Consistent Quality Control Research Articles

A Content-Aware Video Encoding Scheme Based on Single-Pass Consistent Quality Control

In real-time video streaming applications based on battery-powered camera systems, it is crucial to capture and transmit critical information satisfying the storage capacity and channel bandwidth requirement. In this paper, we propose a single-pass content-aware video encoding scheme for such applications to achieve a consistent video quality while satisfying the bit-rate constraints. To achieve the objective we developed: 1) scene descriptor based on the discrete cosine transformation coefficients obtained from the video encoder; 2) a parameterized analytic distortion model for video encoding using the scene descriptor; 3) scene change detection based on the encoded MB mode ratio; and 4) a single-pass consistent video quality control scheme which exploits 1), 2), and 3). Experimental results show that the proposed method results in less deviation from the target distortion and less distortion variance than the up-to-date best result by up to 65.25% and 75.88%, respectively, while satisfying the given rate constraints. The computing time overhead in the proposed method was 0.560% and 0.571% for the variable and constrained variable bit-rate mode, respectively, which is negligible in nearly all embedded applications.

Consistent quality control in ECG compression by means of direct metrics

The aim of electrocardiogram (ECG) compression is to reduce the amount of data as much as possible while preserving the significant information for diagnosis. Objective metrics that are derived directly from the signal are suitable for controlling the quality of the compressed ECGs in practical applications. Many approaches have employed figures of merit based on the percentage root mean square difference (PRD) for this purpose. The benefits and drawbacks of the PRD measures, along with other metrics for quality assessment in ECG compression, are analysed in this work. We propose the use of the root mean square error (RMSE) for quality control because it provides a clearer and more stable idea about how much the retrieved ECG waveform, which is the reference signal for establishing diagnosis, separates from the original. For this reason, the RMSE is applied here as the target metric in a thresholding algorithm that relies on the retained energy. A state of the art compressor based on this approach, and its PRD-based counterpart, are implemented to test the actual capabilities of the proposed technique. Both compression schemes are employed in several experiments with the whole MIT–BIH Arrhythmia Database to assess both global and local signal distortion. The results show that, using the RMSE for quality control, the distortion of the reconstructed signal is better controlled without reducing the compression ratio.

Quality control of chemical libraries

The complete sequence of the human genome has been deciphered at the dawn of the new century. This historic event immediately challenged researchers with new needs both in terms of concepts and of working methods. Each scientific community considered how it could tackle these new challenges and it quickly became clear that using small chemical molecules would help discovering and characterizing the function of new proteins. The importance of the genes that the encode new proteins could thus be established in cells, organs and whole organisms. At the initiative of a handful of researchers, French chemists have organized the collection of their molecules and provided them to biologists. By doing so they killed two birds with one stone: on the one hand they created a unique opportunity to add value to their molecules by creating the first academic chemical library, and on the other hand they stimulated the launch of biologically active molecules discovery programs by biologists from the academic sector. It was necessary, however, to raise many compounds and ensure consistent quality control, which quickly became a priority for the chemical libraries to become reliable tools.

Development of Quality Control Method for a Novel Herbal Medicine, HPL-1 using UHPLC

