-dose values may still be informative. Shuryak, et al 2017 investigated the use of an iso-dose metric termed "radiation effects ratio" (RER) and used both RBE and RER to estimate high-LET risks. To apply RBE or RER to risk prediction, the selected metric must be uniquely defined. That is, the calculated value must be consistent within a model given a constant set of constraints and assumptions, regardless of how effects are defined using statistical transformations from raw endpoint data. We first test the RBE and the RER to determine whether they are uniquely defined using transformations applied to raw data. Then, we test whether both metrics can predict heavy ion response data after simulated effect size scaling between human populations or when converting animal to human endpoints.

Knowledge Dissemination of Intimate Partner Violence Intervention Studies Measured Using Alternative Metrics: Results From a Scoping Review.

PubMed

Madden, Kim; Evaniew, Nathan; Scott, Taryn; Domazetoska, Elena; Dosanjh, Pritnek; Li, Chuan Silvia; Thabane, Lehana; Bhandari, Mohit; Sprague, Sheila

2016-07-01

Alternative metrics measure the number of online mentions that an academic paper receives, including mentions in social media and online news outlets. It is important to monitor and measure dispersion of intimate partner violence (IPV) victim intervention research so that we can improve our knowledge translation and exchange (KTE) processes improving utilization of study findings. The objective of this study is to describe the dissemination of published IPV victim intervention studies and to explore which study characteristics are associated with a greater number of alternative metric mentions and conventional citations. As part of a larger scoping review, we conducted a literature search to identify IPV intervention studies. Outcomes included znumber of alternative metric mentions and conventional citations. Fifty-nine studies were included in this study. The median number of alternative metric mentions was six, and the median number of conventional citations was two. Forty-one percent of the studies (24/59) had no alternative metric mentions, and 27% (16/59) had no conventional citations. Longer time since publication was significantly associated with a greater number of mentions and citations, as were systematic reviews and randomized controlled trial designs. The majority of IPV studies receive little to no online attention or citations in academic journals, indicating a need for the field to focus on implementing strong knowledge dissemination plans. The papers receiving the most alternative metric mentions and conventional citations were also the more rigorous study designs, indicating a need to focus on study quality. We recommend using alternative metrics in conjunction with conventional metrics to evaluate the full dissemination of IPV research.

Quantitative comparison using generalized relative object detectability (G-ROD) metrics of an amorphous selenium detector with high resolution microangiographic fluoroscopes (MAF) and standard flat panel detectors (FPD)

NASA Astrophysics Data System (ADS)

Russ, M.; Shankar, A.; Jain, A.; Setlur Nagesh, S. V.; Ionita, C. N.; Scott, C.; Karim, K. S.; Bednarek, D. R.; Rudin, S.

2016-03-01

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25μm pixel pitch, and 1000μm thick a-Se layer operating at 10V/μm bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-pre-whitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal- spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide break- through abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices.

Quantitative comparison using Generalized Relative Object Detectability (G-ROD) metrics of an amorphous selenium detector with high resolution Microangiographic Fluoroscopes (MAF) and standard flat panel detectors (FPD)

PubMed Central

Russ, M.; Shankar, A.; Jain, A.; Setlur Nagesh, S. V.; Ionita, C. N.; Scott, C.; Karim, K. S.; Bednarek, D. R.; Rudin, S.

2017-01-01

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25μm pixel pitch, and 1000μm thick a-Se layer operating at 10V/μm bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-prewhitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal-spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide breakthrough abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices. PMID:28615795

Prototypic Development and Evaluation of a Medium Format Metric Camera

NASA Astrophysics Data System (ADS)

Hastedt, H.; Rofallski, R.; Luhmann, T.; Rosenbauer, R.; Ochsner, D.; Rieke-Zapp, D.

2018-05-01

Engineering applications require high-precision 3D measurement techniques for object sizes that vary between small volumes (2-3 m in each direction) and large volumes (around 20 x 20 x 1-10 m). The requested precision in object space (1σ RMS) is defined to be within 0.1-0.2 mm for large volumes and less than 0.01 mm for small volumes. In particular, focussing large volume applications the availability of a metric camera would have different advantages for several reasons: 1) high-quality optical components and stabilisations allow for a stable interior geometry of the camera itself, 2) a stable geometry leads to a stable interior orientation that enables for an a priori camera calibration, 3) a higher resulting precision can be expected. With this article the development and accuracy evaluation of a new metric camera, the ALPA 12 FPS add|metric will be presented. Its general accuracy potential is tested against calibrated lengths in a small volume test environment based on the German Guideline VDI/VDE 2634.1 (2002). Maximum length measurement errors of less than 0.025 mm are achieved with different scenarios having been tested. The accuracy potential for large volumes is estimated within a feasibility study on the application of photogrammetric measurements for the deformation estimation on a large wooden shipwreck in the German Maritime Museum. An accuracy of 0.2 mm-0.4 mm is reached for a length of 28 m (given by a distance from a lasertracker network measurement). All analyses have proven high stabilities of the interior orientation of the camera and indicate the applicability for a priori camera calibration for subsequent 3D measurements.

Sharp metric obstructions for quasi-Einstein metrics

NASA Astrophysics Data System (ADS)

Case, Jeffrey S.

2013-02-01

Using the tractor calculus to study smooth metric measure spaces, we adapt results of Gover and Nurowski to give sharp metric obstructions to the existence of quasi-Einstein metrics on suitably generic manifolds. We do this by introducing an analogue of the Weyl tractor W to the setting of smooth metric measure spaces. The obstructions we obtain can be realized as tensorial invariants which are polynomial in the Riemann curvature tensor and its divergence. By taking suitable limits of their tensorial forms, we then find obstructions to the existence of static potentials, generalizing to higher dimensions a result of Bartnik and Tod, and to the existence of potentials for gradient Ricci solitons.

Evaluating the Good Ontology Design Guideline (GoodOD) with the ontology quality requirements and evaluation method and metrics (OQuaRE).

PubMed

Duque-Ramos, Astrid; Boeker, Martin; Jansen, Ludger; Schulz, Stefan; Iniesta, Miguela; Fernández-Breis, Jesualdo Tomás

2014-01-01

To (1) evaluate the GoodOD guideline for ontology development by applying the OQuaRE evaluation method and metrics to the ontology artefacts that were produced by students in a randomized controlled trial, and (2) informally compare the OQuaRE evaluation method with gold standard and competency questions based evaluation methods, respectively. In the last decades many methods for ontology construction and ontology evaluation have been proposed. However, none of them has become a standard and there is no empirical evidence of comparative evaluation of such methods. This paper brings together GoodOD and OQuaRE. GoodOD is a guideline for developing robust ontologies. It was previously evaluated in a randomized controlled trial employing metrics based on gold standard ontologies and competency questions as outcome parameters. OQuaRE is a method for ontology quality evaluation which adapts the SQuaRE standard for software product quality to ontologies and has been successfully used for evaluating the quality of ontologies. In this paper, we evaluate the effect of training in ontology construction based on the GoodOD guideline within the OQuaRE quality evaluation framework and compare the results with those obtained for the previous studies based on the same data. Our results show a significant effect of the GoodOD training over developed ontologies by topics: (a) a highly significant effect was detected in three topics from the analysis of the ontologies of untrained and trained students; (b) both positive and negative training effects with respect to the gold standard were found for five topics. The GoodOD guideline had a significant effect over the quality of the ontologies developed. Our results show that GoodOD ontologies can be effectively evaluated using OQuaRE and that OQuaRE is able to provide additional useful information about the quality of the GoodOD ontologies.

Metrics for comparing climate impacts of short- and long-lived climate forcing agents

NASA Astrophysics Data System (ADS)

Fuglestvedt, J.; Berntsen, T.

2013-12-01

Human activities emit a wide variety of gases and aerosols, with different characteristics that influence both air quality and climate. The emissions affect climate both directly and indirectly and operate on both short and long timescales. Tools that allow these emissions to be placed on a common scale in terms of climate impact, i.e. metrics, have a number of applications (e.g. agreements and emission trading schemes, when considering potential trade-offs between changes in emissions). The Kyoto Protocol compares greenhouse gas (GHG) emissions using the Global Warming Potential (GWP) over a 100 year time-horizon. The IPCC First Assessment Report states the GWP was presented to illustrate the difficulties in comparing GHGs. There have been many critiques of the GWP and several alternative emission metrics have been proposed, but there has been little focus on understanding the linkages between, and interpretations of, different emission metrics. Furthermore, the capability to compare components with very different lifetimes and temporal behaviour needs consideration. The temperature based metrics (e.g. the Global Temperature change Potential (GTP)) require a model for the temperature response, and additional uncertainty is thus introduced. Short-lived forcers may also give more spatially heterogeneous responses, and the possibilities to capture these spatial variations by using other indicators than global mean RF or temperature change in metrics will be discussed. The ultimate choice of emission metric(s) and time-horizon(s) should, however, depend on the objectives of climate policy. Alternatives to the current 'multi-gas and single-basket' approach will also be explored and discussed (e.g. how a two-target approach may be implemented using a two-basket approach). One example is measures to reduce near-term rate of warming and long-term stabilization which can be implemented through two separate targets and two baskets with separate set of metrics for each

Assessing the quality of restored images in optical long-baseline interferometry

NASA Astrophysics Data System (ADS)

Gomes, Nuno; Garcia, Paulo J. V.; Thiébaut, Éric

2017-03-01

Assessing the quality of aperture synthesis maps is relevant for benchmarking image reconstruction algorithms, for the scientific exploitation of data from optical long-baseline interferometers, and for the design/upgrade of new/existing interferometric imaging facilities. Although metrics have been proposed in these contexts, no systematic study has been conducted on the selection of a robust metric for quality assessment. This article addresses the question: what is the best metric to assess the quality of a reconstructed image? It starts by considering several metrics and selecting a few based on general properties. Then, a variety of image reconstruction cases are considered. The observational scenarios are phase closure and phase referencing at the Very Large Telescope Interferometer (VLTI), for a combination of two, three, four and six telescopes. End-to-end image reconstruction is accomplished with the MIRA software, and several merit functions are put to test. It is found that convolution by an effective point spread function is required for proper image quality assessment. The effective angular resolution of the images is superior to naive expectation based on the maximum frequency sampled by the array. This is due to the prior information used in the aperture synthesis algorithm and to the nature of the objects considered. The ℓ1-norm is the most robust of all considered metrics, because being linear it is less sensitive to image smoothing by high regularization levels. For the cases considered, this metric allows the implementation of automatic quality assessment of reconstructed images, with a performance similar to human selection.

Metric Madness

ERIC Educational Resources Information Center

Kroon, Cindy D.

2007-01-01

Created for a Metric Day activity, Metric Madness is a board game for two to four players. Students review and practice metric vocabulary, measurement, and calculations by playing the game. Playing time is approximately twenty to thirty minutes.

Make It Metric.

ERIC Educational Resources Information Center

Camilli, Thomas

Measurement is perhaps the most frequently used form of mathematics. This book presents activities for learning about the metric system designed for upper intermediate and junior high levels. Discussions include: why metrics, history of metrics, changing to a metric world, teaching tips, and formulas. Activities presented are: metrics all around…

Implicit Contractive Mappings in Modular Metric and Fuzzy Metric Spaces

PubMed Central

Hussain, N.; Salimi, P.

2014-01-01

The notion of modular metric spaces being a natural generalization of classical modulars over linear spaces like Lebesgue, Orlicz, Musielak-Orlicz, Lorentz, Orlicz-Lorentz, and Calderon-Lozanovskii spaces was recently introduced. In this paper we investigate the existence of fixed points of generalized α-admissible modular contractive mappings in modular metric spaces. As applications, we derive some new fixed point theorems in partially ordered modular metric spaces, Suzuki type fixed point theorems in modular metric spaces and new fixed point theorems for integral contractions. In last section, we develop an important relation between fuzzy metric and modular metric and deduce certain new fixed point results in triangular fuzzy metric spaces. Moreover, some examples are provided here to illustrate the usability of the obtained results. PMID:25003157

A comparative study of multi-focus image fusion validation metrics

NASA Astrophysics Data System (ADS)

Giansiracusa, Michael; Lutz, Adam; Messer, Neal; Ezekiel, Soundararajan; Alford, Mark; Blasch, Erik; Bubalo, Adnan; Manno, Michael

2016-05-01

Fusion of visual information from multiple sources is relevant for applications security, transportation, and safety applications. One way that image fusion can be particularly useful is when fusing imagery data from multiple levels of focus. Different focus levels can create different visual qualities for different regions in the imagery, which can provide much more visual information to analysts when fused. Multi-focus image fusion would benefit a user through automation, which requires the evaluation of the fused images to determine whether they have properly fused the focused regions of each image. Many no-reference metrics, such as information theory based, image feature based and structural similarity-based have been developed to accomplish comparisons. However, it is hard to scale an accurate assessment of visual quality which requires the validation of these metrics for different types of applications. In order to do this, human perception based validation methods have been developed, particularly dealing with the use of receiver operating characteristics (ROC) curves and the area under them (AUC). Our study uses these to analyze the effectiveness of no-reference image fusion metrics applied to multi-resolution fusion methods in order to determine which should be used when dealing with multi-focus data. Preliminary results show that the Tsallis, SF, and spatial frequency metrics are consistent with the image quality and peak signal to noise ratio (PSNR).

Calculation and use of an environment's characteristic software metric set

NASA Technical Reports Server (NTRS)

Basili, Victor R.; Selby, Richard W., Jr.

1985-01-01

Since both cost/quality and production environments differ, this study presents an approach for customizing a characteristic set of software metrics to an environment. The approach is applied in the Software Engineering Laboratory (SEL), a NASA Goddard production environment, to 49 candidate process and product metrics of 652 modules from six (51,000 to 112,000 lines) projects. For this particular environment, the method yielded the characteristic metric set (source lines, fault correction effort per executable statement, design effort, code effort, number of I/O parameters, number of versions). The uses examined for a characteristic metric set include forecasting the effort for development, modification, and fault correction of modules based on historical data.

A new normalizing algorithm for BAC CGH arrays with quality control metrics.

PubMed

Miecznikowski, Jeffrey C; Gaile, Daniel P; Liu, Song; Shepherd, Lori; Nowak, Norma

2011-01-01

The main focus in pin-tip (or print-tip) microarray analysis is determining which probes, genes, or oligonucleotides are differentially expressed. Specifically in array comparative genomic hybridization (aCGH) experiments, researchers search for chromosomal imbalances in the genome. To model this data, scientists apply statistical methods to the structure of the experiment and assume that the data consist of the signal plus random noise. In this paper we propose "SmoothArray", a new method to preprocess comparative genomic hybridization (CGH) bacterial artificial chromosome (BAC) arrays and we show the effects on a cancer dataset. As part of our R software package "aCGHplus," this freely available algorithm removes the variation due to the intensity effects, pin/print-tip, the spatial location on the microarray chip, and the relative location from the well plate. removal of this variation improves the downstream analysis and subsequent inferences made on the data. Further, we present measures to evaluate the quality of the dataset according to the arrayer pins, 384-well plates, plate rows, and plate columns. We compare our method against competing methods using several metrics to measure the biological signal. With this novel normalization algorithm and quality control measures, the user can improve their inferences on datasets and pinpoint problems that may arise in their BAC aCGH technology.

Conceptual Soundness, Metric Development, Benchmarking, and Targeting for PATH Subprogram Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mosey. G.; Doris, E.; Coggeshall, C.

The objective of this study is to evaluate the conceptual soundness of the U.S. Department of Housing and Urban Development (HUD) Partnership for Advancing Technology in Housing (PATH) program's revised goals and establish and apply a framework to identify and recommend metrics that are the most useful for measuring PATH's progress. This report provides an evaluative review of PATH's revised goals, outlines a structured method for identifying and selecting metrics, proposes metrics and benchmarks for a sampling of individual PATH programs, and discusses other metrics that potentially could be developed that may add value to the evaluation process. The frameworkmore » and individual program metrics can be used for ongoing management improvement efforts and to inform broader program-level metrics for government reporting requirements.« less

EVALUATION OF METRIC PRECISION FOR A RIPARIAN FOREST SURVEY

EPA Science Inventory

This paper evaluates the performance of a protocol to monitor riparian forests in western Oregon based on the quality of the data obtained from a recent field survey. Precision and accuracy are the criteria used to determine the quality of 19 field metrics. The field survey con...

Hydrologic Model Development and Calibration: Contrasting a Single- and Multi-Objective Approach for Comparing Model Performance

NASA Astrophysics Data System (ADS)

Asadzadeh, M.; Maclean, A.; Tolson, B. A.; Burn, D. H.

2009-05-01

Hydrologic model calibration aims to find a set of parameters that adequately simulates observations of watershed behavior, such as streamflow, or a state variable, such as snow water equivalent (SWE). There are different metrics for evaluating calibration effectiveness that involve quantifying prediction errors, such as the Nash-Sutcliffe (NS) coefficient and bias evaluated for the entire calibration period, on a seasonal basis, for low flows, or for high flows. Many of these metrics are conflicting such that the set of parameters that maximizes the high flow NS differs from the set of parameters that maximizes the low flow NS. Conflicting objectives are very likely when different calibration objectives are based on different fluxes and/or state variables (e.g., NS based on streamflow versus SWE). One of the most popular ways to balance different metrics is to aggregate them based on their importance and find the set of parameters that optimizes a weighted sum of the efficiency metrics. Comparing alternative hydrologic models (e.g., assessing model improvement when a process or more detail is added to the model) based on the aggregated objective might be misleading since it represents one point on the tradeoff of desired error metrics. To derive a more comprehensive model comparison, we solved a bi-objective calibration problem to estimate the tradeoff between two error metrics for each model. Although this approach is computationally more expensive than the aggregation approach, it results in a better understanding of the effectiveness of selected models at each level of every error metric and therefore provides a better rationale for judging relative model quality. The two alternative models used in this study are two MESH hydrologic models (version 1.2) of the Wolf Creek Research basin that differ in their watershed spatial discretization (a single Grouped Response Unit, GRU, versus multiple GRUs). The MESH model, currently under development by Environment

Energy-Based Metrics for Arthroscopic Skills Assessment.

PubMed

Poursartip, Behnaz; LeBel, Marie-Eve; McCracken, Laura C; Escoto, Abelardo; Patel, Rajni V; Naish, Michael D; Trejos, Ana Luisa

2017-08-05

Minimally invasive skills assessment methods are essential in developing efficient surgical simulators and implementing consistent skills evaluation. Although numerous methods have been investigated in the literature, there is still a need to further improve the accuracy of surgical skills assessment. Energy expenditure can be an indication of motor skills proficiency. The goals of this study are to develop objective metrics based on energy expenditure, normalize these metrics, and investigate classifying trainees using these metrics. To this end, different forms of energy consisting of mechanical energy and work were considered and their values were divided by the related value of an ideal performance to develop normalized metrics. These metrics were used as inputs for various machine learning algorithms including support vector machines (SVM) and neural networks (NNs) for classification. The accuracy of the combination of the normalized energy-based metrics with these classifiers was evaluated through a leave-one-subject-out cross-validation. The proposed method was validated using 26 subjects at two experience levels (novices and experts) in three arthroscopic tasks. The results showed that there are statistically significant differences between novices and experts for almost all of the normalized energy-based metrics. The accuracy of classification using SVM and NN methods was between 70% and 95% for the various tasks. The results show that the normalized energy-based metrics and their combination with SVM and NN classifiers are capable of providing accurate classification of trainees. The assessment method proposed in this study can enhance surgical training by providing appropriate feedback to trainees about their level of expertise and can be used in the evaluation of proficiency.

