Problem Of Quality Assessment Research Articles

Predicting Display Visibility Under Dynamically Changing Lighting Conditions

AbstractDisplay devices, more than ever, are finding their ways into electronic consumer goods as a result of recent trends in providing more functionality and user interaction. Combined with the new developments in display technology towards higher reproducible luminance range, the mobility and variation in capability of display devices are constantly increasing. Consequently, in real life usage it is now very likely that the display emission to be distorted by spatially and temporally varying reflections, and the observer's visual system to be not adapted to the particular display that she is viewing at that moment. The actual perception of the display content cannot be fully understood by only considering steady‐state illumination and adaptation conditions. We propose an objective method for display visibility analysis formulating the problem as a full‐reference image quality assessment problem, where the display emission under “ideal” conditions is used as the reference for real‐life conditions. Our work includes a human visual system model that accounts for maladaptation and temporal recovery of sensitivity. As an example application we integrate our method to a global illumination simulator and analyze the visibility of a car interior display under realistic lighting conditions.

Evaluation of CASP8 model quality predictions

The model quality assessment problem consists in the a priori estimation of the overall and per-residue accuracy of protein structure predictions. Over the past years, a number of methods have been developed to address this issue and CASP established a prediction category to evaluate their performance in 2006. In 2008 the experiment was repeated and its results are reported here. Participants were invited to infer the correctness of the protein models submitted by the registered automatic servers. Estimates could apply to both whole models and individual amino acids. Groups involved in the tertiary structure prediction categories were also asked to assign local error estimates to each predicted residue in their own models and their results are also discussed here. The correlation between the predicted and observed correctness measures was the basis of the assessment of the results. We observe that consensus-based methods still perform significantly better than those accepting single models, similarly to what was concluded in the previous edition of the experiment.

Model quality assessment using distance constraints from alignments

Given a set of alternative models for a specific protein sequence, the model quality assessment (MQA) problem asks for an assignment of scores to each model in the set. A good MQA program assigns these scores such that they correlate well with real quality of the models, ideally scoring best that model which is closest to the true structure. In this article, we present a new approach for addressing the MQA problem. It is based on distance constraints extracted from alignments to templates of known structure, and is implemented in the Undertaker program for protein structure prediction. One novel feature is that we extract noncontact constraints as well as contact constraints. We describe how the distance constraint extraction is done and we show how they can be used to address the MQA problem. We have compared our method on CASP7 targets and the results show that our method is at least comparable with the best MQA methods that were assessed at CASP7. We also propose a new evaluation measure, Kendall's tau, that is more interpretable than conventional measures used for evaluating MQA methods (Pearson's r and Spearman's rho). We show clear examples where Kendall's tau agrees much more with our intuition of a correct MQA, and we therefore propose that Kendall's tau be used for future CASP MQA assessments.

Vibration-based skin damage statistical detection and restoration assessment in a stiffened aircraft panel

The combined problem of skin damage detection and restoration quality assessment in lightweight stiffened aircraft panels via vibration testing is considered. Two methods that employ statistical estimation and hypothesis testing procedures and are capable of accounting for experimental uncertainty are introduced. The first is parametric and employs natural frequency and damping ratio interval estimates. The second is non-parametric and employs coherence function interval estimates. The methods’ effectiveness is assessed through laboratory experiments with a stiffened aircraft panel. The results of the study indicate the feasibility of the vibration-based methodology for tackling both the skin damage detection and restoration quality assessment problems. It is also shown that the first method is effective for the skin damage detection problem, while the second for both the skin damage detection and restoration quality assessment problems.

Local quality assessment in homology models using statistical potentials and support vector machines

In this study, we address the problem of local quality assessment in homology models. As a prerequisite for the evaluation of methods for predicting local model quality, we first examine the problem of measuring local structural similarities between a model and the corresponding native structure. Several local geometric similarity measures are evaluated. Two methods based on structural superposition are found to best reproduce local model quality assessments by human experts. We then examine the performance of state-of-the-art statistical potentials in predicting local model quality on three qualitatively distinct data sets. The best statistical potential, DFIRE, is shown to perform on par with the best current structure-based method in the literature, ProQres. A combination of different statistical potentials and structural features using support vector machines is shown to provide somewhat improved performance over published methods.

Problems and Practical Solutions in the External Quality Control of Point of Care Devices with Respect to the Measurement of Blood Glucose

Point of care testing (POCT) is evolving at an ever increasing rate. This article deals mainly with the aspect of POCT for blood glucose and the problems of external quality assessment (EQA) of point of care devices (POCD). At the present time it is only possible to control precision with EQA, independent of the matrix of the test materials (synthetic polymer-base, plasma/serum, or processed whole blood). The German Federal Medical Council guidelines for laboratory performance allow an interlaboratory imprecision of +/-16%. The majority of POCD fulfill these requirements. The long-term stability of results--tested by repeated distribution of the same materials over a 12-month period--is excellent, and the performance of POCD under routine condtions is usually excellent in terms of result-comparability. The problems of accuracy in terms of control materials have still to be mastered.