Objectives : HPL-1, a novel herbal medicine which is composed of five herbs such as Kalopanacis Cortex, Chaenomelis Fructus, Raphani Semen, Atractylodis Rhizoma and Pulvis Aconiti Tuberis Purificatum, was developed for treatment of osteoarthritis. This study is aimed to develop analytical method for consistent quality control of HPL-1 and validate chromatographic method. Methods : Chromatographic analysis was performed using ultra-high performance liquid chromatography diode array detector (UHPLC-DAD) equipped with RP-amide column, column oven, and auto sampler. Marker compounds [protocatechuic acid, chlorogenic acid, liriodendrin, 3,5-dicaffeoylquinic acid, β -D-(3-O-sinapoyl)fructofuranosyl-α -D-(6-O-sinapoyl)glucopyranoside and benzoylmesaconine] were separated by step gradient elution of acetonitrile and 0.1% phosphoric acid/water. The method validation was evaluated by quantitative validation parameters of linearity, accuracy, precision, limit of detection (LOD) and limit of quantification (LOQ) according to KFDA guideline. Results : An optimized method for six marker compounds in HPL-1 was established by UHPLC-DAD. The correlation coefficient (R 2 ) with each calibration curve was greater than 0.99. The LOD and LOQ were within the range of 0.008-0.090 and 0.023-0.274 µg/mL, respectively. The relative standard deviation (RSD) of intra- and inter-day variability were less than 4.0%. The result of recovery test was range from 93.3-106.3% with RSD < 4.0%. Conclusions : These results suggest that the quantitative UHPLC method is precise, accurate, effective for quality evaluation of HPL-1. The method may also contribute to improve quality of crude drug preparations used for treatment of various diseases.

Quality Control and Reproducibility in M-Mode, Two-Dimensional, and Speckle Tracking Echocardiography Acquisition and Analysis: The CARDIA Study, Year 25 Examination Experience.

Few large studies describe quality control procedures and reproducibility findings in cardiovascular ultrasound, particularly in novel techniques such as speckle tracking echocardiography (STE). We evaluate the echocardiography assessment performance in the Coronary Artery Risk Development in Young Adults (CARDIA) study Year 25 (Y25) examination (2010-2011) and report findings from a quality control and reproducibility program conducted to assess Field Center image acquisition and reading center (RC) accuracy. The CARDIA Y25 examination had 3475 echocardiograms performed in 4 US Field Centers and analyzed in a RC, assessing standard echocardiography (LA dimension, aortic root, LV mass, LV end-diastolic volume [LVEDV], ejection fraction [LVEF]), and STE (two- and four-chamber longitudinal, circumferential, and radial strains). Reproducibility was assessed using intraclass correlation coefficients (ICC), coefficients of variation (CV), and Bland-Altman plots. For standard echocardiography reproducibility, LV mass and LVEDV consistently had CV above 10% and aortic root below 6%. Intra-sonographer aortic root and LV mass had the most robust values of ICC in standard echocardiography. For STE, the number of properly tracking segments was above 80% in short-axis and four-chamber and 58% in two-chamber views. Longitudinal strain parameters were the most robust and radial strain showed the highest variation. Comparing Field Centers with echocardiography RC STE readings, mean differences ranged from 0.4% to 4.1% and ICC from 0.37 to 0.66, with robust results for longitudinal strains. Echocardiography image acquisition and reading processes in the CARDIA study were highly reproducible, including robust results for STE analysis. Consistent quality control may increase the reliability of echocardiography measurements in large cohort studies.

An Integrated Sustainable Business and Development System: Thoughts and Opinions

Companies understand the importance of monitoring and managing their environmental impacts and aim to integrate, with consistent quality control, effective reduce-reuse-recycle programs and risk preventions. By building an integrated sustainable business and development system to meet certain environmental standards, many companies are eligible to be “green” certified. Companies may consider recognizing global visions on sustainability while implementing local best practices. An integrated sustainable business and development system includes talent management, sustainable supply chain, practicing strategies of leveraging resources effectively, implementing social responsibilities, initiating innovative programs of recycling, reducing, and reusing, advancing leaders’ perceptions towards sustainability, reducing innovation barriers, and engaging sustainable practices strategically.

Consistent Video Quality Control in Scalable Video Coding Using Dependent Distortion Quantization Model

Consistent video quality control is an important and practical issue for video streaming applications. Several algorithms have been developed in the literature that aims to maintain consistent quality through the entire video sequence, whereas most of them focus on non-scalable video coding. In this paper, we propose an algorithm for consistent quality control for H.264/AVC based scalable video coding (SVC), relying on a dependent distortion-quantization (D-Q) model. Such a dependent D-Q model is developed to capture the distortion behavior of frames at enhancement layers (ELs) by exploring the correlation between two successive layers. Experimental results demonstrate that the proposed model can accurately estimate the distortion of each frame at different layers in the quality, temporal, and spatial scalability. The proposed model is applied in SVC where the quantization parameter of each frame at EL is carefully selected to achieve consistent video quality given the distortion constraint. Meanwhile, model parameters are initialized using the content features extracted from the underlying video sequences, and updated using the encoded data at the frame level. Simulations show that the proposed scheme enables more stable video quality with the PSNR keeping close to the target value (i.e., small PSNR variation).