Metrics for measuring net-centric data strategy implementation

NASA Astrophysics Data System (ADS)

Kroculick, Joseph B.

2010-04-01

An enterprise data strategy outlines an organization's vision and objectives for improved collection and use of data. We propose generic metrics and quantifiable measures for each of the DoD Net-Centric Data Strategy (NCDS) data goals. Data strategy metrics can be adapted to the business processes of an enterprise and the needs of stakeholders in leveraging the organization's data assets to provide for more effective decision making. Generic metrics are applied to a specific application where logistics supply and transportation data is integrated across multiple functional groups. A dashboard presents a multidimensional view of the current progress to a state where logistics data shared in a timely and seamless manner among users, applications, and systems.

Objective vocal quality in children using cochlear implants: a multiparameter approach.

PubMed

Baudonck, Nele; D'haeseleer, Evelien; Dhooge, Ingeborg; Van Lierde, Kristiane

2011-11-01

The purpose of this study was to determine the objective vocal quality in 36 prelingually deaf children using cochlear implant (CI) with a mean age of 9 years. An additional purpose was to compare the objective vocal quality of these 36 CI users with 25 age-matched children with prelingual severe hearing loss using conventional hearing aids (HAs) and 25 normal hearing (NH) children. The design for this cross-sectional study was a multigroup posttest-only design. The objective vocal quality was measured by means of the dysphonia severity index (DSI). Moreover, perceptual voice assessment using the GRBASI scale was performed. CI children have a vocal quality by means of the DSI of +1.8, corresponding with a DSI% of 68%, indicating a borderline vocal quality situated 2% above the limit of normality. The voice was perceptually characterized by the presence of a very slight grade of hoarseness, roughness, strained phonation, and higher pitch and intensity levels. No significant objective vocal quality differences were measured between the voices of the CI children, HA users, and NH children. According to the results, one aspect of the vocal approach in children with CI and using HAs must be focused on the improvement of the strained vocal characteristic and the use of a lower pitch and intensity level. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

The Metadata Coverage Index (MCI): A standardized metric for quantifying database metadata richness.

PubMed

Liolios, Konstantinos; Schriml, Lynn; Hirschman, Lynette; Pagani, Ioanna; Nosrat, Bahador; Sterk, Peter; White, Owen; Rocca-Serra, Philippe; Sansone, Susanna-Assunta; Taylor, Chris; Kyrpides, Nikos C; Field, Dawn

2012-07-30

Variability in the extent of the descriptions of data ('metadata') held in public repositories forces users to assess the quality of records individually, which rapidly becomes impractical. The scoring of records on the richness of their description provides a simple, objective proxy measure for quality that enables filtering that supports downstream analysis. Pivotally, such descriptions should spur on improvements. Here, we introduce such a measure - the 'Metadata Coverage Index' (MCI): the percentage of available fields actually filled in a record or description. MCI scores can be calculated across a database, for individual records or for their component parts (e.g., fields of interest). There are many potential uses for this simple metric: for example; to filter, rank or search for records; to assess the metadata availability of an ad hoc collection; to determine the frequency with which fields in a particular record type are filled, especially with respect to standards compliance; to assess the utility of specific tools and resources, and of data capture practice more generally; to prioritize records for further curation; to serve as performance metrics of funded projects; or to quantify the value added by curation. Here we demonstrate the utility of MCI scores using metadata from the Genomes Online Database (GOLD), including records compliant with the 'Minimum Information about a Genome Sequence' (MIGS) standard developed by the Genomic Standards Consortium. We discuss challenges and address the further application of MCI scores; to show improvements in annotation quality over time, to inform the work of standards bodies and repository providers on the usability and popularity of their products, and to assess and credit the work of curators. Such an index provides a step towards putting metadata capture practices and in the future, standards compliance, into a quantitative and objective framework.

Correlates of sleep quality in midlife and beyond: a machine learning analysis.

PubMed

Kaplan, Katherine A; Hardas, Prajesh P; Redline, Susan; Zeitzer, Jamie M

2017-06-01

In older adults, traditional metrics derived from polysomnography (PSG) are not well correlated with subjective sleep quality. Little is known about whether the association between PSG and subjective sleep quality changes with age, or whether quantitative electroencephalography (qEEG) is associated with sleep quality. Therefore, we examined the relationship between subjective sleep quality and objective sleep characteristics (standard PSG and qEEG) across middle to older adulthood. Using cross-sectional analyses of 3173 community-dwelling men and women aged between 39 and 90 participating in the Sleep Heart Health Study, we examined the relationship between a morning rating of the prior night's sleep quality (sleep depth and restfulness) and polysomnographic, and qEEG descriptors of that single night of sleep, along with clinical and demographic measures. Multivariable models were constructed using two machine learning methods, namely lasso penalized regressions and random forests. Little variance was explained across models. Greater objective sleep efficiency, reduced wake after sleep onset, and fewer sleep-to-wake stage transitions were each associated with higher sleep quality; qEEG variables contributed little explanatory power. The oldest adults reported the highest sleep quality even as objective sleep deteriorated such that they would rate their sleep better, given the same level of sleep efficiency. Despite this, there were no major differences in the predictors of subjective sleep across the age span. Standard metrics derived from PSG, including qEEG, contribute little to explaining subjective sleep quality in middle-aged to older adults. The objective correlates of subjective sleep quality do not appear to systematically change with age despite a change in the relationship between subjective sleep quality and objective sleep efficiency. Published by Elsevier B.V.

Essential metrics for assessing sex & gender integration in health research proposals involving human participants.

PubMed

Day, Suzanne; Mason, Robin; Tannenbaum, Cara; Rochon, Paula A

2017-01-01

Integrating sex and gender in health research is essential to produce the best possible evidence to inform health care. Comprehensive integration of sex and gender requires considering these variables from the very beginning of the research process, starting at the proposal stage. To promote excellence in sex and gender integration, we have developed a set of metrics to assess the quality of sex and gender integration in research proposals. These metrics are designed to assist both researchers in developing proposals and reviewers in making funding decisions. We developed this tool through an iterative three-stage method involving 1) review of existing sex and gender integration resources and initial metrics design, 2) expert review and feedback via anonymous online survey (Likert scale and open-ended questions), and 3) analysis of feedback data and collective revision of the metrics. We received feedback on the initial metrics draft from 20 reviewers with expertise in conducting sex- and/or gender-based health research. The majority of reviewers responded positively to questions regarding the utility, clarity and completeness of the metrics, and all reviewers provided responses to open-ended questions about suggestions for improvements. Coding and analysis of responses identified three domains for improvement: clarifying terminology, refining content, and broadening applicability. Based on this analysis we revised the metrics into the Essential Metrics for Assessing Sex and Gender Integration in Health Research Proposals Involving Human Participants, which outlines criteria for excellence within each proposal component and provides illustrative examples to support implementation. By enhancing the quality of sex and gender integration in proposals, the metrics will help to foster comprehensive, meaningful integration of sex and gender throughout each stage of the research process, resulting in better quality evidence to inform health care for all.

Essential metrics for assessing sex & gender integration in health research proposals involving human participants

PubMed Central

Mason, Robin; Tannenbaum, Cara; Rochon, Paula A.

2017-01-01

Integrating sex and gender in health research is essential to produce the best possible evidence to inform health care. Comprehensive integration of sex and gender requires considering these variables from the very beginning of the research process, starting at the proposal stage. To promote excellence in sex and gender integration, we have developed a set of metrics to assess the quality of sex and gender integration in research proposals. These metrics are designed to assist both researchers in developing proposals and reviewers in making funding decisions. We developed this tool through an iterative three-stage method involving 1) review of existing sex and gender integration resources and initial metrics design, 2) expert review and feedback via anonymous online survey (Likert scale and open-ended questions), and 3) analysis of feedback data and collective revision of the metrics. We received feedback on the initial metrics draft from 20 reviewers with expertise in conducting sex- and/or gender-based health research. The majority of reviewers responded positively to questions regarding the utility, clarity and completeness of the metrics, and all reviewers provided responses to open-ended questions about suggestions for improvements. Coding and analysis of responses identified three domains for improvement: clarifying terminology, refining content, and broadening applicability. Based on this analysis we revised the metrics into the Essential Metrics for Assessing Sex and Gender Integration in Health Research Proposals Involving Human Participants, which outlines criteria for excellence within each proposal component and provides illustrative examples to support implementation. By enhancing the quality of sex and gender integration in proposals, the metrics will help to foster comprehensive, meaningful integration of sex and gender throughout each stage of the research process, resulting in better quality evidence to inform health care for all. PMID:28854192

On use of image quality metrics for perceptual blur modeling: image/video compression case

NASA Astrophysics Data System (ADS)

Cha, Jae H.; Olson, Jeffrey T.; Preece, Bradley L.; Espinola, Richard L.; Abbott, A. Lynn

2018-02-01

Linear system theory is employed to make target acquisition performance predictions for electro-optical/infrared imaging systems where the modulation transfer function (MTF) may be imposed from a nonlinear degradation process. Previous research relying on image quality metrics (IQM) methods, which heuristically estimate perceived MTF has supported that an average perceived MTF can be used to model some types of degradation such as image compression. Here, we discuss the validity of the IQM approach by mathematically analyzing the associated heuristics from the perspective of reliability, robustness, and tractability. Experiments with standard images compressed by x.264 encoding suggest that the compression degradation can be estimated by a perceived MTF within boundaries defined by well-behaved curves with marginal error. Our results confirm that the IQM linearizer methodology provides a credible tool for sensor performance modeling.

The role of complexity metrics in a multi-institutional dosimetry audit of VMAT.

PubMed

McGarry, Conor K; Agnew, Christina E; Hussein, Mohammad; Tsang, Yatman; McWilliam, Alan; Hounsell, Alan R; Clark, Catharine H

2016-01-01

To demonstrate the benefit of complexity metrics such as the modulation complexity score (MCS) and monitor units (MUs) in multi-institutional audits of volumetric-modulated arc therapy (VMAT) delivery. 39 VMAT treatment plans were analysed using MCS and MU. A virtual phantom planning exercise was planned and independently measured using the PTW Octavius(®) phantom and seven29(®) 2D array (PTW-Freiburg GmbH, Freiburg, Germany). MCS and MU were compared with the median gamma index pass rates (2%/2 and 3%/3 mm) and plan quality. The treatment planning systems (TPS) were grouped by VMAT modelling being specifically designed for the linear accelerator manufacturer's own treatment delivery system (Type 1) or independent of vendor for VMAT delivery (Type 2). Differences in plan complexity (MCS and MU) between TPS types were compared. For Varian(®) linear accelerators (Varian(®) Medical Systems, Inc., Palo Alto, CA), MCS and MU were significantly correlated with gamma pass rates. Type 2 TPS created poorer quality, more complex plans with significantly higher MUs and MCS than Type 1 TPS. Plan quality was significantly correlated with MU for Type 2 plans. A statistically significant correlation was observed between MU and MCS for all plans (R = -0.84, p < 0.01). MU and MCS have a role in assessing plan complexity in audits along with plan quality metrics. Plan complexity metrics give some indication of plan deliverability but should be analysed with plan quality. Complexity metrics were investigated for a national rotational audit involving 34 institutions and they showed value. The metrics found that more complex plans were created for planning systems which were independent of vendor for VMAT delivery.

Measures and Metrics for Feasibility of Proof-of-Concept Studies With Human Immunodeficiency Virus Rapid Point-of-Care Technologies

PubMed Central

Pant Pai, Nitika; Chiavegatti, Tiago; Vijh, Rohit; Karatzas, Nicolaos; Daher, Jana; Smallwood, Megan; Wong, Tom; Engel, Nora

2017-01-01

Objective Pilot (feasibility) studies form a vast majority of diagnostic studies with point-of-care technologies but often lack use of clear measures/metrics and a consistent framework for reporting and evaluation. To fill this gap, we systematically reviewed data to (a) catalog feasibility measures/metrics and (b) propose a framework. Methods For the period January 2000 to March 2014, 2 reviewers searched 4 databases (MEDLINE, EMBASE, CINAHL, Scopus), retrieved 1441 citations, and abstracted data from 81 studies. We observed 2 major categories of measures, that is, implementation centered and patient centered, and 4 subcategories of measures, that is, feasibility, acceptability, preference, and patient experience. We defined and delineated metrics and measures for a feasibility framework. We documented impact measures for a comparison. Findings We observed heterogeneity in reporting of metrics as well as misclassification and misuse of metrics within measures. Although we observed poorly defined measures and metrics for feasibility, preference, and patient experience, in contrast, acceptability measure was the best defined. For example, within feasibility, metrics such as consent, completion, new infection, linkage rates, and turnaround times were misclassified and reported. Similarly, patient experience was variously reported as test convenience, comfort, pain, and/or satisfaction. In contrast, within impact measures, all the metrics were well documented, thus serving as a good baseline comparator. With our framework, we classified, delineated, and defined quantitative measures and metrics for feasibility. Conclusions Our framework, with its defined measures/metrics, could reduce misclassification and improve the overall quality of reporting for monitoring and evaluation of rapid point-of-care technology strategies and their context-driven optimization. PMID:29333105

Reference-free ground truth metric for metal artifact evaluation in CT images.

PubMed

Kratz, Bärbel; Ens, Svitlana; Müller, Jan; Buzug, Thorsten M

2011-07-01

In computed tomography (CT), metal objects in the region of interest introduce data inconsistencies during acquisition. Reconstructing these data results in an image with star shaped artifacts induced by the metal inconsistencies. To enhance image quality, the influence of the metal objects can be reduced by different metal artifact reduction (MAR) strategies. For an adequate evaluation of new MAR approaches a ground truth reference data set is needed. In technical evaluations, where phantoms can be measured with and without metal inserts, ground truth data can easily be obtained by a second reference data acquisition. Obviously, this is not possible for clinical data. Here, an alternative evaluation method is presented without the need of an additionally acquired reference data set. The proposed metric is based on an inherent ground truth for metal artifacts as well as MAR methods comparison, where no reference information in terms of a second acquisition is needed. The method is based on the forward projection of a reconstructed image, which is compared to the actually measured projection data. The new evaluation technique is performed on phantom and on clinical CT data with and without MAR. The metric results are then compared with methods using a reference data set as well as an expert-based classification. It is shown that the new approach is an adequate quantification technique for artifact strength in reconstructed metal or MAR CT images. The presented method works solely on the original projection data itself, which yields some advantages compared to distance measures in image domain using two data sets. Beside this, no parameters have to be manually chosen. The new metric is a useful evaluation alternative when no reference data are available.

Adaptive distance metric learning for diffusion tensor image segmentation.

PubMed

Kong, Youyong; Wang, Defeng; Shi, Lin; Hui, Steve C N; Chu, Winnie C W

2014-01-01

High quality segmentation of diffusion tensor images (DTI) is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework.

Adaptive Distance Metric Learning for Diffusion Tensor Image Segmentation

PubMed Central

Kong, Youyong; Wang, Defeng; Shi, Lin; Hui, Steve C. N.; Chu, Winnie C. W.

2014-01-01

High quality segmentation of diffusion tensor images (DTI) is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework. PMID:24651858

MO-D-213-06: Quantitative Image Quality Metrics Are for Physicists, Not Radiologists: How to Communicate to Your Radiologists Using Their Language

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szczykutowicz, T; Rubert, N; Ranallo, F

Purpose: A framework for explaining differences in image quality to non-technical audiences in medial imaging is needed. Currently, this task is something that is learned “on the job.” The lack of a formal methodology for communicating optimal acquisition parameters into the clinic effectively mitigates many technological advances. As a community, medical physicists need to be held responsible for not only advancing image science, but also for ensuring its proper use in the clinic. This work outlines a framework that bridges the gap between the results from quantitative image quality metrics like detectability, MTF, and NPS and their effect on specificmore » anatomical structures present in diagnostic imaging tasks. Methods: Specific structures of clinical importance were identified for a body, an extremity, a chest, and a temporal bone protocol. Using these structures, quantitative metrics were used to identify the parameter space that should yield optimal image quality constrained within the confines of clinical logistics and dose considerations. The reading room workflow for presenting the proposed changes for imaging each of these structures is presented. The workflow consists of displaying images for physician review consisting of different combinations of acquisition parameters guided by quantitative metrics. Examples of using detectability index, MTF, NPS, noise and noise non-uniformity are provided. During review, the physician was forced to judge the image quality solely on those features they need for diagnosis, not on the overall “look” of the image. Results: We found that in many cases, use of this framework settled mis-agreements between physicians. Once forced to judge images on the ability to detect specific structures inter reader agreement was obtained. Conclusion: This framework will provide consulting, research/industrial, or in-house physicists with clinically relevant imaging tasks to guide reading room image review. This framework

Operationalizing the Measuring What Matters Spirituality Quality Metric in a Population of Hospitalized, Critically Ill Patients and Their Family Members.