Image information and visual quality

Measurement of visual quality is of fundamental importance to numerous image and video processing applications. The goal of quality assessment (QA) research is to design algorithms that can automatically assess the quality of images or videos in a perceptually consistent manner. Image QA algorithms generally interpret image quality as fidelity or similarity with a "reference" or "perfect" image in some perceptual space. Such "full-reference" QA methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychovisual features of the human visual system (HVS), or by signal fidelity measures. In this paper, we approach the image QA problem as an information fidelity problem. Specifically, we propose to quantify the loss of image information to the distortion process and explore the relationship between image information and visual quality. QA systems are invariably involved with judging the visual quality of "natural" images and videos that are meant for "human consumption." Researchers have developed sophisticated models to capture the statistics of such natural signals. Using these models, we previously presented an information fidelity criterion for image QA that related image quality with the amount of information shared between a reference and a distorted image. In this paper, we propose an image information measure that quantifies the information that is present in the reference image and how much of this reference information can be extracted from the distorted image. Combining these two quantities, we propose a visual information fidelity measure for image QA. We validate the performance of our algorithm with an extensive subjective study involving 779 images and show that our method outperforms recent state-of-the-art image QA algorithms by a sizeable margin in our simulations. The code and the data from the subjective study are available at the LIVE website.

Similarity-Based Objective Measure for Performance of Image Fusion

This paper considers the problem of quality assessment of image fusion result. A novel similarity-based measure for the performance of image fusion is proposed. From human visual features, this measure evaluates the similarity of the gradient fields between the source image and fused image. Compared with the existing similarity-based measures, the proposed one has an omnidirectional recognition ability; Compared with the mutual information method, it is more consistent with the human perception nature as it considers only the local image variations. Experimental results show that the proposed measure can evaluate the image fusion performance satisfactorily and is also perceptually meaningful.

An information fidelity criterion for image quality assessment using natural scene statistics

Measurement of visual quality is of fundamental importance to numerous image and video processing applications. The goal of quality assessment (QA) research is to design algorithms that can automatically assess the quality of images or videos in a perceptually consistent manner. Traditionally, image QA algorithms interpret image quality as fidelity or similarity with a "reference" or "perfecft" image in some perceptual space. Such "full-referenc" QA methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychovisual features of the human visual system (HVS), or by arbitrary signal fidelity criteria. In this paper, we approach the problem of image QA by proposing a novel information fidelity criterion that is based on natural scene statistics. QA systems are invariably involved with judging the visual quality of images and videos that are meant for "human consumption." Researchers have developed sophisticated models to capture the statistics of natural signals, that is, pictures and videos of the visual environment. Using these statistical models in an information-theoretic setting, we derive a novel QA algorithm that provides clear advantages over the traditional approaches. In particular, it is parameterless and outperforms current methods in our testing. We validate the performance of our algorithm with an extensive subjective study involving 779 images. We also show that, although our approach distinctly departs from traditional HVS-based methods, it is functionally similar to them under certain conditions, yet it outperforms them due to improved modeling. The code and the data from the subjective study are available at.