Integration of Arrival-Time Datasets for Consistent Quality Control: A Case Study of Amphibious Experiments along the Middle America Trench

We have integrated waveform and arrival‐onset data collected in Costa Rica as part of the National Science Foundation (NSF)‐sponsored Costa Rica Seismogenic Zone Experiment (CRSEIZE) and along central Costa Rica and Nicaragua as part of the German SFB 574 program. The five arrays, composed of different sensor types (one‐ and three‐component land and ocean bottom seismometers and hydrophones), were archived using different software packages (Antelope and SEISAN) and were automatically and manually picked using various quality criteria resulting in a disparate set of pick weights. We evaluate pick quality using automated arrival detection and picking algorithm based on the wavelet transform and Akaike information criterion picker. The consistency of the arrival information over various scales provides a basis for assigning a quality to the analyst pick. Approximately 31% of P arrival times and 26% of S times have been classified as high‐quality picks (quality 0–1). An additional 21% of P times and 27% of S arrivals are good quality (quality 2–3). The revised quality picks are mapped directly into new pick weights for inversion studies. We explore the effect of new weighting and removal of poor data by relocating hypocenters through a minimum 1D velocity model and conducting double‐difference local earthquake tomography (LET). Analysis of the hypocenter relocation and seismic velocity tomography results suggest that using the improved quality determinations have a greater effect on improving sharpness in the velocity images than on the magnitude of hypocentral movement. Online Material: Figures of waveforms, event statistics, and tomography; and tables of station and event parameters, station qualities, velocity model, and hypocentral parameters.

Consistent Visual Quality Control in Video Coding

Visual quality consistency is one of the most important issues in video quality assessment. When people view a sequential video, they may have an unpleasant perceptual experience if the video has an inconsistent visual quality even though the average visual quality of the video is not compromised. Thus, consistent visual quality control is mostly expected in general video encoding with limited channel bandwidth and buffer resources. However, there still has not been enough study on such an issue. In this paper, a new objective visual quality metric (VQM) is proposed first, which can easily be incorporated into video coding for guiding video coding. Second, a VQM-based window model is proposed to handle the tradeoff between visual quality consistency and buffer constraint in video coding. Third, a window-level rate control algorithm is developed to accomplish visual quality control based on the above two proposals. Finally, experimental results prove that consistent visual quality, high rate-distortion efficiency, accurate bit control, and compliant buffer constraint can be achieved by the proposed rate control algorithm.

CistromeFinder for ChIP-seq and DNase-seq data reuse

Chromatin immunoprecipitation and DNase I hypersensitivity assays with high-throughput sequencing have greatly accelerated the understanding of transcriptional and epigenetic regulation, although data reuse for the community of experimental biologists has been challenging. We created a data portal CistromeFinder that can help query, evaluate and visualize publicly available Chromatin immunoprecipitation and DNase I hypersensitivity assays with high-throughput sequencing data in human and mouse. The database currently contains 6378 samples over 4391 datasets, 313 factors and 102 cell lines or cell populations. Each dataset has gone through a consistent analysis and quality control pipeline; therefore, users could evaluate the overall quality of each dataset before examining binding sites near their genes of interest. CistromeFinder is integrated with UCSC genome browser for visualization, Primer3Plus for ChIP-qPCR primer design and CistromeMap for submitting newly available datasets. It also allows users to leave comments to facilitate data evaluation and update. http://cistrome.org/finder. xsliu@jimmy.harvard.edu or henry_long@dfci.harvard.edu.