PubMed

Aslakson, Rebecca A; Kweku, Josephine; Kinnison, Malonnie; Singh, Sarabdeep; Crowe, Thomas Y

2017-03-01

Measuring What Matters (MWM) quality indicators support measurement of the percentage of patients who have spiritual discussions, if desired. The objective of this study was to 1) determine the ease of, and barriers to, prospectively collecting MWM spirituality quality measure data and 2) further explore the importance of spirituality in a seriously ill, hospitalized population of critically ill patients and their family members. Electronic medical record (EMR) review and cross-sectional survey of intensive care unit (ICU) patients and their family members from October to December 2015. Participants were in four adult ICUs totaling 68 beds at a single academic, urban, tertiary care center which has ICU-assigned chaplains and an in-house, 24-hour, on-call chaplain. All patients had a "Spiritual Risk Screen" which included two questions identifying patient religion and whether a chaplain visit was desired. Approximately 2/3 of ICU patients were eligible, and there were 144 respondents (50% female; 57% patient and 43% family member), with the majority being Caucasian or African American (68% and 21%, respectively). Common religious identifications were Christian or no faith tradition (76% and 11%, respectively). Approximately half of patients had an EMR chaplain note although it did not document presence of a "spiritual discussion." No study patients received palliative care consultation. A majority (85%) noted that spirituality was "important to them" and that prevalence remained high across respondent age, race, faith tradition, or admitting ICU. Operationalizing the MWM spirituality quality indicator was challenging as elements of a "spiritual screening" or documentation of a "spiritual discussion" were not clearly documented in the EMR. The high prevalence of spirituality among respondents validates the importance of spirituality as a potential quality metric. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All

Methodology for Evaluating Quality and Reusability of Learning Objects

ERIC Educational Resources Information Center

Kurilovas, Eugenijus; Bireniene, Virginija; Serikoviene, Silvija

2011-01-01

The aim of the paper is to present the scientific model and several methods for the expert evaluation of quality of learning objects (LOs) paying especial attention to LOs reusability level. The activities of eQNet Quality Network for a European Learning Resource Exchange (LRE) aimed to improve reusability of LOs of European Schoolnet's LRE…

Related Critical Psychometric Issues and Their Resolutions during Development of PE Metrics

ERIC Educational Resources Information Center

Fox, Connie; Zhu, Weimo; Park, Youngsik; Fisette, Jennifer L.; Graber, Kim C.; Dyson, Ben; Avery, Marybell; Franck, Marian; Placek, Judith H.; Rink, Judy; Raynes, De

2011-01-01

In addition to validity and reliability evidence, other psychometric qualities of the PE Metrics assessments needed to be examined. This article describes how those critical psychometric issues were addressed during the PE Metrics assessment bank construction. Specifically, issues included (a) number of items or assessments needed, (b) training…

SU-F-T-600: Influence of Acuros XB and AAA Dose Calculation Algorithms On Plan Quality Metrics and Normal Lung Doses in Lung SBRT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yaparpalvi, R; Mynampati, D; Kuo, H

Purpose: To study the influence of superposition-beam model (AAA) and determinant-photon transport-solver (Acuros XB) dose calculation algorithms on the treatment plan quality metrics and on normal lung dose in Lung SBRT. Methods: Treatment plans of 10 Lung SBRT patients were randomly selected. Patients were prescribed to a total dose of 50-54Gy in 3–5 fractions (10?5 or 18?3). Doses were optimized accomplished with 6-MV using 2-arcs (VMAT). Doses were calculated using AAA algorithm with heterogeneity correction. For each plan, plan quality metrics in the categories- coverage, homogeneity, conformity and gradient were quantified. Repeat dosimetry for these AAA treatment plans was performedmore » using AXB algorithm with heterogeneity correction for same beam and MU parameters. Plan quality metrics were again evaluated and compared with AAA plan metrics. For normal lung dose, V{sub 20} and V{sub 5} to (Total lung- GTV) were evaluated. Results: The results are summarized in Supplemental Table 1. PTV volume was mean 11.4 (±3.3) cm{sup 3}. Comparing RTOG 0813 protocol criteria for conformality, AXB plans yielded on average, similar PITV ratio (individual PITV ratio differences varied from −9 to +15%), reduced target coverage (−1.6%) and increased R50% (+2.6%). Comparing normal lung doses, the lung V{sub 20} (+3.1%) and V{sub 5} (+1.5%) were slightly higher for AXB plans compared to AAA plans. High-dose spillage ((V105%PD - PTV)/ PTV) was slightly lower for AXB plans but the % low dose spillage (D2cm) was similar between the two calculation algorithms. Conclusion: AAA algorithm overestimates lung target dose. Routinely adapting to AXB for dose calculations in Lung SBRT planning may improve dose calculation accuracy, as AXB based calculations have been shown to be closer to Monte Carlo based dose predictions in accuracy and with relatively faster computational time. For clinical practice, revisiting dose-fractionation in Lung SBRT to correct for dose

Intelligent Systems Approaches to Product Sound Quality Analysis

NASA Astrophysics Data System (ADS)

Pietila, Glenn M.

As a product market becomes more competitive, consumers become more discriminating in the way in which they differentiate between engineered products. The consumer often makes a purchasing decision based on the sound emitted from the product during operation by using the sound to judge quality or annoyance. Therefore, in recent years, many sound quality analysis tools have been developed to evaluate the consumer preference as it relates to a product sound and to quantify this preference based on objective measurements. This understanding can be used to direct a product design process in order to help differentiate the product from competitive products or to establish an impression on consumers regarding a product's quality or robustness. The sound quality process is typically a statistical tool that is used to model subjective preference, or merit score, based on objective measurements, or metrics. In this way, new product developments can be evaluated in an objective manner without the laborious process of gathering a sample population of consumers for subjective studies each time. The most common model used today is the Multiple Linear Regression (MLR), although recently non-linear Artificial Neural Network (ANN) approaches are gaining popularity. This dissertation will review publicly available published literature and present additional intelligent systems approaches that can be used to improve on the current sound quality process. The focus of this work is to address shortcomings in the current paired comparison approach to sound quality analysis. This research will propose a framework for an adaptive jury analysis approach as an alternative to the current Bradley-Terry model. The adaptive jury framework uses statistical hypothesis testing to focus on sound pairings that are most interesting and is expected to address some of the restrictions required by the Bradley-Terry model. It will also provide a more amicable framework for an intelligent systems approach

Sigma Routing Metric for RPL Protocol.

PubMed

Sanmartin, Paul; Rojas, Aldo; Fernandez, Luis; Avila, Karen; Jabba, Daladier; Valle, Sebastian

2018-04-21

This paper presents the adaptation of a specific metric for the RPL protocol in the objective function MRHOF. Among the functions standardized by IETF, we find OF0, which is based on the minimum hop count, as well as MRHOF, which is based on the Expected Transmission Count (ETX). However, when the network becomes denser or the number of nodes increases, both OF0 and MRHOF introduce long hops, which can generate a bottleneck that restricts the network. The adaptation is proposed to optimize both OFs through a new routing metric. To solve the above problem, the metrics of the minimum number of hops and the ETX are combined by designing a new routing metric called SIGMA-ETX, in which the best route is calculated using the standard deviation of ETX values between each node, as opposed to working with the ETX average along the route. This method ensures a better routing performance in dense sensor networks. The simulations are done through the Cooja simulator, based on the Contiki operating system. The simulations showed that the proposed optimization outperforms at a high margin in both OF0 and MRHOF, in terms of network latency, packet delivery ratio, lifetime, and power consumption.

Sigma Routing Metric for RPL Protocol

PubMed Central

Rojas, Aldo; Fernandez, Luis

2018-01-01

This paper presents the adaptation of a specific metric for the RPL protocol in the objective function MRHOF. Among the functions standardized by IETF, we find OF0, which is based on the minimum hop count, as well as MRHOF, which is based on the Expected Transmission Count (ETX). However, when the network becomes denser or the number of nodes increases, both OF0 and MRHOF introduce long hops, which can generate a bottleneck that restricts the network. The adaptation is proposed to optimize both OFs through a new routing metric. To solve the above problem, the metrics of the minimum number of hops and the ETX are combined by designing a new routing metric called SIGMA-ETX, in which the best route is calculated using the standard deviation of ETX values between each node, as opposed to working with the ETX average along the route. This method ensures a better routing performance in dense sensor networks. The simulations are done through the Cooja simulator, based on the Contiki operating system. The simulations showed that the proposed optimization outperforms at a high margin in both OF0 and MRHOF, in terms of network latency, packet delivery ratio, lifetime, and power consumption. PMID:29690524

Perceptual color difference metric including a CSF based on the perception threshold

NASA Astrophysics Data System (ADS)

Rosselli, Vincent; Larabi, Mohamed-Chaker; Fernandez-Maloigne, Christine

2008-01-01

The study of the Human Visual System (HVS) is very interesting to quantify the quality of a picture, to predict which information will be perceived on it, to apply adapted tools ... The Contrast Sensitivity Function (CSF) is one of the major ways to integrate the HVS properties into an imaging system. It characterizes the sensitivity of the visual system to spatial and temporal frequencies and predicts the behavior for the three channels. Common constructions of the CSF have been performed by estimating the detection threshold beyond which it is possible to perceive a stimulus. In this work, we developed a novel approach for spatio-chromatic construction based on matching experiments to estimate the perception threshold. It consists in matching the contrast of a test stimulus with that of a reference one. The obtained results are quite different in comparison with the standard approaches as the chromatic CSFs have band-pass behavior and not low pass. The obtained model has been integrated in a perceptual color difference metric inspired by the s-CIELAB. The metric is then evaluated with both objective and subjective procedures.

Quality and Content of Individualized Habilitation Plan Objectives in Residential Settings.

ERIC Educational Resources Information Center

Stancliffe, Roger J.; Hayden, Mary F.; Lakin, K. Charlie

2000-01-01

The quality, number, and content of residential Individualized Habilitation Plans (IHP) objectives were evaluated for 155 adult institution and community residents. Over 90 percent of objectives were functional and age appropriate. Community residents had significantly more IHP objectives and also had objectives from a wider variety of content…

Comparison of employer productivity metrics to lost productivity estimated by commonly used questionnaires

PubMed Central

Gardner, Bethany T.; Dale, Ann Marie; Buckner-Petty, Skye; Van Dillen, Linda; Amick, Benjamin C.; Evanoff, Bradley

2016-01-01

Objective To assess construct and discriminant validity of four health-related work productivity loss questionnaires in relation to employer productivity metrics, and to describe variation in economic estimates of productivity loss provided by the questionnaires in healthy workers. Methods 58 billing office workers completed surveys including health information and four productivity loss questionnaires. Employer productivity metrics and work hours were also obtained. Results Productivity loss questionnaires were weakly to moderately correlated with employer productivity metrics. Workers with more health complaints reported greater health-related productivity loss than healthier workers, but showed no loss on employer productivity metrics. Economic estimates of productivity loss showed wide variation among questionnaires, yet no loss of actual productivity. Conclusions Additional studies are needed comparing questionnaires with objective measures in larger samples and other industries, to improve measurement methods for health-related productivity loss. PMID:26849261

The data quality analyzer: a quality control program for seismic data

USGS Publications Warehouse

Ringler, Adam; Hagerty, M.T.; Holland, James F.; Gonzales, A.; Gee, Lind S.; Edwards, J.D.; Wilson, David; Baker, Adam

2015-01-01

The quantification of data quality is based on the evaluation of various metrics (e.g., timing quality, daily noise levels relative to long-term noise models, and comparisons between broadband data and event synthetics). Users may select which metrics contribute to the assessment and those metrics are aggregated into a “grade” for each station. The DQA is being actively used for station diagnostics and evaluation based on the completed metrics (availability, gap count, timing quality, deviation from a global noise model, deviation from a station noise model, coherence between co-located sensors, and comparison between broadband data and synthetics for earthquakes) on stations in the Global Seismographic Network and Advanced National Seismic System.

Adapting the ISO 20462 softcopy ruler method for online image quality studies

NASA Astrophysics Data System (ADS)

Burns, Peter D.; Phillips, Jonathan B.; Williams, Don

2013-01-01

In this paper we address the problem of Image Quality Assessment of no reference metrics, focusing on JPEG corrupted images. In general no reference metrics are not able to measure with the same performance the distortions within their possible range and with respect to different image contents. The crosstalk between content and distortion signals influences the human perception. We here propose two strategies to improve the correlation between subjective and objective quality data. The first strategy is based on grouping the images according to their spatial complexity. The second one is based on a frequency analysis. Both the strategies are tested on two databases available in the literature. The results show an improvement in the correlations between no reference metrics and psycho-visual data, evaluated in terms of the Pearson Correlation Coefficient.

NASA metric transition plan

NASA Technical Reports Server (NTRS)

1992-01-01

NASA science publications have used the metric system of measurement since 1970. Although NASA has maintained a metric use policy since 1979, practical constraints have restricted actual use of metric units. In 1988, an amendment to the Metric Conversion Act of 1975 required the Federal Government to adopt the metric system except where impractical. In response to Public Law 100-418 and Executive Order 12770, NASA revised its metric use policy and developed this Metric Transition Plan. NASA's goal is to use the metric system for program development and functional support activities to the greatest practical extent by the end of 1995. The introduction of the metric system into new flight programs will determine the pace of the metric transition. Transition of institutional capabilities and support functions will be phased to enable use of the metric system in flight program development and operations. Externally oriented elements of this plan will introduce and actively support use of the metric system in education, public information, and small business programs. The plan also establishes a procedure for evaluating and approving waivers and exceptions to the required use of the metric system for new programs. Coordination with other Federal agencies and departments (through the Interagency Council on Metric Policy) and industry (directly and through professional societies and interest groups) will identify sources of external support and minimize duplication of effort.

The Aspects About of Objectively Appraisals of Modeling Gypsum Quality and Composites of Phonic-Absorbent and Orthopedic on Base of Gypsum

NASA Astrophysics Data System (ADS)

Pop, P. A.; Ungur, P. A.; Lazar, L.; Marcu, F.

2009-11-01

The EU Norms about of protection environment, outside and inside ambient, and human health demands has lead at obtain of new materials on the base of airborne material, with high thermo and phonic-absorbent properties, porous and lightweight. The α and β-modeling gypsum plaster quality and lightweight depend on many factors as: fabrication process, granulation, roast temperature, work temperature, environment, additives used, breakage, etc. Also, the objectively appraisal of modeling gypsum quality depends of proper tests methods selection, which are legislated in norms, standards and recommendations. In Romanian Standards SR EN 13279-1/2005 and SR EN 13279-2/2005, adaptable from EU Norms EN 13279-1/2004 and EN 13279-2/2004, the characteristics gypsum family tests are well specification, as: granule-metric analysis, determination of water/plaster ratio, setting time, mechanical characteristics, adhesions and water restrain. For plaster with special use (phonic-absorbent and orthopedic materials, etc.) these determinations are not concluding, being necessary more parameters finding, as: elastic constant, phonic-absorbent coefficient, porosity, working, etc., which is imposed the completion of norms and standards with new determinations.

Objective quality assessment of tone-mapped images.

PubMed

Yeganeh, Hojatollah; Wang, Zhou

2013-02-01

Tone-mapping operators (TMOs) that convert high dynamic range (HDR) to low dynamic range (LDR) images provide practically useful tools for the visualization of HDR images on standard LDR displays. Different TMOs create different tone-mapped images, and a natural question is which one has the best quality. Without an appropriate quality measure, different TMOs cannot be compared, and further improvement is directionless. Subjective rating may be a reliable evaluation method, but it is expensive and time consuming, and more importantly, is difficult to be embedded into optimization frameworks. Here we propose an objective quality assessment algorithm for tone-mapped images by combining: 1) a multiscale signal fidelity measure on the basis of a modified structural similarity index and 2) a naturalness measure on the basis of intensity statistics of natural images. Validations using independent subject-rated image databases show good correlations between subjective ranking score and the proposed tone-mapped image quality index (TMQI). Furthermore, we demonstrate the extended applications of TMQI using two examples-parameter tuning for TMOs and adaptive fusion of multiple tone-mapped images.

Early Warning Look Ahead Metrics: The Percent Milestone Backlog Metric

NASA Technical Reports Server (NTRS)

Shinn, Stephen A.; Anderson, Timothy P.

2017-01-01

All complex development projects experience delays and corresponding backlogs of their project control milestones during their acquisition lifecycles. NASA Goddard Space Flight Center (GSFC) Flight Projects Directorate (FPD) teamed with The Aerospace Corporation (Aerospace) to develop a collection of Early Warning Look Ahead metrics that would provide GSFC leadership with some independent indication of the programmatic health of GSFC flight projects. As part of the collection of Early Warning Look Ahead metrics, the Percent Milestone Backlog metric is particularly revealing, and has utility as a stand-alone execution performance monitoring tool. This paper describes the purpose, development methodology, and utility of the Percent Milestone Backlog metric. The other four Early Warning Look Ahead metrics are also briefly discussed. Finally, an example of the use of the Percent Milestone Backlog metric in providing actionable insight is described, along with examples of its potential use in other commodities.

Clinical Outcome Metrics for Optimization of Robust Training

NASA Technical Reports Server (NTRS)

Ebert, Doug; Byrne, Vicky; Cole, Richard; Dulchavsky, Scott; Foy, Millennia; Garcia, Kathleen; Gibson, Robert; Ham, David; Hurst, Victor; Kerstman, Eric;

Center to Advance Palliative Care palliative care clinical care and customer satisfaction metrics consensus recommendations.

PubMed

Weissman, David E; Morrison, R Sean; Meier, Diane E

2010-02-01

Data collection and analysis are vital for strategic planning, quality improvement, and demonstration of palliative care program impact to hospital administrators, private funders and policymakers. Since 2000, the Center to Advance Palliative Care (CAPC) has provided technical assistance to hospitals, health systems and hospices working to start, sustain, and grow nonhospice palliative care programs. CAPC convened a consensus panel in 2008 to develop recommendations for specific clinical and customer metrics that programs should track. The panel agreed on four key domains of clinical metrics and two domains of customer metrics. Clinical metrics include: daily assessment of physical/psychological/spiritual symptoms by a symptom assessment tool; establishment of patient-centered goals of care; support to patient/family caregivers; and management of transitions across care sites. For customer metrics, consensus was reached on two domains that should be tracked to assess satisfaction: patient/family satisfaction, and referring clinician satisfaction. In an effort to ensure access to reliably high-quality palliative care data throughout the nation, hospital palliative care programs are encouraged to collect and report outcomes for each of the metric domains described here.

Exploring s-CIELAB as a scanner metric for print uniformity

NASA Astrophysics Data System (ADS)

Hertel, Dirk W.

2005-01-01

The s-CIELAB color difference metric combines the standard CIELAB metric for perceived color difference with spatial contrast sensitivity filtering. When studying the performance of digital image processing algorithms, maps of spatial color difference between 'before' and 'after' images are a measure of perceived image difference. A general image quality metric can be obtained by modeling the perceived difference from an ideal image. This paper explores the s-CIELAB concept for evaluating the quality of digital prints. Prints present the challenge that the 'ideal print' which should serve as the reference when calculating the delta E* error map is unknown, and thus be estimated from the scanned print. A reasonable estimate of what the ideal print 'should have been' is possible at least for images of known content such as flat fields or continuous wedges, where the error map can be calculated against a global or local mean. While such maps showing the perceived error at each pixel are extremely useful when analyzing print defects, it is desirable to statistically reduce them to a more manageable dataset. Examples of digital print uniformity are given, and the effect of specific print defects on the s-CIELAB delta E* metric are discussed.

Prioritizing Urban Habitats for Connectivity Conservation: Integrating Centrality and Ecological Metrics.

PubMed

Poodat, Fatemeh; Arrowsmith, Colin; Fraser, David; Gordon, Ascelin

2015-09-01

Connectivity among fragmented areas of habitat has long been acknowledged as important for the viability of biological conservation, especially within highly modified landscapes. Identifying important habitat patches in ecological connectivity is a priority for many conservation strategies, and the application of 'graph theory' has been shown to provide useful information on connectivity. Despite the large number of metrics for connectivity derived from graph theory, only a small number have been compared in terms of the importance they assign to nodes in a network. This paper presents a study that aims to define a new set of metrics and compares these with traditional graph-based metrics, used in the prioritization of habitat patches for ecological connectivity. The metrics measured consist of "topological" metrics, "ecological metrics," and "integrated metrics," Integrated metrics are a combination of topological and ecological metrics. Eight metrics were applied to the habitat network for the fat-tailed dunnart within Greater Melbourne, Australia. A non-directional network was developed in which nodes were linked to adjacent nodes. These links were then weighted by the effective distance between patches. By applying each of the eight metrics for the study network, nodes were ranked according to their contribution to the overall network connectivity. The structured comparison revealed the similarity and differences in the way the habitat for the fat-tailed dunnart was ranked based on different classes of metrics. Due to the differences in the way the metrics operate, a suitable metric should be chosen that best meets the objectives established by the decision maker.

Backward Registration Based Aspect Ratio Similarity (ARS) for Image Retargeting Quality Assessment.