Preface

This collection of 10 papers, presented at the 5th International Symposium on the Sediment Quality Assessment (SQA5) in Chicago, IL, 16–18 October, 2002, offers to the reader a digest of the new trends in ‘Assessing Risk and Impacts of Contaminants in Sediments.’Hopefully this doesn't disappoint those comfortable with current approaches because new ideas and techniques are discussed which expand ways to tackle this complicated subject. For instance, Peter Chapman in his paper criticizes what seems to be written in stone, that is, Paracelsus’ dictum that ‘the right dose makes the poison.’ After (rightly) pointing out the many misinterpretations of this dictum by scientists, regulators and stakeholders, Dr. Chapman arrives at a new golden rule: ‘The right dose of a bioavailable substance, administered under realistic exposure conditions, differentiates a poison.’The examples (estuarine and freshwater stream communities) of the systematic approach to weight-of-evidence in sediment quality assessment provided by Valery Forbes and Peter Calow, nicely complements this view, suggesting a way to retrospectively assess sediment quality and successfully discriminate between possible stressors. And, again, Fred Lee and Anne Jones-Lee, further press the point that the presence alone of a chemical constituent in a sediment, by itself does not mean that an adverse effect will be manifested. I'm sure many will disagree with the statement that the ‘sediment quality guideline is technically invalid,’ but in this paper I found convincing evidence that we should move towards the non-numeric, triad weight of evidence approach suggested.Two papers by Tracey et al., in Louisiana, and by Dave and Nilsson, in Sweden report interesting results regarding the application of the Toxicity Identification Evaluation methodology. In both cases, the approach looks quite complicated, but yet, effective and useful . . . also raising more questions than providing answers!Many at the conference and in this issue point to the need and usefulness of new technical assessment tools. These could be special devices like the solid phase microextraction fibers used by Conder et al. to investigate the toxicity of nitroaromatic compounds, or special genomic techniques, like the gene expression fingerprinting employed by Perkins et al. to discriminate between different contaminant stress responses in chironomids, or the use of transgenic cell lines as a screening assay described by Inouye et al.The last two papers of this issue remind us that contaminated sediments are often not ‘only’ chemically polluted, especially in regards to human health where pathogenic microorganisms could be a serious concern. The Kinzelman et al. paper refers to a basic, but often overlooked factor: representative sampling. They suggest we should reconsider the way we approach this problem of sediment quality assessment. The other paper, by Indest et al., is even more critical of traditional microbiology, stating that ‘Current accepted bacterial indicator methods do not provide defensible data with respect to the occurrence and types of pathogens in sediments.’ So, it seems that we need to make more use of polymerase chain reaction techniques!Despite these calls for change, readers need not feel they must change everything they are currently doing. Be aware that these 10 papers are just examples of additional assessment tools and approaches which were discussed at SQA5. Additional papers from SQA5 are being processed currently which will be published in another special issue of the Journal!That's the real world: scientists seem to have endless ingenuity when it comes to finding new ways to assess risks and impacts of contaminants in sediments.

Assessing quality assessment of corporate social reporting: UK perspectives

This paper examines evaluation systems of UK corporate environmental and social reporting (CSR). Three issues are addressed: what do corporations and quality assessors (QAs) regard as quality CSR; problems with quality assessment in practice, and; formal monitoring processes and award schemes as a determinant and driver of CSR. Findings are informed by interviews with four UK-based assessment organisations and 60 corporate representatives. The paper concludes that: corporations adopt less comprehensive definitions of quality than QAs; QAs adopt more stringent definitions of quality than academics; methodological problems of quality assessment highlighted in the academic literature are experienced by QAs; and that benchmarking and award schemes are important drivers of CSR.

Color Quality Assessment of Different Implementations of JPEG2000

Colour images become abundant because of the low cost of the acquisition devices and the advent Internet. Starting from that, the definition of new algorithms for colour image processing is seen as extremely important. Among, these algorithms, the compression is of a high importance for applications such as archiving, transmission, etc. In addition, the availability of techniques allowing to compare faithfully the results quality is very necessary. The subjective evaluation of the colour image quality came into focus because of the “failure” of the objective criteria to offers good results in terms of human perception. In general, objective and subjective evaluation of compressed images can lead to significant different conclusions. This paper deals with the problem of quality assessment for the new compression standard JPEG2000. Its aim is to compare different implementation of the standard and to offer a point of view on the assessment of this kind of algorithms.

Nonlinear information aggregation via evidential reasoning in multiattribute decision analysis under uncertainty

In many decision situations, it is inevitable to deal with both quantitative and qualitative information under uncertainty. Evidence-based reasoning within a multiple criteria decision analysis framework provides an alternative way of handling such information systematically and consistently. In this paper, the evidential reasoning (ER) approach is introduced, which is based on a recursive ER algorithm that, in essence, constitutes a nonlinear information aggregation process. To facilitate the application of the ER approach and as an indispensable part of its development, the nonlinear features of the ER information aggregation process need to be thoroughly investigated and properly understood. This forms the theme of this paper where the nonlinear features are explored by examining typical reasoning patterns in aggregating harmonic, quasi-harmonic, and contradictory decision information. This analytical investigation provides insights into the recursive nature of the ER approach as well as valuable experience that could be useful to other researchers and practitioners interested in developing and applying operation research/artificial intelligence (OR/AI)-based approaches for decision analysis under uncertainty. The analytical study is complemented by the numerical studies of two application examples. The analysis of a quality assessment problem for motor engines is aimed to show the step-by-step process of implementing the ER approach and to illustrate its nonlinear features in a real-life decision situation. The study of a more complex assessment problem in ship design is intended to demonstrate the potential of the ER approach and its supporting software for dealing with general decision problems.