Quality control of tuirejieduling granules using high-performance liquid chromatography fingerprint method and simultaneous determination of four main active ingredients

Background:The Tuirejieduling granule is a compound preparation made from four kinds of Chinese medicines. It is effective for anti-inflammation, antivirus, defervescence and anti-bacterium; however, its quality control standards have remained unknown.Objective:To establish a simple and accurate fingerprint method for quality control of the Tuirejieduling granule.Materials and Methods:The methanol extract of the Tuirejieduling granule was used for the fingerprint analysis and the four selected active ingredients (epigoitrin, phillyrin, saikosaponin A and glycyrrhetinic acid) in the extract were determined. The fingerprint method was performed on an Amethyst C18-P chromatography column by gradient elution with acetonitrile and aqueous phase (containing 0.5% H3PO4 (v/v), pH 3.0).Results:Under the optimal chromatographic condition, twenty peaks were chosen as fingerprint peaks of the Tuirejieduling granules extractions. The similarities of 10 batches of Tuirejieduling granule was more than 0.99. This indicates that the different batches of Tuirejieduling granules were under the consistent quality control. Good linear behaviors over the investigated concentration ranges were obtained with the values of R2 higher than 0.99 for four studied active ingredients. The recoveries for spiked samples were in the range of 96.2–105.5%. The developed method was successfully applied to determine the contents of active constituents in different batches of Tuirejieduling granule.Conclusion:The HPLC fingerprint was proved to be a reliable method for the quality control of Tuirejieduling granule.

Measurement of flowability of lubricated powders by the vibrating tube method

Background: The evaluation of lubricity or flowability of pharmaceutical powders is important for consistent production and quality control of drug products. However, there have been only a few studies on quantitative measurements of the properties of lubricated powders.Method: Magnesium stearate (MgSt) and sodium stearyl fumarate (SSF) were used as lubricants. Lubricated powders were prepared by adding lubricants to spray-dried lactose under different conditions. To evaluate flowability, the vibrating tube method was used. In this method, the vibration amplitude of the tube is increased at a constant rate, and the mass of the powder discharged from the tube is recorded. Flowability profiles, i.e. the relationships between the mass flow rate and vibration acceleration, were obtained experimentally. To characterize static and dynamic friction properties of powders, critical vibration acceleration required to make powder particles flow and the average mass flow rate were determined.Results: Addition of 0.5% MgSt was sufficient for the reduction of static friction between particles. Blending time of the lubricants had little effect on the average mass flow rate of lubricated powders. On the other hand, addition of SSF resulted in an increase in static friction at the beginning of blending, and after a certain blending time, flowability improved. The combination of MgSt and SSF improved both static and dynamic friction properties irrespective of the blending time.Conclusion: The vibrating tube method can be used to evaluate the flowability properties of lubricated powders, and the experimental results provide useful information on the production of pharmaceutical solid dosage forms.

ОсобливостІ використаннЯ спеціальниХ автоматичниХ регуляторіВ длЯ нестаціонарниХ теХнологічниХ об'єктіВ

The analysis of technological properties of objects that belong to a class of non-stationary. A special structure and special controls used to ensure consistent quality control processes

A magnetic method for non destructive monitoring of fiber dispersion and orientation in steel fiber reinforced cementitious composites. Part 2: Correlation to tensile fracture toughness

Successful application with advanced fiber reinforced cement based materials relies on reliable design prescriptions and design-oriented test methodologies for the identification of relevant material properties, together with consistent and effective quality control procedures. The “randomly uniform” dispersion of fibers within a structural element is a crucial issue to be tackled, which, if not achieved, may lead to the activation of unanticipated failure mechanisms, thus lowering the load bearing capacity and jeopardizing the structural performance. It is henceforth evident that non-destructive techniques for fiber dispersion monitoring need to be developed and calibrated, as it has been going on for at least the last lustrum, and their outcomes to be effectively correlated to the mechanical performance of the material. In this paper a non-destructive method based on the magnetic properties of the composite has been applied to monitor the fiber dispersion and orientation in HPFRCC slabs. The results have been correlated to the tensile behaviour, measured according to the newly conceived “Double Edge Wedge Splitting” technique. The work herein presented stands as a step towards the assessment of non-destructive methods for fiber dispersion monitoring and their inclusion into a sound quality control procedure in a design oriented perspective.