PubMed

Zhang, Yabin; Fang, Yuming; Lin, Weisi; Zhang, Xinfeng; Li, Leida

2016-06-28

During the past few years, there have been various kinds of content-aware image retargeting operators proposed for image resizing. However, the lack of effective objective retargeting quality assessment metrics limits the further development of image retargeting techniques. Different from traditional Image Quality Assessment (IQA) metrics, the quality degradation during image retargeting is caused by artificial retargeting modifications, and the difficulty for Image Retargeting Quality Assessment (IRQA) lies in the alternation of the image resolution and content, which makes it impossible to directly evaluate the quality degradation like traditional IQA. In this paper, we interpret the image retargeting in a unified framework of resampling grid generation and forward resampling. We show that the geometric change estimation is an efficient way to clarify the relationship between the images. We formulate the geometric change estimation as a Backward Registration problem with Markov Random Field (MRF) and provide an effective solution. The geometric change aims to provide the evidence about how the original image is resized into the target image. Under the guidance of the geometric change, we develop a novel Aspect Ratio Similarity metric (ARS) to evaluate the visual quality of retargeted images by exploiting the local block changes with a visual importance pooling strategy. Experimental results on the publicly available MIT RetargetMe and CUHK datasets demonstrate that the proposed ARS can predict more accurate visual quality of retargeted images compared with state-of-the-art IRQA metrics.

Introduction to the special collection of papers on the San Luis Basin Sustainability Metrics Project: a methodology for evaluating regional sustainability.

PubMed

Heberling, Matthew T; Hopton, Matthew E

2012-11-30

This paper introduces a collection of four articles describing the San Luis Basin Sustainability Metrics Project. The Project developed a methodology for evaluating regional sustainability. This introduction provides the necessary background information for the project, description of the region, overview of the methods, and summary of the results. Although there are a multitude of scientifically based sustainability metrics, many are data intensive, difficult to calculate, and fail to capture all aspects of a system. We wanted to see if we could develop an approach that decision-makers could use to understand if their system was moving toward or away from sustainability. The goal was to produce a scientifically defensible, but straightforward and inexpensive methodology to measure and monitor environmental quality within a regional system. We initiated an interdisciplinary pilot project in the San Luis Basin, south-central Colorado, to test the methodology. The objectives were: 1) determine the applicability of using existing datasets to estimate metrics of sustainability at a regional scale; 2) calculate metrics through time from 1980 to 2005; and 3) compare and contrast the results to determine if the system was moving toward or away from sustainability. The sustainability metrics, chosen to represent major components of the system, were: 1) Ecological Footprint to capture the impact and human burden on the system; 2) Green Net Regional Product to represent economic welfare; 3) Emergy to capture the quality-normalized flow of energy through the system; and 4) Fisher information to capture the overall dynamic order and to look for possible regime changes. The methodology, data, and results of each metric are presented in the remaining four papers of the special collection. Based on the results of each metric and our criteria for understanding the sustainability trends, we find that the San Luis Basin is moving away from sustainability. Although we understand

Reduced reference image quality assessment via sub-image similarity based redundancy measurement

NASA Astrophysics Data System (ADS)

Mou, Xuanqin; Xue, Wufeng; Zhang, Lei

2012-03-01

The reduced reference (RR) image quality assessment (IQA) has been attracting much attention from researchers for its loyalty to human perception and flexibility in practice. A promising RR metric should be able to predict the perceptual quality of an image accurately while using as few features as possible. In this paper, a novel RR metric is presented, whose novelty lies in two aspects. Firstly, it measures the image redundancy by calculating the so-called Sub-image Similarity (SIS), and the image quality is measured by comparing the SIS between the reference image and the test image. Secondly, the SIS is computed by the ratios of NSE (Non-shift Edge) between pairs of sub-images. Experiments on two IQA databases (i.e. LIVE and CSIQ databases) show that by using only 6 features, the proposed metric can work very well with high correlations between the subjective and objective scores. In particular, it works consistently well across all the distortion types.

Quality-of-life metrics with vagus nerve stimulation for epilepsy from provider survey data.

PubMed

Englot, Dario J; Hassnain, Kevin H; Rolston, John D; Harward, Stephen C; Sinha, Saurabh R; Haglund, Michael M

2017-01-01

Drug-resistant epilepsy is a devastating disorder associated with diminished quality of life (QOL). Surgical resection leads to seizure freedom and improved QOL in many epilepsy patients, but not all individuals are candidates for resection. In these cases, neuromodulation-based therapies such as vagus nerve stimulation (VNS) are often used, but most VNS studies focus exclusively on reduction of seizure frequency. QOL changes and predictors with VNS remain poorly understood. Using the VNS Therapy Patient Outcome Registry, we examined 7 metrics related to QOL after VNS for epilepsy in over 5000 patients (including over 3000 with ≥12months follow-up), as subjectively assessed by treating physicians. Trends and predictors of QOL changes were examined and related to post-operative seizure outcome and likelihood of VNS generator replacement. After VNS therapy, physicians reported patient improvement in alertness (58-63%, range over follow-up period), post-ictal state (55-62%), cluster seizures (48-56%), mood change (43-49%), verbal communication (38-45%), school/professional achievements (29-39%), and memory (29-38%). Predictors of net QOL improvement included shorter time to implant (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.1-1.6), generalized seizure type (OR, 1.2; 95% CI, 1.0-1.4), female gender (OR, 1.2; 95% CI, 1.0-1.4), and Caucasian ethnicity (OR, 1.3; 95% CI, 1.0-1.5). No significant trends were observed over time. Patients with net QOL improvement were more likely to have favorable seizure outcomes (chi square [χ 2 ]=148.1, p<0.001) and more likely to undergo VNS generator replacement (χ 2 =68.9, p<0.001) than those with worsened/unchanged QOL. VNS for drug-resistant epilepsy is associated with improvement on various QOL metrics subjectively rated by physicians. QOL improvement is associated with favorable seizure outcome and a higher likelihood of generator replacement, suggesting satisfaction with therapy. It is important to consider QOL

Evaluation Metrics for Biostatistical and Epidemiological Collaborations

PubMed Central

Rubio, Doris McGartland; del Junco, Deborah J.; Bhore, Rafia; Lindsell, Christopher J.; Oster, Robert A.; Wittkowski, Knut M.; Welty, Leah J.; Li, Yi-Ju; DeMets, Dave

2011-01-01

Increasing demands for evidence-based medicine and for the translation of biomedical research into individual and public health benefit have been accompanied by the proliferation of special units that offer expertise in biostatistics, epidemiology, and research design (BERD) within academic health centers. Objective metrics that can be used to evaluate, track, and improve the performance of these BERD units are critical to their successful establishment and sustainable future. To develop a set of reliable but versatile metrics that can be adapted easily to different environments and evolving needs, we consulted with members of BERD units from the consortium of academic health centers funded by the Clinical and Translational Science Award Program of the National Institutes of Health. Through a systematic process of consensus building and document drafting, we formulated metrics that covered the three identified domains of BERD practices: the development and maintenance of collaborations with clinical and translational science investigators, the application of BERD-related methods to clinical and translational research, and the discovery of novel BERD-related methodologies. In this article, we describe the set of metrics and advocate their use for evaluating BERD practices. The routine application, comparison of findings across diverse BERD units, and ongoing refinement of the metrics will identify trends, facilitate meaningful changes, and ultimately enhance the contribution of BERD activities to biomedical research. PMID:21284015

Evaluation metrics for biostatistical and epidemiological collaborations.

PubMed

Rubio, Doris McGartland; Del Junco, Deborah J; Bhore, Rafia; Lindsell, Christopher J; Oster, Robert A; Wittkowski, Knut M; Welty, Leah J; Li, Yi-Ju; Demets, Dave

2011-10-15

Increasing demands for evidence-based medicine and for the translation of biomedical research into individual and public health benefit have been accompanied by the proliferation of special units that offer expertise in biostatistics, epidemiology, and research design (BERD) within academic health centers. Objective metrics that can be used to evaluate, track, and improve the performance of these BERD units are critical to their successful establishment and sustainable future. To develop a set of reliable but versatile metrics that can be adapted easily to different environments and evolving needs, we consulted with members of BERD units from the consortium of academic health centers funded by the Clinical and Translational Science Award Program of the National Institutes of Health. Through a systematic process of consensus building and document drafting, we formulated metrics that covered the three identified domains of BERD practices: the development and maintenance of collaborations with clinical and translational science investigators, the application of BERD-related methods to clinical and translational research, and the discovery of novel BERD-related methodologies. In this article, we describe the set of metrics and advocate their use for evaluating BERD practices. The routine application, comparison of findings across diverse BERD units, and ongoing refinement of the metrics will identify trends, facilitate meaningful changes, and ultimately enhance the contribution of BERD activities to biomedical research. Copyright © 2011 John Wiley & Sons, Ltd.

A Metric-Based Validation Process to Assess the Realism of Synthetic Power Grids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birchfield, Adam; Schweitzer, Eran; Athari, Mir

Public power system test cases that are of high quality benefit the power systems research community with expanded resources for testing, demonstrating, and cross-validating new innovations. Building synthetic grid models for this purpose is a relatively new problem, for which a challenge is to show that created cases are sufficiently realistic. This paper puts forth a validation process based on a set of metrics observed from actual power system cases. These metrics follow the structure, proportions, and parameters of key power system elements, which can be used in assessing and validating the quality of synthetic power grids. Though wide diversitymore » exists in the characteristics of power systems, the paper focuses on an initial set of common quantitative metrics to capture the distribution of typical values from real power systems. The process is applied to two new public test cases, which are shown to meet the criteria specified in the metrics of this paper.« less

A Metric-Based Validation Process to Assess the Realism of Synthetic Power Grids

DOE PAGES

Birchfield, Adam; Schweitzer, Eran; Athari, Mir; ...

2017-08-19

Public power system test cases that are of high quality benefit the power systems research community with expanded resources for testing, demonstrating, and cross-validating new innovations. Building synthetic grid models for this purpose is a relatively new problem, for which a challenge is to show that created cases are sufficiently realistic. This paper puts forth a validation process based on a set of metrics observed from actual power system cases. These metrics follow the structure, proportions, and parameters of key power system elements, which can be used in assessing and validating the quality of synthetic power grids. Though wide diversitymore » exists in the characteristics of power systems, the paper focuses on an initial set of common quantitative metrics to capture the distribution of typical values from real power systems. The process is applied to two new public test cases, which are shown to meet the criteria specified in the metrics of this paper.« less

Measuring economic complexity of countries and products: which metric to use?

NASA Astrophysics Data System (ADS)

Mariani, Manuel Sebastian; Vidmer, Alexandre; Medo, Matsúš; Zhang, Yi-Cheng

2015-11-01

Evaluating the economies of countries and their relations with products in the global market is a central problem in economics, with far-reaching implications to our theoretical understanding of the international trade as well as to practical applications, such as policy making and financial investment planning. The recent Economic Complexity approach aims to quantify the competitiveness of countries and the quality of the exported products based on the empirical observation that the most competitive countries have diversified exports, whereas developing countries only export few low quality products - typically those exported by many other countries. Two different metrics, Fitness-Complexity and the Method of Reflections, have been proposed to measure country and product score in the Economic Complexity framework. We use international trade data and a recent ranking evaluation measure to quantitatively compare the ability of the two metrics to rank countries and products according to their importance in the network. The results show that the Fitness-Complexity metric outperforms the Method of Reflections in both the ranking of products and the ranking of countries. We also investigate a generalization of the Fitness-Complexity metric and show that it can produce improved rankings provided that the input data are reliable.

The LSST Metrics Analysis Framework (MAF)

NASA Astrophysics Data System (ADS)

Jones, R. Lynne; Yoachim, Peter; Chandrasekharan, Srinivasan; Connolly, Andrew J.; Cook, Kem H.; Ivezic, Zeljko; Krughoff, K. Simon; Petry, Catherine E.; Ridgway, Stephen T.

2015-01-01

Studying potential observing strategies or cadences for the Large Synoptic Survey Telescope (LSST) is a complicated but important problem. To address this, LSST has created an Operations Simulator (OpSim) to create simulated surveys, including realistic weather and sky conditions. Analyzing the results of these simulated surveys for the wide variety of science cases to be considered for LSST is, however, difficult. We have created a Metric Analysis Framework (MAF), an open-source python framework, to be a user-friendly, customizable and easily extensible tool to help analyze the outputs of the OpSim.MAF reads the pointing history of the LSST generated by the OpSim, then enables the subdivision of these pointings based on position on the sky (RA/Dec, etc.) or the characteristics of the observations (e.g. airmass or sky brightness) and a calculation of how well these observations meet a specified science objective (or metric). An example simple metric could be the mean single visit limiting magnitude for each position in the sky; a more complex metric might be the expected astrometric precision. The output of these metrics can be generated for a full survey, for specified time intervals, or for regions of the sky, and can be easily visualized using a web interface.An important goal for MAF is to facilitate analysis of the OpSim outputs for a wide variety of science cases. A user can often write a new metric to evaluate OpSim for new science goals in less than a day once they are familiar with the framework. Some of these new metrics are illustrated in the accompanying poster, "Analyzing Simulated LSST Survey Performance With MAF".While MAF has been developed primarily for application to OpSim outputs, it can be applied to any dataset. The most obvious examples are examining pointing histories of other survey projects or telescopes, such as CFHT.

An Opportunistic Routing Mechanism Combined with Long-Term and Short-Term Metrics for WMN

PubMed Central

Piao, Xianglan; Qiu, Tie

2014-01-01

WMN (wireless mesh network) is a useful wireless multihop network with tremendous research value. The routing strategy decides the performance of network and the quality of transmission. A good routing algorithm will use the whole bandwidth of network and assure the quality of service of traffic. Since the routing metric ETX (expected transmission count) does not assure good quality of wireless links, to improve the routing performance, an opportunistic routing mechanism combined with long-term and short-term metrics for WMN based on OLSR (optimized link state routing) and ETX is proposed in this paper. This mechanism always chooses the highest throughput links to improve the performance of routing over WMN and then reduces the energy consumption of mesh routers. The simulations and analyses show that the opportunistic routing mechanism is better than the mechanism with the metric of ETX. PMID:25250379

An opportunistic routing mechanism combined with long-term and short-term metrics for WMN.

PubMed

Sun, Weifeng; Wang, Haotian; Piao, Xianglan; Qiu, Tie

2014-01-01

WMN (wireless mesh network) is a useful wireless multihop network with tremendous research value. The routing strategy decides the performance of network and the quality of transmission. A good routing algorithm will use the whole bandwidth of network and assure the quality of service of traffic. Since the routing metric ETX (expected transmission count) does not assure good quality of wireless links, to improve the routing performance, an opportunistic routing mechanism combined with long-term and short-term metrics for WMN based on OLSR (optimized link state routing) and ETX is proposed in this paper. This mechanism always chooses the highest throughput links to improve the performance of routing over WMN and then reduces the energy consumption of mesh routers. The simulations and analyses show that the opportunistic routing mechanism is better than the mechanism with the metric of ETX.

A system to program projects to meet visual quality objectives

Treesearch

Fred L. Henley; Frank L. Hunsaker

1979-01-01

The U. S. Forest Service has established Visual Quality Objectives for National Forest lands and determined a method to ascertain the Visual Absorption Capability of those lands. Combining the two mapping inventories has allowed the Forest Service to retain the visual quality while managing natural resources.

Making the Case for Objective Performance Metrics in Newborn Screening by Tandem Mass Spectrometry

ERIC Educational Resources Information Center

Rinaldo, Piero; Zafari, Saba; Tortorelli, Silvia; Matern, Dietrich

2006-01-01

The expansion of newborn screening programs to include multiplex testing by tandem mass spectrometry requires understanding and close monitoring of performance metrics. This is not done consistently because of lack of defined targets, and interlaboratory comparison is almost nonexistent. Between July 2004 and April 2006 (N = 176,185 cases), the…

Projector-Based Augmented Reality for Quality Inspection of Scanned Objects

NASA Astrophysics Data System (ADS)

Kern, J.; Weinmann, M.; Wursthorn, S.

2017-09-01

After scanning or reconstructing the geometry of objects, we need to inspect the result of our work. Are there any parts missing? Is every detail covered in the desired quality? We typically do this by looking at the resulting point clouds or meshes of our objects on-screen. What, if we could see the information directly visualized on the object itself? Augmented reality is the generic term for bringing virtual information into our real environment. In our paper, we show how we can project any 3D information like thematic visualizations or specific monitoring information with reference to our object onto the object's surface itself, thus augmenting it with additional information. For small objects that could for instance be scanned in a laboratory, we propose a low-cost method involving a projector-camera system to solve this task. The user only needs a calibration board with coded fiducial markers to calibrate the system and to estimate the projector's pose later on for projecting textures with information onto the object's surface. Changes within the projected 3D information or of the projector's pose will be applied in real-time. Our results clearly reveal that such a simple setup will deliver a good quality of the augmented information.

It's A Metric World.

ERIC Educational Resources Information Center

Alabama State Dept. of Education, Montgomery. Div. of Instructional Services.

Topics covered in the first part of this document include eight advantages of the metric system; a summary of metric instruction; the International System of Units (SI) style and usage; metric decimal tables; the metric system; and conversion tables. An alphabetized list of organizations which market metric materials for educators is provided with…

Sigma Metrics Across the Total Testing Process.

PubMed

Charuruks, Navapun

2017-03-01

Laboratory quality control has been developed for several decades to ensure patients' safety, from a statistical quality control focus on the analytical phase to total laboratory processes. The sigma concept provides a convenient way to quantify the number of errors in extra-analytical and analytical phases through the defect per million and sigma metric equation. Participation in a sigma verification program can be a convenient way to monitor analytical performance continuous quality improvement. Improvement of sigma-scale performance has been shown from our data. New tools and techniques for integration are needed. Copyright © 2016 Elsevier Inc. All rights reserved.

Relevance of motion-related assessment metrics in laparoscopic surgery.

PubMed

Oropesa, Ignacio; Chmarra, Magdalena K; Sánchez-González, Patricia; Lamata, Pablo; Rodrigues, Sharon P; Enciso, Silvia; Sánchez-Margallo, Francisco M; Jansen, Frank-Willem; Dankelman, Jenny; Gómez, Enrique J

2013-06-01

Motion metrics have become an important source of information when addressing the assessment of surgical expertise. However, their direct relationship with the different surgical skills has not been fully explored. The purpose of this study is to investigate the relevance of motion-related metrics in the evaluation processes of basic psychomotor laparoscopic skills and their correlation with the different abilities sought to measure. A framework for task definition and metric analysis is proposed. An explorative survey was first conducted with a board of experts to identify metrics to assess basic psychomotor skills. Based on the output of that survey, 3 novel tasks for surgical assessment were designed. Face and construct validation was performed, with focus on motion-related metrics. Tasks were performed by 42 participants (16 novices, 22 residents, and 4 experts). Movements of the laparoscopic instruments were registered with the TrEndo tracking system and analyzed. Time, path length, and depth showed construct validity for all 3 tasks. Motion smoothness and idle time also showed validity for tasks involving bimanual coordination and tasks requiring a more tactical approach, respectively. Additionally, motion smoothness and average speed showed a high internal consistency, proving them to be the most task-independent of all the metrics analyzed. Motion metrics are complementary and valid for assessing basic psychomotor skills, and their relevance depends on the skill being evaluated. A larger clinical implementation, combined with quality performance information, will give more insight on the relevance of the results shown in this study.