Problems of accreditation and quality assurance of engineering education in developing countries

The relationships between funding, management and quality assurance of engineering education in developing countries are discussed in this paper. It is proposed to raise the debate on engineering education up to the global economic level and to examine some of the issues facing developing and poorer countries in managing and improving the quality of engineering education in their countries. Since the fall of the Berlin Wall, the world is now divided in two realigned blocks: one of developed (rich or advanced) countries that have a social security safety net for their population and another of developing (or poor) countries that have no such luxuries for their population. For the general public in the developing countries, any engineering degree is a passport to lifelong well-being of an individual and his/her extended family.Therefore, the demand for such qualifications is very high and it is almost a rat race amongst school graduates to get into engineering/technical colleges. In view of this booming demand, there are hundreds of privately funded engineering/technical colleges in countries like the Philippines, India, Thailand, etc. besides state-funded ones. It is extremely difficult to ensure good quality in this mushrooming scenario. There are also many very small poorresource developing countries where there is only one engineering school and/or two to three technical colleges. Products of these schools/colleges work only in their own country and educational globalization has little or no meaning for them. Besides highlighting the aforementioned general issues, the paper also presents a few case studies on problems of accreditation and quality assessment in larger developing countries such as India and the Philippines and also in very small developing countries such as Papua New Guinea, Fiji and Arab countries.

Rx medication information for the public and the WWW: quality issues.

Misuse of prescription medications is a serious problem largely due to lack of information. Lay users are making use of resources available on the World Wide Web in order to bridge this information gap. It has already been noted though that health and medicine oriented sites present serious shortcomings with regard to quality and reliability of their content. In this review, checklists were used to determine to which extent the criteria suggested for quality evaluation of on-line health information are observed by sites offering information on Rx medications to the public. Also evaluated was the sites' comprehensiveness in coverage of important subject specific topics. The reviewed sites met inadequately the proposed quality criteria and presented significant variations in their coverage of the subject. Evaluation of information accuracy remains an unresolved problem in quality assessment, while techniques for automated review and retrieval are urgently needed. In the meantime, though, quality guidelines could prove more useful in getting valuable feedback from information providers and lay users alike, improving quality of information at its point of production.

Problems of Quality Assessment in Polish Higher Education

Beginning with a discussion of the need for and the criteria of quality assessment and accreditation in higher education, the author gives a rapid survey of western European practice. She then introduces the Polish situation in which two organizations have proposed higher education evaluation and accreditation systems: the General Council for Higher Education and the Institute of Contemporary Civilisation. Both organizations have developed pilot projects with selected Polish higher education institutions. The author summarizes the criteria and procedures of the evaluation systems of both organizations. She concludes by mentioning the results of a recent Polish‐American Seminar on Accreditation and Quality Assessment.

Clutch size in an obligately siblicidal parasitoid wasp

Insect parasitoids can be grouped by their pattern of brood production: ‘gregarious’ parasitoids can produce multiple offspring per host, but ‘solitary’ parasitoids can produce only a single offspring per host because their larval stages engage in lethal contest competition to monopolize the host resource. Theoretical and empirical studies have largely overlooked the possibility that solitary parasitoids may lay clutches of more than a single egg, leading to obligate siblicide. When this possibility has been recognized at all, it has been treated under the rubric of self-superparasitism (in which a parasitoid deposits eggs on the same host during two or more distinct host encounters). It is argued here, however, that multiple-egg clutches and self-superparasitism are fundamentally different behaviour patterns, entailing different potential costs and benefits. These differences are linked to variation in age structure within broods (self-superparasitism can produce mixed-age offspring within broods) and host quality assessment problems that are specific to self-superparasitism (during a second encounter, the parasitoid may not be able to assess its prior oviposition behaviour on the host). Clutch size was investigated in a solitary parasitoid wasp, Comperiella bifasciata(Howard) (Hymenoptera: Encyrtidae), that commonly produces multiple-egg clutches. Clutch size varied in response to aspects of the environment that were likely to shape the costs and benefits of multiple-egg clutches: larger clutches were produced when the parasitoid (1) had no contact with high-quality hosts and (2) experienced a high density of conspecific female parasitoids. Two types of costs are associated with depositing multiple-egg clutches: the opportunity cost of the extra egg(s) and the direct cost of the time required to deposit them. Multiple-egg clutches may represent a conditional strategy that increases reproductive success. A review of the literature shows that multiple-egg clutches are a widespread feature of the reproductive behaviour of solitary parasitoids.

A Statistical Method for Translation Quality Assessment1

AbstractThis paper attempts to introduce a new statistical method for making a quantitative assessment of the quality of a translation. A set of criteria was defined, against which the quality of a given unit of translation can be measured. These criteria provide a framework within which a mathematical model is constructed. It takes thefuzzy subset theoryas its theoretical basis, trying to solve the problem of translation quality assessment by an approach which might be called analysis-synthesis fuzzy evaluation. Mathematical operations can be performed with the aid of a computer program to yield a grade of membership which indicates the quality of a given translation. The model proposed in this paper is, therefore, of methodological significance.