Parametric design and process parameter optimization for bra cup molding via response surface methodology

Seamless and traceless undergarments have rendered foam sheet molding as an important manufacturing technique for the intimate apparel industry. Seamless bra cups are made by one-step forming technology. The three-dimensional (3D) cup shape is formed by using high temperatures and pressures with flexible polyurethane foams. Nevertheless, the mold head design process and control of the bra cup molding process are highly complicated and error prone. There is limited knowledge about the effects of foam properties, molding parameters and foam cup geometric parameters on molding process optimization. This research presents a response surface methodology as the approach for parametric design and process parameter optimization of bra cup molding. The proposed approach integrates 3D scanning via reverse engineering, parameterized-based remeshing and registration algorithm, non-linear mathematical prediction models for cup shape conformity, a model of foam shrinkage and example-based bra cup design and grading to optimize the bra cup development and production process. The experimental results show that this method is highly effective and more timesaving in the design and development of new products, as well as providing consistent quality control of the bra cup molding process.

Consistent manufacturing and quality control of a highly complex recombinant polyclonal antibody product for human therapeutic use

The beneficial effect of antibody therapy in human disease has become well established mainly for the treatment of cancer and immunological disorders. The inherent monospecificity of mAbs present limitations to mAb therapy which have become apparent notably in addressing complex entities like infectious agents or heterogenic endogenous targets. For such indications mixtures of antibodies comprising a combination of specificities would convey more potent biological effect which could translate into therapeutic efficacy. Recombinant polyclonal antibodies (rpAb) consisting of a defined number of well-characterized mAbs constitute a new class of target specific antibody therapy. We have developed a cost-efficient cell banking and single-batch manufacturing concept for the production of such products and demonstrate that a complex pAb composition, rozrolimupab, comprising 25 individual antibodies can be manufactured in a highly consistent manner in a scaled-up manufacturing process. We present a strategy for the release and characterization of antibody mixtures which constitute a complete series of chemistry, manufacturing, and control (CMC) analytical methods to address identity, purity, quantity, potency, and general characteristics. Finally we document selected quality attributes of rozrolimupab based on a battery of assays at the genetic-, protein-, and functional level and demonstrate that the manufactured rozrolimupab batches are highly pure and very uniform in their composition.

HLA genotyping in the international Type 1 Diabetes Genetics Consortium

Background Although human leukocyte antigen (HLA) DQ and DR loci appear to confer the strongest genetic risk for type 1 diabetes, more detailed information is required for other loci within the HLA region to understand causality and stratify additional risk factors. The Type 1 Diabetes Genetics Consortium (T1DGC) study design included high-resolution genotyping of HLA-A, B, C, DRB1, DQ, and DP loci in all affected sibling pair and trio families, and cases and controls, recruited from four networks worldwide, for analysis with clinical phenotypes and immunological markers.Purpose In this article, we present the operational strategy of training, classification, reporting, and quality control of HLA genotyping in four laboratories on three continents over nearly 5 years.Methods Methods to standardize HLA genotyping at eight loci included: central training and initial certification testing; the use of uniform reagents, protocols, instrumentation, and software versions; an automated data transfer; and the use of standardized nomenclature and allele databases. We implemented a rigorous and consistent quality control process, reinforced by repeated workshops, yearly meetings, and telephone conferences.Results A total of 15,246 samples have been HLA genotyped at eight loci to four-digit resolution; an additional 6797 samples have been HLA genotyped at two loci. The genotyping repeat rate decreased significantly over time, with an estimated unresolved Mendelian inconsistency rate of 0.21%. Annual quality control exercises tested 2192 genotypes (4384 alleles) and achieved 99.82% intra-laboratory and 99.68% inter-laboratory concordances.Limitations The chosen genotyping platform was unable to distinguish many allele combinations, which would require further multiple stepwise testing to resolve. For these combinations, a standard allele assignment was agreed upon, allowing further analysis if required.Conclusions High-resolution HLA genotyping can be performed in multiple laboratories using standard equipment, reagents, protocols, software, and communication to produce consistent and reproducible data with minimal systematic error. Many of the strategies used in this study are generally applicable to other large multi-center studies.