Developing a more useful surface quality metric for laser optics

NASA Astrophysics Data System (ADS)

Turchette, Quentin; Turner, Trey

2011-02-01

Light scatter due to surface defects on laser resonator optics produces losses which lower system efficiency and output power. The traditional methodology for surface quality inspection involves visual comparison of a component to scratch and dig (SAD) standards under controlled lighting and viewing conditions. Unfortunately, this process is subjective and operator dependent. Also, there is no clear correlation between inspection results and the actual performance impact of the optic in a laser resonator. As a result, laser manufacturers often overspecify surface quality in order to ensure that optics will not degrade laser performance due to scatter. This can drive up component costs and lengthen lead times. Alternatively, an objective test system for measuring optical scatter from defects can be constructed with a microscope, calibrated lighting, a CCD detector and image processing software. This approach is quantitative, highly repeatable and totally operator independent. Furthermore, it is flexible, allowing the user to set threshold levels as to what will or will not constitute a defect. This paper details how this automated, quantitative type of surface quality measurement can be constructed, and shows how its results correlate against conventional loss measurement techniques such as cavity ringdown times.

Objective Biomarkers of Balance and Gait for Parkinson’s Disease using Body-worn Sensors

PubMed Central

Horak, Fay B; Mancini, Martina

2014-01-01

Balance and gait impairments characterize progression of Parkinson’s disease (PD), predict fall risk, and are important contributors to reduced quality of life. Advances in technology of small, body-worn inertial sensors have made it possible to develop quick, objective measures of balance and gait impairments in the clinic for research trials and clinical practice. Objective balance and gait metrics may eventually provide useful biomarkers for PD. In fact, objective balance and gait measures are already being used as surrogate end-points for demonstrating clinical efficacy of new treatments, in place of counting falls from diaries, using stop-watch measures of gait speed, or clinical balance rating scales. This review summarizes the types of objective measures available from body-worn sensors. We organize the metrics based on the neural control system for mobility affected by PD: postural stability in stance, postural responses, gait initiation, gait (temporal-spatial lower and upper body coordination and dynamic equilibrium), postural transitions, and freezing of gait. However, the explosion of metrics derived by wearable sensors during prescribed balance and gait tasks that are abnormal in people with PD do not yet qualify as behavioral biomarkers because many balance and gait impairments observed in PD are not specific to the disease, nor shown to be related to specific pathophysiologic biomarkers. In the future, the most useful balance and gait biomarkers for PD will be those that are sensitive and specific for early PD and related to the underlying disease process. PMID:24132842

Development of quality metrics for ambulatory pediatric cardiology: Chest pain.

PubMed

Lu, Jimmy C; Bansal, Manish; Behera, Sarina K; Boris, Jeffrey R; Cardis, Brian; Hokanson, John S; Kakavand, Bahram; Jedeikin, Roy

2017-12-01

As part of the American College of Cardiology Adult Congenital and Pediatric Cardiology Section effort to develop quality metrics (QMs) for ambulatory pediatric practice, the chest pain subcommittee aimed to develop QMs for evaluation of chest pain. A group of 8 pediatric cardiologists formulated candidate QMs in the areas of history, physical examination, and testing. Consensus candidate QMs were submitted to an expert panel for scoring by the RAND-UCLA modified Delphi process. Recommended QMs were then available for open comments from all members. These QMs are intended for use in patients 5-18 years old, referred for initial evaluation of chest pain in an ambulatory pediatric cardiology clinic, with no known history of pediatric or congenital heart disease. A total of 10 candidate QMs were submitted; 2 were rejected by the expert panel, and 5 were removed after the open comment period. The 3 approved QMs included: (1) documentation of family history of cardiomyopathy, early coronary artery disease or sudden death, (2) performance of electrocardiogram in all patients, and (3) performance of an echocardiogram to evaluate coronary arteries in patients with exertional chest pain. Despite practice variation and limited prospective data, 3 QMs were approved, with measurable data points which may be extracted from the medical record. However, further prospective studies are necessary to define practice guidelines and to develop appropriate use criteria in this population. © 2017 Wiley Periodicals, Inc.

A New Distance Metric for Unsupervised Learning of Categorical Data.

PubMed

Jia, Hong; Cheung, Yiu-Ming; Liu, Jiming

2016-05-01

Distance metric is the basis of many learning algorithms, and its effectiveness usually has a significant influence on the learning results. In general, measuring distance for numerical data is a tractable task, but it could be a nontrivial problem for categorical data sets. This paper, therefore, presents a new distance metric for categorical data based on the characteristics of categorical values. In particular, the distance between two values from one attribute measured by this metric is determined by both the frequency probabilities of these two values and the values of other attributes that have high interdependence with the calculated one. Dynamic attribute weight is further designed to adjust the contribution of each attribute-distance to the distance between the whole data objects. Promising experimental results on different real data sets have shown the effectiveness of the proposed distance metric.

A Single Conjunction Risk Assessment Metric: the F-Value

NASA Technical Reports Server (NTRS)

Frigm, Ryan Clayton; Newman, Lauri K.

2009-01-01

The Conjunction Assessment Team at NASA Goddard Space Flight Center provides conjunction risk assessment for many NASA robotic missions. These risk assessments are based on several figures of merit, such as miss distance, probability of collision, and orbit determination solution quality. However, these individual metrics do not singly capture the overall risk associated with a conjunction, making it difficult for someone without this complete understanding to take action, such as an avoidance maneuver. The goal of this analysis is to introduce a single risk index metric that can easily convey the level of risk without all of the technical details. The proposed index is called the conjunction "F-value." This paper presents the concept of the F-value and the tuning of the metric for use in routine Conjunction Assessment operations.

Is an objective refraction optimised using the visual Strehl ratio better than a subjective refraction?

PubMed

Hastings, Gareth D; Marsack, Jason D; Nguyen, Lan Chi; Cheng, Han; Applegate, Raymond A

2017-05-01

To prospectively examine whether using the visual image quality metric, visual Strehl (VSX), to optimise objective refraction from wavefront error measurements can provide equivalent or better visual performance than subjective refraction and which refraction is preferred in free viewing. Subjective refractions and wavefront aberrations were measured on 40 visually-normal eyes of 20 subjects, through natural and dilated pupils. For each eye a sphere, cylinder, and axis prescription was also objectively determined that optimised visual image quality (VSX) for the measured wavefront error. High contrast (HC) and low contrast (LC) logMAR visual acuity (VA) and short-term monocular distance vision preference were recorded and compared between the VSX-objective and subjective prescriptions both undilated and dilated. For 36 myopic eyes, clinically equivalent (and not statistically different) HC VA was provided with both the objective and subjective refractions (undilated mean ± S.D. was -0.06 ± 0.04 with both refractions; dilated was -0.05 ± 0.04 with the objective, and -0.05 ± 0.05 with the subjective refraction). LC logMAR VA provided by the objective refraction was also clinically equivalent and not statistically different to that provided by the subjective refraction through both natural and dilated pupils for myopic eyes. In free viewing the objective prescription was preferred over the subjective by 72% of myopic eyes when not dilated. For four habitually undercorrected high hyperopic eyes, the VSX-objective refraction was more positive in spherical power and VA poorer than with the subjective refraction. A method of simultaneously optimising sphere, cylinder, and axis from wavefront error measurements, using the visual image quality metric VSX, is described. In myopic subjects, visual performance, as measured by HC and LC VA, with this VSX-objective refraction was found equivalent to that provided by subjective refraction, and was typically preferred

Is an objective refraction optimised using the visual Strehl ratio better than a subjective refraction?

PubMed Central

Hastings, Gareth D.; Marsack, Jason D.; Nguyen, Lan Chi; Cheng, Han; Applegate, Raymond A.

2017-01-01

Purpose To prospectively examine whether using the visual image quality metric, visual Strehl (VSX), to optimise objective refraction from wavefront error measurements can provide equivalent or better visual performance than subjective refraction and which refraction is preferred in free viewing. Methods Subjective refractions and wavefront aberrations were measured on 40 visually-normal eyes of 20 subjects, through natural and dilated pupils. For each eye a sphere, cylinder, and axis prescription was also objectively determined that optimised visual image quality (VSX) for the measured wavefront error. High contrast (HC) and low contrast (LC) logMAR visual acuity (VA) and short-term monocular distance vision preference were recorded and compared between the VSX-objective and subjective prescriptions both undilated and dilated. Results For 36 myopic eyes, clinically equivalent (and not statistically different) HC VA was provided with both the objective and subjective refractions (undilated mean ±SD was −0.06 ±0.04 with both refractions; dilated was −0.05 ±0.04 with the objective, and −0.05 ±0.05 with the subjective refraction). LC logMAR VA provided by the objective refraction was also clinically equivalent and not statistically different to that provided by the subjective refraction through both natural and dilated pupils for myopic eyes. In free viewing the objective prescription was preferred over the subjective by 72% of myopic eyes when not dilated. For four habitually undercorrected high hyperopic eyes, the VSX-objective refraction was more positive in spherical power and VA poorer than with the subjective refraction. Conclusions A method of simultaneously optimising sphere, cylinder, and axis from wavefront error measurements, using the visual image quality metric VSX, is described. In myopic subjects, visual performance, as measured by HC and LC VA, with this VSX-objective refraction was found equivalent to that provided by subjective refraction

Disturbance metrics predict a wetland Vegetation Index of Biotic Integrity

USGS Publications Warehouse

Stapanian, Martin A.; Mack, John; Adams, Jean V.; Gara, Brian; Micacchion, Mick

2013-01-01

Indices of biological integrity of wetlands based on vascular plants (VIBIs) have been developed in many areas in the USA. Knowledge of the best predictors of VIBIs would enable management agencies to make better decisions regarding mitigation site selection and performance monitoring criteria. We use a novel statistical technique to develop predictive models for an established index of wetland vegetation integrity (Ohio VIBI), using as independent variables 20 indices and metrics of habitat quality, wetland disturbance, and buffer area land use from 149 wetlands in Ohio, USA. For emergent and forest wetlands, predictive models explained 61% and 54% of the variability, respectively, in Ohio VIBI scores. In both cases the most important predictor of Ohio VIBI score was a metric that assessed habitat alteration and development in the wetland. Of secondary importance as a predictor was a metric that assessed microtopography, interspersion, and quality of vegetation communities in the wetland. Metrics and indices assessing disturbance and land use of the buffer area were generally poor predictors of Ohio VIBI scores. Our results suggest that vegetation integrity of emergent and forest wetlands could be most directly enhanced by minimizing substrate and habitat disturbance within the wetland. Such efforts could include reducing or eliminating any practices that disturb the soil profile, such as nutrient enrichment from adjacent farm land, mowing, grazing, or cutting or removing woody plants.

QualityML: a dictionary for quality metadata encoding

NASA Astrophysics Data System (ADS)

Ninyerola, Miquel; Sevillano, Eva; Serral, Ivette; Pons, Xavier; Zabala, Alaitz; Bastin, Lucy; Masó, Joan

2014-05-01

attribute correctness) Level 2: Measurement field (e.g., DifferentialErrors1D) Level 3: Statistic or Metric (e.g., Half-lengthConfidenceInterval) Level 4: Units (e.g. Celsius degrees) Level 5: Value (e.g.0.5) Level 6: Specifications. Additional information on how the measurement took place, citation of the reference data, the traceability of the process and a publication describing the validation process encoded using new 19157 elements or the GeoViQua (http://www.geoviqua.org) Quality Model (PQM-UQM) extensions to the ISO models. Finally, keep in mind, that QualityML is not just suitable for encoding dataset level but also considers pixel and object level uncertainties. This is done by link the metadata quality descriptions with layers representing not just the data but the uncertainty values associated with each geospatial element.

Quality Measures in Stroke

PubMed Central

Poisson, Sharon N.; Josephson, S. Andrew

2011-01-01

Stroke is a major public health burden, and accounts for many hospitalizations each year. Due to gaps in practice and recommended guidelines, there has been a recent push toward implementing quality measures to be used for improving patient care, comparing institutions, as well as for rewarding or penalizing physicians through pay-for-performance. This article reviews the major organizations involved in implementing quality metrics for stroke, and the 10 major metrics currently being tracked. We also discuss possible future metrics and the implications of public reporting and using metrics for pay-for-performance. PMID:23983840

General relativity: An erfc metric

NASA Astrophysics Data System (ADS)

Plamondon, Réjean

2018-06-01

This paper proposes an erfc potential to incorporate in a symmetric metric. One key feature of this model is that it relies on the existence of an intrinsic physical constant σ, a star-specific proper length that scales all its surroundings. Based thereon, the new metric is used to study the space-time geometry of a static symmetric massive object, as seen from its interior. The analytical solutions to the Einstein equation are presented, highlighting the absence of singularities and discontinuities in such a model. The geodesics are derived in their second- and first-order differential formats. Recalling the slight impact of the new model on the classical general relativity tests in the solar system, a number of facts and open problems are briefly revisited on the basis of a heuristic definition of σ. A special attention is given to gravitational collapses and non-singular black holes.

Metric Conversion

Atmospheric Science Data Center

2013-03-12

Metric Weights and Measures The metric system is based on 10s.  For example, 10 millimeters = 1 centimeter, 10 ... Special Publications: NIST Guide to SI Units: Conversion Factors NIST Guide to SI Units: Conversion Factors listed ...

Resilience Metrics for the Electric Power System: A Performance-Based Approach.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vugrin, Eric D.; Castillo, Andrea R; Silva-Monroy, Cesar Augusto

Grid resilience is a concept related to a power system's ability to continue operating and delivering power even in the event that low probability, high-consequence disruptions such as hurricanes, earthquakes, and cyber-attacks occur. Grid resilience objectives focus on managing and, ideally, minimizing potential consequences that occur as a result of these disruptions. Currently, no formal grid resilience definitions, metrics, or analysis methods have been universally accepted. This document describes an effort to develop and describe grid resilience metrics and analysis methods. The metrics and methods described herein extend upon the Resilience Analysis Process (RAP) developed by Watson et al. formore » the 2015 Quadrennial Energy Review. The extension allows for both outputs from system models and for historical data to serve as the basis for creating grid resilience metrics and informing grid resilience planning and response decision-making. This document describes the grid resilience metrics and analysis methods. Demonstration of the metrics and methods is shown through a set of illustrative use cases.« less

Quantitative application of sigma metrics in medical biochemistry.

PubMed

Nanda, Sunil Kumar; Ray, Lopamudra

2013-12-01

Laboratory errors are result of a poorly designed quality system in the laboratory. Six Sigma is an error reduction methodology that has been successfully applied at Motorola and General Electric. Sigma (σ) is the mathematical symbol for standard deviation (SD). Sigma methodology can be applied wherever an outcome of a process has to be measured. A poor outcome is counted as an error or defect. This is quantified as defects per million (DPM). A six sigma process is one in which 99.999666% of the products manufactured are statistically expected to be free of defects. Six sigma concentrates, on regulating a process to 6 SDs, represents 3.4 DPM (defects per million) opportunities. It can be inferred that as sigma increases, the consistency and steadiness of the test improves, thereby reducing the operating costs. We aimed to gauge performance of our laboratory parameters by sigma metrics. Evaluation of sigma metrics in interpretation of parameter performance in clinical biochemistry. The six month internal QC (October 2012 to march 2013) and EQAS (external quality assurance scheme) were extracted for the parameters-Glucose, Urea, Creatinine, Total Bilirubin, Total Protein, Albumin, Uric acid, Total Cholesterol, Triglycerides, Chloride, SGOT, SGPT and ALP. Coefficient of variance (CV) were calculated from internal QC for these parameters. Percentage bias for these parameters was calculated from the EQAS. Total allowable errors were followed as per Clinical Laboratory Improvement Amendments (CLIA) guidelines. Sigma metrics were calculated from CV, percentage bias and total allowable error for the above mentioned parameters. For parameters - Total bilirubin, uric acid, SGOT, SGPT and ALP, the sigma values were found to be more than 6. For parameters - glucose, Creatinine, triglycerides, urea, the sigma values were found to be between 3 to 6. For parameters - total protein, albumin, cholesterol and chloride, the sigma values were found to be less than 3. ALP was the best

Quality of Individualised Education Programme Goals and Objectives for Preschool Children with Disabilities

ERIC Educational Resources Information Center

Rakap, Salih

2015-01-01

Individualised education programmes (IEPs) are the road maps for individualising services for children with disabilities, specifically through the development of high-quality child goals/objectives. High-quality IEP goals/objectives that are developed based on a comprehensive assessment of child functioning and directly connected to intervention…

Conceptual model of comprehensive research metrics for improved human health and environment.

PubMed

Engel-Cox, Jill A; Van Houten, Bennett; Phelps, Jerry; Rose, Shyanika W

2008-05-01

Federal, state, and private research agencies and organizations have faced increasing administrative and public demand for performance measurement. Historically, performance measurement predominantly consisted of near-term outputs measured through bibliometrics. The recent focus is on accountability for investment based on long-term outcomes. Developing measurable outcome-based metrics for research programs has been particularly challenging, because of difficulty linking research results to spatially and temporally distant outcomes. Our objective in this review is to build a logic model and associated metrics through which to measure the contribution of environmental health research programs to improvements in human health, the environment, and the economy. We used expert input and literature research on research impact assessment. With these sources, we developed a logic model that defines the components and linkages between extramural environmental health research grant programs and the outputs and outcomes related to health and social welfare, environmental quality and sustainability, economics, and quality of life. The logic model focuses on the environmental health research portfolio of the National Institute of Environmental Health Sciences (NIEHS) Division of Extramural Research and Training. The model delineates pathways for contributions by five types of institutional partners in the research process: NIEHS, other government (federal, state, and local) agencies, grantee institutions, business and industry, and community partners. The model is being applied to specific NIEHS research applications and the broader research community. We briefly discuss two examples and discuss the strengths and limits of outcome-based evaluation of research programs.

Experimental constraints on metric and non-metric theories of gravity

NASA Technical Reports Server (NTRS)

Will, Clifford M.

1989-01-01

Experimental constraints on metric and non-metric theories of gravitation are reviewed. Tests of the Einstein Equivalence Principle indicate that only metric theories of gravity are likely to be viable. Solar system experiments constrain the parameters of the weak field, post-Newtonian limit to be close to the values predicted by general relativity. Future space experiments will provide further constraints on post-Newtonian gravity.

DATA QUALITY OBJECTIVES IN RESEARCH PLANNING AT MED: THREE CASE STUDIES

EPA Science Inventory

This course will give a quality assurance perspective to research planning by describing the Data Quality Objective Process....Written plans are mandatory for all EPA environmental data collection activities according to EPA Order 5360.1 CHG 1 and Federal Acquisition Regulations,...

A perceptual metric for photo retouching.

PubMed

Kee, Eric; Farid, Hany

2011-12-13

In recent years, advertisers and magazine editors have been widely criticized for taking digital photo retouching to an extreme. Impossibly thin, tall, and wrinkle- and blemish-free models are routinely splashed onto billboards, advertisements, and magazine covers. The ubiquity of these unrealistic and highly idealized images has been linked to eating disorders and body image dissatisfaction in men, women, and children. In response, several countries have considered legislating the labeling of retouched photos. We describe a quantitative and perceptually meaningful metric of photo retouching. Photographs are rated on the degree to which they have been digitally altered by explicitly modeling and estimating geometric and photometric changes. This metric correlates well with perceptual judgments of photo retouching and can be used to objectively judge by how much a retouched photo has strayed from reality.

A method for the use of landscape metrics in freshwater research and management

USGS Publications Warehouse

Kearns, F.R.; Kelly, N.M.; Carter, J.L.; Resh, V.H.

2005-01-01

Freshwater research and management efforts could be greatly enhanced by a better understanding of the relationship between landscape-scale factors and water quality indicators. This is particularly true in urban areas, where land transformation impacts stream systems at a variety of scales. Despite advances in landscape quantification methods, several studies attempting to elucidate the relationship between land use/land cover (LULC) and water quality have resulted in mixed conclusions. However, these studies have largely relied on compositional landscape metrics. For urban and urbanizing watersheds in particular, the use of metrics that capture spatial pattern may further aid in distinguishing the effects of various urban growth patterns, as well as exploring the interplay between environmental and socioeconomic variables. However, to be truly useful for freshwater applications, pattern metrics must be optimized based on characteristic watershed properties and common water quality point sampling methods. Using a freely available LULC data set for the Santa Clara Basin, California, USA, we quantified landscape composition and configuration for subwatershed areas upstream of individual sampling sites, reducing the number of metrics based on: (1) sensitivity to changes in extent and (2) redundancy, as determined by a multivariate factor analysis. The first two factors, interpreted as (1) patch density and distribution and (2) patch shape and landscape subdivision, explained approximately 85% of the variation in the data set, and are highly reflective of the heterogeneous urban development pattern found in the study area. Although offering slightly less explanatory power, compositional metrics can provide important contextual information. ?? Springer 2005.

Double shell tanks (DST) chemistry control data quality objectives

DOE Office of Scientific and Technical Information (OSTI.GOV)

BANNING, D.L.

2001-10-09

One of the main functions of the River Protection Project is to store the Hanford Site tank waste until the Waste Treatment Plant (WTP) is ready to receive and process the waste. Waste from the older single-shell tanks is being transferred to the newer double-shell tanks (DSTs). Therefore, the integrity of the DSTs must be maintained until the waste from all tanks has been retrieved and transferred to the WTP. To help maintain the integrity of the DSTs over the life of the project, specific chemistry limits have been established to control corrosion of the DSTs. These waste chemistry limitsmore » are presented in the Technical Safety Requirements (TSR) document HNF-SD-WM-TSR-006, Sec. 5 . IS, Rev 2B (CHG 200 I). In order to control the chemistry in the DSTs, the Chemistry Control Program will require analyses of the tank waste. This document describes the Data Quality Objective (DUO) process undertaken to ensure appropriate data will be collected to control the waste chemistry in the DSTs. The DQO process was implemented in accordance with Data Quality Objectives for Sampling and Analyses, HNF-IP-0842, Rev. Ib, Vol. IV, Section 4.16, (Banning 2001) and the U.S. Environmental Protection Agency EPA QA/G4, Guidance for the Data Quality Objectives Process (EPA 1994), with some modifications to accommodate project or tank specific requirements and constraints.« less

An accurate metric for the spacetime around rotating neutron stars

NASA Astrophysics Data System (ADS)

Pappas, George

2017-04-01

The problem of having an accurate description of the spacetime around rotating neutron stars is of great astrophysical interest. For astrophysical applications, one needs to have a metric that captures all the properties of the spacetime around a rotating neutron star. Furthermore, an accurate appropriately parametrized metric, I.e. a metric that is given in terms of parameters that are directly related to the physical structure of the neutron star, could be used to solve the inverse problem, which is to infer the properties of the structure of a neutron star from astrophysical observations. In this work, we present such an approximate stationary and axisymmetric metric for the exterior of rotating neutron stars, which is constructed using the Ernst formalism and is parametrized by the relativistic multipole moments of the central object. This metric is given in terms of an expansion on the Weyl-Papapetrou coordinates with the multipole moments as free parameters and is shown to be extremely accurate in capturing the physical properties of a neutron star spacetime as they are calculated numerically in general relativity. Because the metric is given in terms of an expansion, the expressions are much simpler and easier to implement, in contrast to previous approaches. For the parametrization of the metric in general relativity, the recently discovered universal 3-hair relations are used to produce a three-parameter metric. Finally, a straightforward extension of this metric is given for scalar-tensor theories with a massless scalar field, which also admit a formulation in terms of an Ernst potential.

The SI Metric System and Practical Applications.

ERIC Educational Resources Information Center

Carney, Richard W.

Intended for use in the technical program of a technical institute or community college, this student manual is designed to provide background in the metric system contributing to employability. Nine units are presented with objectives stated for each unit followed by questions or exercises. (Printed answers are supplied when necessary.) Unit 1…

(LMRG): Microscope Resolution, Objective Quality, Spectral Accuracy and Spectral Un-mixing

PubMed Central

Bayles, Carol J.; Cole, Richard W.; Eason, Brady; Girard, Anne-Marie; Jinadasa, Tushare; Martin, Karen; McNamara, George; Opansky, Cynthia; Schulz, Katherine; Thibault, Marc; Brown, Claire M.

2012-01-01

The second study by the LMRG focuses on measuring confocal laser scanning microscope (CLSM) resolution, objective lens quality, spectral imaging accuracy and spectral un-mixing. Affordable test samples for each aspect of the study were designed, prepared and sent to 116 labs from 23 countries across the globe. Detailed protocols were designed for the three tests and customized for most of the major confocal instruments being used by the study participants. One protocol developed for measuring resolution and objective quality was recently published in Nature Protocols (Cole, R. W., T. Jinadasa, et al. (2011). Nature Protocols 6(12): 1929–1941). The first study involved 3D imaging of sub-resolution fluorescent microspheres to determine the microscope point spread function. Results of the resolution studies as well as point spread function quality (i.e. objective lens quality) from 140 different objective lenses will be presented. The second study of spectral accuracy looked at the reflection of the laser excitation lines into the spectral detection in order to determine the accuracy of these systems to report back the accurate laser emission wavelengths. Results will be presented from 42 different spectral confocal systems. Finally, samples with double orange beads (orange core and orange coating) were imaged spectrally and the imaging software was used to un-mix fluorescence signals from the two orange dyes. Results from 26 different confocal systems will be summarized. Time will be left to discuss possibilities for the next LMRG study.

Quality evaluation of motion-compensated edge artifacts in compressed video.

PubMed

Leontaris, Athanasios; Cosman, Pamela C; Reibman, Amy R

2007-04-01

Little attention has been paid to an impairment common in motion-compensated video compression: the addition of high-frequency (HF) energy as motion compensation displaces blocking artifacts off block boundaries. In this paper, we employ an energy-based approach to measure this motion-compensated edge artifact, using both compressed bitstream information and decoded pixels. We evaluate the performance of our proposed metric, along with several blocking and blurring metrics, on compressed video in two ways. First, ordinal scales are evaluated through a series of expectations that a good quality metric should satisfy: the objective evaluation. Then, the best performing metrics are subjectively evaluated. The same subjective data set is finally used to obtain interval scales to gain more insight. Experimental results show that we accurately estimate the percentage of the added HF energy in compressed video.

Specification-based software sizing: An empirical investigation of function metrics

NASA Technical Reports Server (NTRS)

Jeffery, Ross; Stathis, John

1993-01-01

For some time the software industry has espoused the need for improved specification-based software size metrics. This paper reports on a study of nineteen recently developed systems in a variety of application domains. The systems were developed by a single software services corporation using a variety of languages. The study investigated several metric characteristics. It shows that: earlier research into inter-item correlation within the overall function count is partially supported; a priori function counts, in themself, do not explain the majority of the effort variation in software development in the organization studied; documentation quality is critical to accurate function identification; and rater error is substantial in manual function counting. The implication of these findings for organizations using function based metrics are explored.

A bridge role metric model for nodes in software networks.

PubMed

Li, Bo; Feng, Yanli; Ge, Shiyu; Li, Dashe

2014-01-01

A bridge role metric model is put forward in this paper. Compared with previous metric models, our solution of a large-scale object-oriented software system as a complex network is inherently more realistic. To acquire nodes and links in an undirected network, a new model that presents the crucial connectivity of a module or the hub instead of only centrality as in previous metric models is presented. Two previous metric models are described for comparison. In addition, it is obvious that the fitting curve between the Bre results and degrees can well be fitted by a power law. The model represents many realistic characteristics of actual software structures, and a hydropower simulation system is taken as an example. This paper makes additional contributions to an accurate understanding of module design of software systems and is expected to be beneficial to software engineering practices.

A Bridge Role Metric Model for Nodes in Software Networks

PubMed Central

Li, Bo; Feng, Yanli; Ge, Shiyu; Li, Dashe

2014-01-01

A bridge role metric model is put forward in this paper. Compared with previous metric models, our solution of a large-scale object-oriented software system as a complex network is inherently more realistic. To acquire nodes and links in an undirected network, a new model that presents the crucial connectivity of a module or the hub instead of only centrality as in previous metric models is presented. Two previous metric models are described for comparison. In addition, it is obvious that the fitting curve between the results and degrees can well be fitted by a power law. The model represents many realistic characteristics of actual software structures, and a hydropower simulation system is taken as an example. This paper makes additional contributions to an accurate understanding of module design of software systems and is expected to be beneficial to software engineering practices. PMID:25364938

Properties of C-metric spaces

NASA Astrophysics Data System (ADS)

Croitoru, Anca; Apreutesei, Gabriela; Mastorakis, Nikos E.

2017-09-01

The subject of this paper belongs to the theory of approximate metrics [23]. An approximate metric on X is a real application defined on X × X that satisfies only a part of the metric axioms. In a recent paper [23], we introduced a new type of approximate metric, named C-metric, that is an application which satisfies only two metric axioms: symmetry and triangular inequality. The remarkable fact in a C-metric space is that a topological structure induced by the C-metric can be defined. The innovative idea of this paper is that we obtain some convergence properties of a C-metric space in the absence of a metric. In this paper we investigate C-metric spaces. The paper is divided into four sections. Section 1 is for Introduction. In Section 2 we recall some concepts and preliminary results. In Section 3 we present some properties of C-metric spaces, such as convergence properties, a canonical decomposition and a C-fixed point theorem. Finally, in Section 4 some conclusions are highlighted.

About Using the Metric System.

ERIC Educational Resources Information Center

Illinois State Office of Education, Springfield.

This booklet contains a brief introduction to the use of the metric system. Topics covered include: (1) what is the metric system; (2) how to think metric; (3) some advantages of the metric system; (4) basics of the metric system; (5) how to measure length, area, volume, mass and temperature the metric way; (6) some simple calculations using…

Metrics for Radiologists in the Era of Value-based Health Care Delivery.

PubMed

Sarwar, Ammar; Boland, Giles; Monks, Annamarie; Kruskal, Jonathan B

2015-01-01

Accelerated by the Patient Protection and Affordable Care Act of 2010, health care delivery in the United States is poised to move from a model that rewards the volume of services provided to one that rewards the value provided by such services. Radiology department operations are currently managed by an array of metrics that assess various departmental missions, but many of these metrics do not measure value. Regulators and other stakeholders also influence what metrics are used to assess medical imaging. Metrics such as the Physician Quality Reporting System are increasingly being linked to financial penalties. In addition, metrics assessing radiology's contribution to cost or outcomes are currently lacking. In fact, radiology is widely viewed as a contributor to health care costs without an adequate understanding of its contribution to downstream cost savings or improvement in patient outcomes. The new value-based system of health care delivery and reimbursement will measure a provider's contribution to reducing costs and improving patient outcomes with the intention of making reimbursement commensurate with adherence to these metrics. The authors describe existing metrics and their application to the practice of radiology, discuss the so-called value equation, and suggest possible metrics that will be useful for demonstrating the value of radiologists' services to their patients. (©)RSNA, 2015.

A Control Law Design Method Facilitating Control Power, Robustness, Agility, and Flying Qualities Tradeoffs: CRAFT

NASA Technical Reports Server (NTRS)

Murphy, Patrick C.; Davidson, John B.

1998-01-01

A multi-input, multi-output control law design methodology, named "CRAFT", is presented. CRAFT stands for the design objectives addressed, namely, Control power, Robustness, Agility, and Flying Qualities Tradeoffs. The methodology makes use of control law design metrics from each of the four design objective areas. It combines eigenspace assignment, which allows for direct specification of eigenvalues and eigenvectors, with a graphical approach for representing the metrics that captures numerous design goals in one composite illustration. Sensitivity of the metrics to eigenspace choice is clearly displayed, enabling the designer to assess the cost of design tradeoffs. This approach enhances the designer's ability to make informed design tradeoffs and to reach effective final designs. An example of the CRAFT methodology applied to an advanced experimental fighter and discussion of associated design issues are provided.

DATA QUALITY OBJECTIVES-FOUNDATION OF A SUCCESSFUL MONITORING PROGRAM

EPA Science Inventory

The data quality objectives (DQO) process is a fundamental site characterization tool and the foundation of a successful monitoring program. The DQO process is a systematic planning approach based on the scientific method of inquiry. The process identifies the goals of data col...

The effect of surgeon and hospital volume on shoulder arthroplasty perioperative quality metrics.

PubMed

Singh, Anshu; Yian, Edward H; Dillon, Mark T; Takayanagi, Miwa; Burke, Mary F; Navarro, Ronald A

2014-08-01

There has been a significant increase in both the incidence of shoulder arthroplasty and the number of surgeons performing these procedures. Literature regarding the relationship between surgeon or hospital volume and the performance of modern shoulder arthroplasty is limited. This study examines the effect of surgeon or hospital shoulder arthroplasty volume on perioperative metrics related to shoulder hemiarthroplasty, total shoulder arthroplasty, and reverse shoulder arthroplasty. Blood loss, length of stay, and operative time were the main endpoints analyzed. Prospective data were analyzed from a multicenter shoulder arthroplasty registry; 1176 primary shoulder arthroplasty cases were analyzed. Correlation and analysis of covariance were used to examine the association between surgeon and hospital volume and perioperative metrics adjusting for age, sex, and body mass index. Surgeon volume is inversely correlated with length of stay for hemiarthroplasty and total shoulder arthroplasty and with blood loss and operative time for all 3 procedures. Hospital volume is inversely correlated with length of stay for hemiarthroplasty, with blood loss for total and reverse shoulder arthroplasty, and with operative time for all 3 procedures. High-volume surgeons performed shoulder arthroplasty 30 to 50 minutes faster than low-volume surgeons did. Higher surgeon and hospital case volumes led to improved perioperative metrics with all shoulder arthroplasty procedures, including reverse total shoulder arthroplasty, which has not been previously described in the literature. Surgeon volume had a larger effect on metrics than hospital volume did. This study supports the concept that complex shoulder procedures are, on average, performed more efficiently by higher volume surgeons in higher volume centers. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Driving photomask supplier quality through automation

NASA Astrophysics Data System (ADS)

Russell, Drew; Espenscheid, Andrew

2007-10-01

In 2005, Freescale Semiconductor's newly centralized mask data prep organization (MSO) initiated a project to develop an automated global quality validation system for photomasks delivered to Freescale Semiconductor fabs. The system handles Certificate of Conformance (CofC) quality metric collection, validation, reporting and an alert system for all photomasks shipped to Freescale fabs from all qualified global suppliers. The completed system automatically collects 30+ quality metrics for each photomask shipped. Other quality metrics are generated from the collected data and quality metric conformance is automatically validated to specifications or control limits with failure alerts emailed to fab photomask and mask data prep engineering. A quality data warehouse stores the data for future analysis, which is performed quarterly. The improved access to data provided by the system has improved Freescale engineers' ability to spot trends and opportunities for improvement with our suppliers' processes. This paper will review each phase of the project, current system capabilities and quality system benefits for both our photomask suppliers and Freescale.

Performance Metrics for Liquid Chromatography-Tandem Mass Spectrometry Systems in Proteomics Analyses*

PubMed Central

Rudnick, Paul A.; Clauser, Karl R.; Kilpatrick, Lisa E.; Tchekhovskoi, Dmitrii V.; Neta, Pedatsur; Blonder, Nikša; Billheimer, Dean D.; Blackman, Ronald K.; Bunk, David M.; Cardasis, Helene L.; Ham, Amy-Joan L.; Jaffe, Jacob D.; Kinsinger, Christopher R.; Mesri, Mehdi; Neubert, Thomas A.; Schilling, Birgit; Tabb, David L.; Tegeler, Tony J.; Vega-Montoto, Lorenzo; Variyath, Asokan Mulayath; Wang, Mu; Wang, Pei; Whiteaker, Jeffrey R.; Zimmerman, Lisa J.; Carr, Steven A.; Fisher, Susan J.; Gibson, Bradford W.; Paulovich, Amanda G.; Regnier, Fred E.; Rodriguez, Henry; Spiegelman, Cliff; Tempst, Paul; Liebler, Daniel C.; Stein, Stephen E.

2010-01-01

A major unmet need in LC-MS/MS-based proteomics analyses is a set of tools for quantitative assessment of system performance and evaluation of technical variability. Here we describe 46 system performance metrics for monitoring chromatographic performance, electrospray source stability, MS1 and MS2 signals, dynamic sampling of ions for MS/MS, and peptide identification. Applied to data sets from replicate LC-MS/MS analyses, these metrics displayed consistent, reasonable responses to controlled perturbations. The metrics typically displayed variations less than 10% and thus can reveal even subtle differences in performance of system components. Analyses of data from interlaboratory studies conducted under a common standard operating procedure identified outlier data and provided clues to specific causes. Moreover, interlaboratory variation reflected by the metrics indicates which system components vary the most between laboratories. Application of these metrics enables rational, quantitative quality assessment for proteomics and other LC-MS/MS analytical applications. PMID:19837981

Automated Assessment of Visual Quality of Digital Video

NASA Technical Reports Server (NTRS)

Watson, Andrew B.; Ellis, Stephen R. (Technical Monitor)

1997-01-01

The advent of widespread distribution of digital video creates a need for automated methods for evaluating visual quality of digital video. This is particularly so since most digital video is compressed using lossy methods, which involve the controlled introduction of potentially visible artifacts. Compounding the problem is the bursty nature of digital video, which requires adaptive bit allocation based on visual quality metrics. In previous work, we have developed visual quality metrics for evaluating, controlling, and optimizing the quality of compressed still images[1-4]. These metrics incorporate simplified models of human visual sensitivity to spatial and chromatic visual signals. The challenge of video quality metrics is to extend these simplified models to temporal signals as well. In this presentation I will discuss a number of the issues that must be resolved in the design of effective video quality metrics. Among these are spatial, temporal, and chromatic sensitivity and their interactions, visual masking, and implementation complexity. I will also touch on the question of how to evaluate the performance of these metrics.

Hearing a Melody in Different Ways: Multistability of Metrical Interpretation, Reflected in Rate Limits of Sensorimotor Synchronization

ERIC Educational Resources Information Center

Repp, Bruno H.

2007-01-01

Music commonly induces the feeling of a regular beat (i.e., a metrical structure) in listeners. However, musicians can also intentionally impose a beat (i.e., a metrical interpretation) on a metrically ambiguous passage. The present study aimed to provide objective evidence for this little-studied mental ability. Participants were prompted with…

Application of a simple, affordable quality metric tool to colorectal, upper gastrointestinal, hernia, and hepatobiliary surgery patients: the HARM score.