The IR Radlex Project: An Interventional Radiology Lexicon—A Collaborative Project of the Radiological Society of North America and the Society of Interventional Radiology

The IR Radlex Project: An Interventional Radiology Lexicon—A Collaborative Project of the Radiological Society of North America and the Society of Interventional Radiology

Consistent Picture Quality Control Strategy for Dependent Video Coding

Typically, a video rate control algorithm minimizes the average distortion (denoted as MINAVE) at the cost of large temporal quality variation, especially for videos with high motion and frequent scene changes. To alleviate the negative effect on subjective video quality, another criterion that restricts a small amount of quality variation among adjacent frames is preferred for practical applications. As pointed out by [20], although some existing proposals can produce consistent quality videos, they often fail to fully utilize the available bits to minimize the global total distortion. In this paper, we would like to achieve the triple goal of consistent quality video, minimizing the total distortion, and meeting the bit budget strictly all at the same time on the interframe dependent coding structure. Two approaches are taken to accomplish this goal. In the first algorithm, a trellis-based framework is proposed. One of our contributions is to derive an equivalent condition between the distortion minimization problem and the budget minimization problem. Second, our trellis state (tree node) is defined in terms of distortion, which facilitates the consistent quality control. Third, by adjusting one key parameter in our algorithm, a solution in between the MINAVE and the constant quality criteria can be obtained. The second approach is to combine the Lagrange multipliers method together with the consistent quality control. The PSNR performance is degraded slightly but the computational complexity is significantly reduced.Simulation results show that both our approaches produce a much smaller PSNR variation at a slight average PSNR loss as compared to the MPEG JM rate control. When they are compared to the other consistent quality proposals, only the proposed algorithms can strictly meet the target bit budget requirement (no more, no less) and produce the largest average PSNR at a small PSNR variation.

Continuing decline in hormone therapy use: population trends over 17 years

Objective To describe the prevalence of menopausal hormone therapy (HT) in 2008 and trends over the last 17 years in an Australian population.Methods Data were obtained from nine representative population face-to-face interview surveys of the South Australian population from 1991 to 2008. The surveys used consistent method and quality control procedures. In 2008, demographic data, HT use and eight dimensions of health, using the SF-36 health survey questionnaire, were measured.Participants Over 3000 South Australian adults were interviewed in their own home by trained health interviewers in each of the surveys; in the 2008 survey, 1555 women participated, of whom 953 were over age 40.Results After a peak in use in the 2000 survey, HT use fell from 2003 and has continued to decline in 2008. In 2008, current use over age 50 of registered conventional HT products is now 11.8%, with a further 4.0% using non-registered alternative ‘hormonal’ products. Current HT use is highest between the ages of 50 and 59 years, where 13.4% use conventional HT and 7.7% use unconventional alternative hormones. Use of these unregistered hormonal products was rare in previous surveys. Median and mean length of conventional HT use were 10.0 and 10.5 years, respectively. HT users continued to have a demographic profile similar to those in previous surveys, i.e. they were better educated, employed, partnered, had a higher income and were less inclined to use complementary and alternative medicines.Conclusions There has been a continuing decline in both the overall prevalence and length of use of conventional HT from 2003, probably in association with negative media about HT. Of medical concern is that about one-quarter of women using HT around menopause now chooses unregistered hormonal mixtures that are untested for long-term safety and efficacy.