PubMed

Brady, Justin T; Ko, Bona; Hohmann, Samuel F; Crawshaw, Benjamin P; Leinicke, Jennifer A; Steele, Scott R; Augestad, Knut M; Delaney, Conor P

2018-06-01

Quality is the major driver for both clinical and financial assessment. There remains a need for simple, affordable, quality metric tools to evaluate patient outcomes, which led us to develop the HospitAl length of stay, Readmission and Mortality (HARM) score. We hypothesized that the HARM score would be a reliable tool to assess patient outcomes across various surgical specialties. From 2011 to 2015, we identified colorectal, hepatobiliary, upper gastrointestinal, and hernia surgery admissions using the Vizient Clinical Database. Individual and hospital HARM scores were calculated from length of stay, 30-day readmission, and mortality rates. We evaluated the correlation of HARM scores with complication rates using the Clavien-Dindo classification. We identified 525,083 surgical patients: 206,981 colorectal, 164,691 hepatobiliary, 97,157 hernia, and 56,254 upper gastrointestinal. Overall, 53.8% of patients were admitted electively with a mean HARM score of 2.24; 46.2% were admitted emergently with a mean HARM score of 1.45 (p < 0.0001). All HARM components correlated with patient complications on logistic regression (p < 0.0001). The mean length of stay increased from 3.2 ± 1.8 days for a HARM score < 2 to 15.1 ± 12.2 days for a HARM score > 4 (p < 0.001). In elective admissions, for HARM categories of < 2, 2-< 3, 3-4, and > 4, complication rates were 9.3, 23.2, 38.8, and 71.6%, respectively. There was a similar trend for increasing HARM score in emergent admissions as well. For all surgical procedure categories, increasing HARM score, with and without risk adjustment, correlated with increasing severity of complications by Clavien-Dindo classification. The HARM score is an easy-to-use quality metric that correlates with increasing complication rates and complication severity across multiple surgical disciplines when evaluated on a large administrative database. This inexpensive tool could be adopted across multiple institutions

Metrics for Evaluating the Accuracy of Solar Power Forecasting: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, J.; Hodge, B. M.; Florita, A.

2013-10-01

Forecasting solar energy generation is a challenging task due to the variety of solar power systems and weather regimes encountered. Forecast inaccuracies can result in substantial economic losses and power system reliability issues. This paper presents a suite of generally applicable and value-based metrics for solar forecasting for a comprehensive set of scenarios (i.e., different time horizons, geographic locations, applications, etc.). In addition, a comprehensive framework is developed to analyze the sensitivity of the proposed metrics to three types of solar forecasting improvements using a design of experiments methodology, in conjunction with response surface and sensitivity analysis methods. The resultsmore » show that the developed metrics can efficiently evaluate the quality of solar forecasts, and assess the economic and reliability impact of improved solar forecasting.« less

Assessing precision, bias and sigma-metrics of 53 measurands of the Alinity ci system.

PubMed

Westgard, Sten; Petrides, Victoria; Schneider, Sharon; Berman, Marvin; Herzogenrath, Jörg; Orzechowski, Anthony

2017-12-01

Assay performance is dependent on the accuracy and precision of a given method. These attributes can be combined into an analytical Sigma-metric, providing a simple value for laboratorians to use in evaluating a test method's capability to meet its analytical quality requirements. Sigma-metrics were determined for 37 clinical chemistry assays, 13 immunoassays, and 3 ICT methods on the Alinity ci system. Analytical Performance Specifications were defined for the assays, following a rationale of using CLIA goals first, then Ricos Desirable goals when CLIA did not regulate the method, and then other sources if the Ricos Desirable goal was unrealistic. A precision study was conducted at Abbott on each assay using the Alinity ci system following the CLSI EP05-A2 protocol. Bias was estimated following the CLSI EP09-A3 protocol using samples with concentrations spanning the assay's measuring interval tested in duplicate on the Alinity ci system and ARCHITECT c8000 and i2000 SR systems, where testing was also performed at Abbott. Using the regression model, the %bias was estimated at an important medical decisions point. Then the Sigma-metric was estimated for each assay and was plotted on a method decision chart. The Sigma-metric was calculated using the equation: Sigma-metric=(%TEa-|%bias|)/%CV. The Sigma-metrics and Normalized Method Decision charts demonstrate that a majority of the Alinity assays perform at least at five Sigma or higher, at or near critical medical decision levels. More than 90% of the assays performed at Five and Six Sigma. None performed below Three Sigma. Sigma-metrics plotted on Normalized Method Decision charts provide useful evaluations of performance. The majority of Alinity ci system assays had sigma values >5 and thus laboratories can expect excellent or world class performance. Laboratorians can use these tools as aids in choosing high-quality products, further contributing to the delivery of excellent quality healthcare for patients

The Metric System--An Overview.

ERIC Educational Resources Information Center

Hovey, Larry; Hovey, Kathi

1983-01-01

Sections look at: (1) Historical Perspective; (2) Naming the New System; (3) The Metric Units; (4) Measuring Larger and Smaller Amounts; (5) Advantage of Using the Metric System; (6) Metric Symbols; (7) Conversion from Metric to Customary System; (8) General Hints for Helping Children Understand; and (9) Current Status of Metric Conversion. (MP)

Limitations of using same-hospital readmission metrics.

PubMed

Davies, Sheryl M; Saynina, Olga; McDonald, Kathryn M; Baker, Laurence C

2013-12-01

To quantify the limitations associated with restricting readmission metrics to same-hospital only readmission. Using 2000-2009 California Office of Statewide Health Planning and Development Patient Discharge Data Nonpublic file, we identified the proportion of 7-, 15- and 30-day readmissions occurring to the same hospital as the initial admission using All-cause Readmission (ACR) and 3M Corporation Potentially Preventable Readmissions (PPR) Metric. We examined the correlation between performance using same and different hospital readmission, the percent of hospitals remaining in the extreme deciles when utilizing different metrics, agreement in identifying outliers and differences in longitudinal performance. Using logistic regression, we examined the factors associated with admission to the same hospital. 68% of 30-day ACR and 70% of 30-day PPR occurred to the same hospital. Abdominopelvic procedures had higher proportions of same-hospital readmissions (87.4-88.9%), cardiac surgery had lower (72.5-74.9%) and medical DRGs were lower than surgical DRGs (67.1 vs. 71.1%). Correlation and agreement in identifying high- and low-performing hospitals was weak to moderate, except for 7-day metrics where agreement was stronger (r = 0.23-0.80, Kappa = 0.38-0.76). Agreement for within-hospital significant (P < 0.05) longitudinal change was weak (Kappa = 0.05-0.11). Beyond all patient refined-diagnostic related groups, payer was the most predictive factor with Medicare and MediCal patients having a higher likelihood of same-hospital readmission (OR 1.62, 1.73). Same-hospital readmission metrics are limited for all tested applications. Caution should be used when conducting research, quality improvement or comparative applications that do not account for readmissions to other hospitals.

Observable traces of non-metricity: New constraints on metric-affine gravity

NASA Astrophysics Data System (ADS)

Delhom-Latorre, Adrià; Olmo, Gonzalo J.; Ronco, Michele

2018-05-01

Relaxing the Riemannian condition to incorporate geometric quantities such as torsion and non-metricity may allow to explore new physics associated with defects in a hypothetical space-time microstructure. Here we show that non-metricity produces observable effects in quantum fields in the form of 4-fermion contact interactions, thereby allowing us to constrain the scale of non-metricity to be greater than 1 TeV by using results on Bahbah scattering. Our analysis is carried out in the framework of a wide class of theories of gravity in the metric-affine approach. The bound obtained represents an improvement of several orders of magnitude to previous experimental constraints.

Design and Implementation of Performance Metrics for Evaluation of Assessments Data

ERIC Educational Resources Information Center

Ahmed, Irfan; Bhatti, Arif

2016-01-01

Evocative evaluation of assessment data is essential to quantify the achievements at course and program levels. The objective of this paper is to design performance metrics and respective formulas to quantitatively evaluate the achievement of set objectives and expected outcomes at the course levels for program accreditation. Even though…

Human Performance Optimization Metrics: Consensus Findings, Gaps, and Recommendations for Future Research.

PubMed

Nindl, Bradley C; Jaffin, Dianna P; Dretsch, Michael N; Cheuvront, Samuel N; Wesensten, Nancy J; Kent, Michael L; Grunberg, Neil E; Pierce, Joseph R; Barry, Erin S; Scott, Jonathan M; Young, Andrew J; OʼConnor, Francis G; Deuster, Patricia A

2015-11-01

Human performance optimization (HPO) is defined as "the process of applying knowledge, skills and emerging technologies to improve and preserve the capabilities of military members, and organizations to execute essential tasks." The lack of consensus for operationally relevant and standardized metrics that meet joint military requirements has been identified as the single most important gap for research and application of HPO. In 2013, the Consortium for Health and Military Performance hosted a meeting to develop a toolkit of standardized HPO metrics for use in military and civilian research, and potentially for field applications by commanders, units, and organizations. Performance was considered from a holistic perspective as being influenced by various behaviors and barriers. To accomplish the goal of developing a standardized toolkit, key metrics were identified and evaluated across a spectrum of domains that contribute to HPO: physical performance, nutritional status, psychological status, cognitive performance, environmental challenges, sleep, and pain. These domains were chosen based on relevant data with regard to performance enhancers and degraders. The specific objectives at this meeting were to (a) identify and evaluate current metrics for assessing human performance within selected domains; (b) prioritize metrics within each domain to establish a human performance assessment toolkit; and (c) identify scientific gaps and the needed research to more effectively assess human performance across domains. This article provides of a summary of 150 total HPO metrics across multiple domains that can be used as a starting point-the beginning of an HPO toolkit: physical fitness (29 metrics), nutrition (24 metrics), psychological status (36 metrics), cognitive performance (35 metrics), environment (12 metrics), sleep (9 metrics), and pain (5 metrics). These metrics can be particularly valuable as the military emphasizes a renewed interest in Human Dimension efforts

Building a Patient-Reported Outcome Metric Database: One Hospital's Experience.

PubMed

Rana, Adam J

2016-06-01

A number of provisions exist within the Patient Protection and Affordable Care Act that focus on improving the delivery of health care in the United States, including quality of care. From a total joint arthroplasty perspective, the issue of quality increasingly refers to quantifying patient-reported outcome metrics (PROMs). This article describes one hospital's experience in building and maintaining an electronic PROM database for a practice of 6 board-certified orthopedic surgeons. The surgeons advocated to and worked with the hospital to contract with a joint registry database company and hire a research assistant. They implemented a standardized process for all surgical patients to fill out patient-reported outcome questionnaires at designated intervals. To date, the group has collected patient-reported outcome metric data for >4500 cases. The data are frequently used in different venues at the hospital including orthopedic quality metric and research meetings. In addition, the results were used to develop an annual outcome report. The annual report is given to patients and primary care providers, and portions of it are being used in discussions with insurance carriers. Building an electronic database to collect PROMs is a group undertaking and requires a physician champion. A considerable amount of work needs to be done up front to make its introduction a success. Once established, a PROM database can provide a significant amount of information and data that can be effectively used in multiple capacities. Copyright © 2016 Elsevier Inc. All rights reserved.

On local search for bi-objective knapsack problems.

PubMed

Liefooghe, Arnaud; Paquete, Luís; Figueira, José Rui

2013-01-01

In this article, a local search approach is proposed for three variants of the bi-objective binary knapsack problem, with the aim of maximizing the total profit and minimizing the total weight. First, an experimental study on a given structural property of connectedness of the efficient set is conducted. Based on this property, a local search algorithm is proposed and its performance is compared to exact algorithms in terms of runtime and quality metrics. The experimental results indicate that this simple local search algorithm is able to find a representative set of optimal solutions in most of the cases, and in much less time than exact algorithms.

Low-cost oblique illumination: an image quality assessment.

PubMed

Ruiz-Santaquiteria, Jesus; Espinosa-Aranda, Jose Luis; Deniz, Oscar; Sanchez, Carlos; Borrego-Ramos, Maria; Blanco, Saul; Cristobal, Gabriel; Bueno, Gloria

2018-01-01

We study the effectiveness of several low-cost oblique illumination filters to improve overall image quality, in comparison with standard bright field imaging. For this purpose, a dataset composed of 3360 diatom images belonging to 21 taxa was acquired. Subjective and objective image quality assessments were done. The subjective evaluation was performed by a group of diatom experts by psychophysical test where resolution, focus, and contrast were assessed. Moreover, some objective nonreference image quality metrics were applied to the same image dataset to complete the study, together with the calculation of several texture features to analyze the effect of these filters in terms of textural properties. Both image quality evaluation methods, subjective and objective, showed better results for images acquired using these illumination filters in comparison with the no filtered image. These promising results confirm that this kind of illumination filters can be a practical way to improve the image quality, thanks to the simple and low cost of the design and manufacturing process. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

The Albuquerque Seismological Laboratory Data Quality Analyzer

NASA Astrophysics Data System (ADS)

Ringler, A. T.; Hagerty, M.; Holland, J.; Gee, L. S.; Wilson, D.

2013-12-01

The U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL) has several efforts underway to improve data quality at its stations. The Data Quality Analyzer (DQA) is one such development. The DQA is designed to characterize station data quality in a quantitative and automated manner. Station quality is based on the evaluation of various metrics, such as timing quality, noise levels, sensor coherence, and so on. These metrics are aggregated into a measurable grade for each station. The DQA consists of a website, a metric calculator (Seedscan), and a PostgreSQL database. The website allows the user to make requests for various time periods, review specific networks and stations, adjust weighting of the station's grade, and plot metrics as a function of time. The website dynamically loads all station data from a PostgreSQL database. The database is central to the application; it acts as a hub where metric values and limited station descriptions are stored. Data is stored at the level of one sensor's channel per day. The database is populated by Seedscan. Seedscan reads and processes miniSEED data, to generate metric values. Seedscan, written in Java, compares hashes of metadata and data to detect changes and perform subsequent recalculations. This ensures that the metric values are up to date and accurate. Seedscan can be run in a scheduled task or on demand by way of a config file. It will compute metrics specified in its configuration file. While many metrics are currently in development, some are completed and being actively used. These include: availability, timing quality, gap count, deviation from the New Low Noise Model, deviation from a station's noise baseline, inter-sensor coherence, and data-synthetic fits. In all, 20 metrics are planned, but any number could be added. ASL is actively using the DQA on a daily basis for station diagnostics and evaluation. As Seedscan is scheduled to run every night, data quality analysts are able to then use the

NASA metrication activities

NASA Technical Reports Server (NTRS)

Vlannes, P. N.

1978-01-01

NASA's organization and policy for metrification, history from 1964, NASA participation in Federal agency activities, interaction with nongovernmental metrication organizations, and the proposed metrication assessment study are reviewed.

Orientation estimation of anatomical structures in medical images for object recognition

NASA Astrophysics Data System (ADS)

Bağci, Ulaş; Udupa, Jayaram K.; Chen, Xinjian

2011-03-01

Recognition of anatomical structures is an important step in model based medical image segmentation. It provides pose estimation of objects and information about "where" roughly the objects are in the image and distinguishing them from other object-like entities. In,1 we presented a general method of model-based multi-object recognition to assist in segmentation (delineation) tasks. It exploits the pose relationship that can be encoded, via the concept of ball scale (b-scale), between the binary training objects and their associated grey images. The goal was to place the model, in a single shot, close to the right pose (position, orientation, and scale) in a given image so that the model boundaries fall in the close vicinity of object boundaries in the image. Unlike position and scale parameters, we observe that orientation parameters require more attention when estimating the pose of the model as even small differences in orientation parameters can lead to inappropriate recognition. Motivated from the non-Euclidean nature of the pose information, we propose in this paper the use of non-Euclidean metrics to estimate orientation of the anatomical structures for more accurate recognition and segmentation. We statistically analyze and evaluate the following metrics for orientation estimation: Euclidean, Log-Euclidean, Root-Euclidean, Procrustes Size-and-Shape, and mean Hermitian metrics. The results show that mean Hermitian and Cholesky decomposition metrics provide more accurate orientation estimates than other Euclidean and non-Euclidean metrics.

Objective Video Quality Assessment Based on Machine Learning for Underwater Scientific Applications

PubMed Central

Moreno-Roldán, José-Miguel; Luque-Nieto, Miguel-Ángel; Poncela, Javier; Otero, Pablo

2017-01-01

Video services are meant to be a fundamental tool in the development of oceanic research. The current technology for underwater networks (UWNs) imposes strong constraints in the transmission capacity since only a severely limited bitrate is available. However, previous studies have shown that the quality of experience (QoE) is enough for ocean scientists to consider the service useful, although the perceived quality can change significantly for small ranges of variation of video parameters. In this context, objective video quality assessment (VQA) methods become essential in network planning and real time quality adaptation fields. This paper presents two specialized models for objective VQA, designed to match the special requirements of UWNs. The models are built upon machine learning techniques and trained with actual user data gathered from subjective tests. Our performance analysis shows how both of them can successfully estimate quality as a mean opinion score (MOS) value and, for the second model, even compute a distribution function for user scores. PMID:28333123

SU-G-BRB-16: Vulnerabilities in the Gamma Metric

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neal, B; Siebers, J

Purpose: To explore vulnerabilities in the gamma index metric that undermine its wide use as a radiation therapy quality assurance tool. Methods: 2D test field pairs (images) are created specifically to achieve high gamma passing rates, but to also include gross errors by exploiting the distance-to-agreement and percent-passing components of the metric. The first set has no requirement of clinical practicality, but is intended to expose vulnerabilities. The second set exposes clinically realistic vulnerabilities. To circumvent limitations inherent to user-specific tuning of prediction algorithms to match measurements, digital test cases are manually constructed, thereby mimicking high-quality image prediction. Results: Withmore » a 3 mm distance-to-agreement metric, changing field size by ±6 mm results in a gamma passing rate over 99%. For a uniform field, a lattice of passing points spaced 5 mm apart results in a passing rate of 100%. Exploiting the percent-passing component, a 10×10 cm{sup 2} field can have a 95% passing rate when an 8 cm{sup 2}=2.8×2.8 cm{sup 2} highly out-of-tolerance (e.g. zero dose) square is missing from the comparison image. For clinically realistic vulnerabilities, an arc plan for which a 2D image is created can have a >95% passing rate solely due to agreement in the lateral spillage, with the failing 5% in the critical target region. A field with an integrated boost (e.g whole brain plus small metastases) could neglect the metastases entirely, yet still pass with a 95% threshold. All the failure modes described would be visually apparent on a gamma-map image. Conclusion: The %gamma<1 metric has significant vulnerabilities. High passing rates can obscure critical faults in hypothetical and delivered radiation doses. Great caution should be used with gamma as a QA metric; users should inspect the gamma-map. Visual analysis of gamma-maps may be impractical for cine acquisition.« less

Statistical estimation of ozone exposure metrics

NASA Astrophysics Data System (ADS)

Blankenship, Erin E.; Stefanski, L. A.

Data from recent experiments at North Carolina State University and other locations provide a unique opportunity to study the effect of ambient ozone on the growth of clover. The data consist of hourly ozone measurements over a 140 day growing season at eight sites in the US, coupled with clover growth response data measured every 28 days. The objective is to model an indicator of clover growth as a function of ozone exposure. A common strategy for dealing with the numerous hourly ozone measurements is to reduce these to a single summary measurement, a so-called exposure metric, for the growth period of interest. However, the mean ozone value is not necessarily the best summarization, as it is widely believed that low levels of ozone have a negligible effect on growth, whereas peak ozone values are deleterious to plant growth. There are also suspected interactions with available sunlight, temperature and humidity. A number of exposure metrics have been proposed that reflect these beliefs by assigning different weights to ozone values according to magnitude, time of day, temperature and humidity. These weighting schemes generally depend on parameters that have, to date, been subjectively determined. We propose a statistical approach based on profile likelihoods to estimate the parameters in these exposure metrics.

Mastering Metrics

ERIC Educational Resources Information Center

Parrot, Annette M.

2005-01-01

By the time students reach a middle school science course, they are expected to make measurements using the metric system. However, most are not practiced in its use, as their experience in metrics is often limited to one unit they were taught in elementary school. This lack of knowledge is not wholly the fault of formal education. Although the…

Distance Between Sets as an Objective Measure of Retrieval Effectiveness

ERIC Educational Resources Information Center

Heine, M. H.

1973-01-01

The Marczewski-Steinhaus metric provides what appears to be an objective general measure of retrieval effectiveness within the framework of set theory and the theory of metric spaces. (19 references) (Author/SJ)

Fault Management Metrics

NASA Technical Reports Server (NTRS)

Johnson, Stephen B.; Ghoshal, Sudipto; Haste, Deepak; Moore, Craig

2017-01-01

This paper describes the theory and considerations in the application of metrics to measure the effectiveness of fault management. Fault management refers here to the operational aspect of system health management, and as such is considered as a meta-control loop that operates to preserve or maximize the system's ability to achieve its goals in the face of current or prospective failure. As a suite of control loops, the metrics to estimate and measure the effectiveness of fault management are similar to those of classical control loops in being divided into two major classes: state estimation, and state control. State estimation metrics can be classified into lower-level subdivisions for detection coverage, detection effectiveness, fault isolation and fault identification (diagnostics), and failure prognosis. State control metrics can be classified into response determination effectiveness and response effectiveness. These metrics are applied to each and every fault management control loop in the system, for each failure to which they apply, and probabilistically summed to determine the effectiveness of these fault management control loops to preserve the relevant system goals that they are intended to protect.

Manipulation of Unknown Objects to Improve the Grasp Quality Using Tactile Information.

PubMed

Montaño, Andrés; Suárez, Raúl

2018-05-03

This work presents a novel and simple approach in the area of manipulation of unknown objects considering both geometric and mechanical constraints of the robotic hand. Starting with an initial blind grasp, our method improves the grasp quality through manipulation considering the three common goals of the manipulation process: improving the hand configuration, the grasp quality and the object positioning, and, at the same time, prevents the object from falling. Tactile feedback is used to obtain local information of the contacts between the fingertips and the object, and no additional exteroceptive feedback sources are considered in the approach. The main novelty of this work lies in the fact that the grasp optimization is performed on-line as a reactive procedure using the tactile and kinematic information obtained during the manipulation. Experimental results are shown to illustrate the efficiency of the approach.

Metric Evaluation Pipeline for 3d Modeling of Urban Scenes

NASA Astrophysics Data System (ADS)

Bosch, M.; Leichtman, A.; Chilcott, D.; Goldberg, H.; Brown, M.

2017-05-01

Publicly available benchmark data and metric evaluation approaches have been instrumental in enabling research to advance state of the art methods for remote sensing applications in urban 3D modeling. Most publicly available benchmark datasets have consisted of high resolution airborne imagery and lidar suitable for 3D modeling on a relatively modest scale. To enable research in larger scale 3D mapping, we have recently released a public benchmark dataset with multi-view commercial satellite imagery and metrics to compare 3D point clouds with lidar ground truth. We now define a more complete metric evaluation pipeline developed as publicly available open source software to assess semantically labeled 3D models of complex urban scenes derived from multi-view commercial satellite imagery. Evaluation metrics in our pipeline include horizontal and vertical accuracy and completeness, volumetric completeness and correctness, perceptual quality, and model simplicity. Sources of ground truth include airborne lidar and overhead imagery, and we demonstrate a semi-automated process for producing accurate ground truth shape files to characterize building footprints. We validate our current metric evaluation pipeline using 3D models produced using open source multi-view stereo methods. Data and software is made publicly available to enable further research and planned benchmarking activities.

The Universal Plausibility Metric (UPM) & Principle (UPP).

PubMed

Abel, David L

2009-12-03

Mere possibility is not an adequate basis for asserting scientific plausibility. A precisely defined universal bound is needed beyond which the assertion of plausibility, particularly in life-origin models, can be considered operationally falsified. But can something so seemingly relative and subjective as plausibility ever be quantified? Amazingly, the answer is, "Yes." A method of objectively measuring the plausibility of any chance hypothesis (The Universal Plausibility Metric [UPM]) is presented. A numerical inequality is also provided whereby any chance hypothesis can be definitively falsified when its UPM metric of xi is < 1 (The Universal Plausibility Principle [UPP]). Both UPM and UPP pre-exist and are independent of any experimental design and data set. No low-probability hypothetical plausibility assertion should survive peer-review without subjection to the UPP inequality standard of formal falsification (xi < 1).

Double metric, generalized metric, and α' -deformed double field theory

NASA Astrophysics Data System (ADS)

Hohm, Olaf; Zwiebach, Barton

2016-03-01

We relate the unconstrained "double metric" of the "α' -geometry" formulation of double field theory to the constrained generalized metric encoding the spacetime metric and b -field. This is achieved by integrating out auxiliary field components of the double metric in an iterative procedure that induces an infinite number of higher-derivative corrections. As an application, we prove that, to first order in α' and to all orders in fields, the deformed gauge transformations are Green-Schwarz-deformed diffeomorphisms. We also prove that to first order in α' the spacetime action encodes precisely the Green-Schwarz deformation with Chern-Simons forms based on the torsionless gravitational connection. This seems to be in tension with suggestions in the literature that T-duality requires a torsionful connection, but we explain that these assertions are ambiguous since actions that use different connections are related by field redefinitions.

A family of metric gravities

NASA Astrophysics Data System (ADS)

Shuler, Robert

2018-04-01

The goal of this paper is to take a completely fresh approach to metric gravity, in which the metric principle is strictly adhered to but its properties in local space-time are derived from conservation principles, not inferred from a global field equation. The global field strength variation then gains some flexibility, but only in the regime of very strong fields (2nd-order terms) whose measurement is now being contemplated. So doing provides a family of similar gravities, differing only in strong fields, which could be developed into meaningful verification targets for strong fields after the manner in which far-field variations were used in the 20th century. General Relativity (GR) is shown to be a member of the family and this is demonstrated by deriving the Schwarzschild metric exactly from a suitable field strength assumption. The method of doing so is interesting in itself because it involves only one differential equation rather than the usual four. Exact static symmetric field solutions are also given for one pedagogical alternative based on potential, and one theoretical alternative based on inertia, and the prospects of experimentally differentiating these are analyzed. Whether the method overturns the conventional wisdom that GR is the only metric theory of gravity and that alternatives must introduce additional interactions and fields is somewhat semantical, depending on whether one views the field strength assumption as a field and whether the assumption that produces GR is considered unique in some way. It is of course possible to have other fields, and the local space-time principle can be applied to field gravities which usually are weak-field approximations having only time dilation, giving them the spatial factor and promoting them to full metric theories. Though usually pedagogical, some of them are interesting from a quantum gravity perspective. Cases are noted where mass measurement errors, or distributions of dark matter, can cause one

Disparities in Reportable Quality Metrics by Insurance Status in the Primary Spine Neoplasm Population

PubMed Central

Mehdi, Syed K.; Tanenbaum, Joseph E.; Alentado, Vincent J.; Miller, Jacob A.; Lubelski, Daniel; Benzel, Edward C.; Mroz, Thomas E.

2017-01-01

PSI (OR 1.81 95% CI 1.11– 2.95) relative to privately insured patients. CONCLUSIONS Among patients hospitalized for primary spinal neoplasms, primary payer status predicts the incidence of PSI, an indicator of adverse healthcare quality used to determine hospital reimbursement by CMS. As reimbursement continues to be intertwined with reportable quality metrics, identifying vulnerable populations is critical to improving patient care. PMID:27664341

Disparities in reportable quality metrics by insurance status in the primary spine neoplasm population.

PubMed

Mehdi, Syed K; Tanenbaum, Joseph E; Alentado, Vincent J; Miller, Jacob A; Lubelski, Daniel; Benzel, Edward C; Mroz, Thomas E

2017-02-01

ratio [OR] 1.81 95% confidence interval [CI] 1.11-2.95) relative to privately insured patients. Among patients hospitalized for primary spinal neoplasms, primary payer status predicts the incidence of PSI, an indicator of adverse health-care quality used to determine hospital reimbursement by the CMS. As reimbursement continues to be intertwined with reportable quality metrics, identifying vulnerable populations is critical to improving patient care. Copyright © 2016 Elsevier Inc. All rights reserved.

A Quantized Metric As an Alternative to Dark Matter

NASA Astrophysics Data System (ADS)

Maker, Joel

2010-03-01

The cosmological spherical symmetry background metric coefficient (g44≡) g00= 1-2GM/c^2r should be inserted into a Dirac equation σμ(gμμγ^μψ/xμ)-φψ = 0 (1,Maker) to make it generally covariant. The spin of this cosmological Dirac object is nearly unobservable due to inertial frame dragging and has rotational L(L+1) δɛ and oscillatory ɛ interactions with external objects at distance away r>>10^10 LY. The inside and outside frequencies φ match at the boundary allowing the outside metric eigenvalues to propagate inside. To include the correct 3 lepton masses in this Dirac equation we must use ansatz goo= e^i(2ɛ+δɛ) with ɛ=.06, δɛ=.00058. For local metric effects our ansatz is goo=e^iδɛ. Here the metric coefficient goo levels off to the quantized value e^iδɛ in the galaxy halo: goo=1-2GM/rc^2-> rel(e^iδɛ) =cos(δɛ)= 1-(δɛ)^2/2 ->(δɛ)^2/2=2GM/rc^2 for this circular motion v^2/r=GM/r^2=c^2(δɛ)^2/4r ->v^2 =c^2(δɛ)^2/4 =87km/sec)^2 100km/sec)^2. So the metric acts to quantize v. Note also there is rotational energy quantization for the δɛ rotational states that goes as: (L(L+1)) .5ex1 -.1em/ -.15em.25ex2 mv^2 ->√L(L+1) v. Thus differences in v are proportional to L, L being an integer. Therefore δv = kL so v = 1k, v = 2k, v = 3k, v = 4k. v=N (the above ˜100km/sec) with dark matter then not required to give these high halo velocities. Recent nearby galaxy Doppler halo velocity data strongly support this velocity quantization result.

Synthesized view comparison method for no-reference 3D image quality assessment

NASA Astrophysics Data System (ADS)

Luo, Fangzhou; Lin, Chaoyi; Gu, Xiaodong; Ma, Xiaojun

2018-04-01

We develop a no-reference image quality assessment metric to evaluate the quality of synthesized view rendered from the Multi-view Video plus Depth (MVD) format. Our metric is named Synthesized View Comparison (SVC), which is designed for real-time quality monitoring at the receiver side in a 3D-TV system. The metric utilizes the virtual views in the middle which are warped from left and right views by Depth-image-based rendering algorithm (DIBR), and compares the difference between the virtual views rendered from different cameras by Structural SIMilarity (SSIM), a popular 2D full-reference image quality assessment metric. The experimental results indicate that our no-reference quality assessment metric for the synthesized images has competitive prediction performance compared with some classic full-reference image quality assessment metrics.

A probability metric for identifying high-performing facilities: an application for pay-for-performance programs.

PubMed

Shwartz, Michael; Peköz, Erol A; Burgess, James F; Christiansen, Cindy L; Rosen, Amy K; Berlowitz, Dan

2014-12-01

Two approaches are commonly used for identifying high-performing facilities on a performance measure: one, that the facility is in a top quantile (eg, quintile or quartile); and two, that a confidence interval is below (or above) the average of the measure for all facilities. This type of yes/no designation often does not do well in distinguishing high-performing from average-performing facilities. To illustrate an alternative continuous-valued metric for profiling facilities--the probability a facility is in a top quantile--and show the implications of using this metric for profiling and pay-for-performance. We created a composite measure of quality from fiscal year 2007 data based on 28 quality indicators from 112 Veterans Health Administration nursing homes. A Bayesian hierarchical multivariate normal-binomial model was used to estimate shrunken rates of the 28 quality indicators, which were combined into a composite measure using opportunity-based weights. Rates were estimated using Markov Chain Monte Carlo methods as implemented in WinBUGS. The probability metric was calculated from the simulation replications. Our probability metric allowed better discrimination of high performers than the point or interval estimate of the composite score. In a pay-for-performance program, a smaller top quantile (eg, a quintile) resulted in more resources being allocated to the highest performers, whereas a larger top quantile (eg, being above the median) distinguished less among high performers and allocated more resources to average performers. The probability metric has potential but needs to be evaluated by stakeholders in different types of delivery systems.

Orthographic Stereo Correlator on the Terrain Model for Apollo Metric Images

NASA Technical Reports Server (NTRS)

Kim, Taemin; Husmann, Kyle; Moratto, Zachary; Nefian, Ara V.

2011-01-01

A stereo correlation method on the object domain is proposed to generate the accurate and dense Digital Elevation Models (DEMs) from lunar orbital imagery. The NASA Ames Intelligent Robotics Group (IRG) aims to produce high-quality terrain reconstructions of the Moon from Apollo Metric Camera (AMC) data. In particular, IRG makes use of a stereo vision process, the Ames Stereo Pipeline (ASP), to automatically generate DEMs from consecutive AMC image pairs. Given camera parameters of an image pair from bundle adjustment in ASP, a correlation window is defined on the terrain with the predefined surface normal of a post rather than image domain. The squared error of back-projected images on the local terrain is minimized with respect to the post elevation. This single dimensional optimization is solved efficiently and improves the accuracy of the elevation estimate.

Metrication study for large space telescope

NASA Technical Reports Server (NTRS)

Creswick, F. A.; Weller, A. E.

1973-01-01

Various approaches which could be taken in developing a metric-system design for the Large Space Telescope, considering potential penalties on development cost and time, commonality with other satellite programs, and contribution to national goals for conversion to the metric system of units were investigated. Information on the problems, potential approaches, and impacts of metrication was collected from published reports on previous aerospace-industry metrication-impact studies and through numerous telephone interviews. The recommended approach to LST metrication formulated in this study cells for new components and subsystems to be designed in metric-module dimensions, but U.S. customary practice is allowed where U.S. metric standards and metric components are not available or would be unsuitable. Electrical/electronic-system design, which is presently largely metric, is considered exempt from futher metrication. An important guideline is that metric design and fabrication should in no way compromise the effectiveness of the LST equipment.

Gridded global surface ozone metrics for atmospheric chemistry model evaluation

NASA Astrophysics Data System (ADS)

Sofen, E. D.; Bowdalo, D.; Evans, M. J.; Apadula, F.; Bonasoni, P.; Cupeiro, M.; Ellul, R.; Galbally, I. E.; Girgzdiene, R.; Luppo, S.; Mimouni, M.; Nahas, A. C.; Saliba, M.; Tørseth, K.

2016-02-01

The concentration of ozone at the Earth's surface is measured at many locations across the globe for the purposes of air quality monitoring and atmospheric chemistry research. We have brought together all publicly available surface ozone observations from online databases from the modern era to build a consistent data set for the evaluation of chemical transport and chemistry-climate (Earth System) models for projects such as the Chemistry-Climate Model Initiative and Aer-Chem-MIP. From a total data set of approximately 6600 sites and 500 million hourly observations from 1971-2015, approximately 2200 sites and 200 million hourly observations pass screening as high-quality sites in regionally representative locations that are appropriate for use in global model evaluation. There is generally good data volume since the start of air quality monitoring networks in 1990 through 2013. Ozone observations are biased heavily toward North America and Europe with sparse coverage over the rest of the globe. This data set is made available for the purposes of model evaluation as a set of gridded metrics intended to describe the distribution of ozone concentrations on monthly and annual timescales. Metrics include the moments of the distribution, percentiles, maximum daily 8-hour average (MDA8), sum of means over 35 ppb (daily maximum 8-h; SOMO35), accumulated ozone exposure above a threshold of 40 ppbv (AOT40), and metrics related to air quality regulatory thresholds. Gridded data sets are stored as netCDF-4 files and are available to download from the British Atmospheric Data Centre (doi: 10.5285/08fbe63d-fa6d-4a7a-b952-5932e3ab0452). We provide recommendations to the ozone measurement community regarding improving metadata reporting to simplify ongoing and future efforts in working with ozone data from disparate networks in a consistent manner.

Gridded global surface ozone metrics for atmospheric chemistry model evaluation

NASA Astrophysics Data System (ADS)

Sofen, E. D.; Bowdalo, D.; Evans, M. J.; Apadula, F.; Bonasoni, P.; Cupeiro, M.; Ellul, R.; Galbally, I. E.; Girgzdiene, R.; Luppo, S.; Mimouni, M.; Nahas, A. C.; Saliba, M.; Tørseth, K.; Wmo Gaw, Epa Aqs, Epa Castnet, Capmon, Naps, Airbase, Emep, Eanet Ozone Datasets, All Other Contributors To

2015-07-01

The concentration of ozone at the Earth's surface is measured at many locations across the globe for the purposes of air quality monitoring and atmospheric chemistry research. We have brought together all publicly available surface ozone observations from online databases from the modern era to build a consistent dataset for the evaluation of chemical transport and chemistry-climate (Earth System) models for projects such as the Chemistry-Climate Model Initiative and Aer-Chem-MIP. From a total dataset of approximately 6600 sites and 500 million hourly observations from 1971-2015, approximately 2200 sites and 200 million hourly observations pass screening as high-quality sites in regional background locations that are appropriate for use in global model evaluation. There is generally good data volume since the start of air quality monitoring networks in 1990 through 2013. Ozone observations are biased heavily toward North America and Europe with sparse coverage over the rest of the globe. This dataset is made available for the purposes of model evaluation as a set of gridded metrics intended to describe the distribution of ozone concentrations on monthly and annual timescales. Metrics include the moments of the distribution, percentiles, maximum daily eight-hour average (MDA8), SOMO35, AOT40, and metrics related to air quality regulatory thresholds. Gridded datasets are stored as netCDF-4 files and are available to download from the British Atmospheric Data Centre (doi:10.5285/08fbe63d-fa6d-4a7a-b952-5932e3ab0452). We provide recommendations to the ozone measurement community regarding improving metadata reporting to simplify ongoing and future efforts in working with ozone data from disparate networks in a consistent manner.

Changing to the Metric System.

ERIC Educational Resources Information Center

Chambers, Donald L.; Dowling, Kenneth W.

This report examines educational aspects of the conversion to the metric system of measurement in the United States. Statements of positions on metrication and basic mathematical skills are given from various groups. Base units, symbols, prefixes, and style of the metric system are outlined. Guidelines for teaching metric concepts are given,…

Implementing the Metric System in Agricultural Occupations. Metric Implementation Guide.

ERIC Educational Resources Information Center

Gilmore, Hal M.; And Others

Addressed to the agricultural education teacher, this guide is intended to provide appropriate information, viewpoints, and attitudes regarding the metric system and to make suggestions regarding presentation of the material in the classroom. An introductory section on teaching suggestions emphasizes the need for a "think metric" approach made up…