Different Scales Of Measurement Research Articles

Electrical Responses of Modified Mineral Surfaces as Observed With Spectral Induced Polarization and Atomic Force Microscopy

AbstractAtomic force microscopy (AFM) and spectral induced polarization (SIP) are widely used to investigate the electrical properties of mineral surfaces at vastly different scales of measurement. We compare AFM and SIP measurements made on two different materials (glass beads and silica gel) subjected to etching, deposition of iron oxide particles, and inclusion of calcite grains. We found that the treatments produced qualitatively consistent behaviors in the AFM and SIP data. Direct AFM measurements of surface charge density for silica and calcite surfaces were quantitatively compared to values estimated from the SIP results using a grain polarization model. No statistically significant difference (at a 95% confidence level) was found between the surface charge density of silica estimated by AFM (2.3 ± 6.6 mC/m2 for glass beads and 1.6 ± 0.1 mC/m2 for silica gel) versus SIP (5.4 ± 4.4 mC/m2 for glass beads and 1.6 ± 0.5 mC/m2 for silica gel). The surface charge density for calcite determined by AFM (43.5 ± 12.9 mC/m2) was approximately 19 times higher than that found for silica. While the charge density of calcite surfaces determined by SIP was also generally higher than that found for silica, different treatments produced significantly different values between 4.7 and 258 mC/m2 (with a maximum 95% CI of ±8.7 mC/m2). Several possible explanations exist for the range of the observed SIP measurements, including aging of the calcite surfaces. Overall, this study suggests the potential for the complementary use of AFM and SIP measurements to constrain future investigations of polarization mechanisms in porous media.

Marked difference in liver fat measured by histology vs. magnetic resonance-proton density fat fraction: A meta-analysis

Pathologists quantify liver steatosis as the fraction of lipid droplet-containing hepatocytes out of all hepatocytes, whereas the magnetic resonance-determined proton density fat fraction (PDFF) reflects the tissue triacylglycerol concentration. We investigated the linearity, agreement, and correspondence thresholds between histological steatosis and PDFF across the full clinical spectrum of liver fat content associated with non-alcoholic fatty liver disease. Using individual patient-level measurements, we conducted a systematic review and meta-analysis of studies comparing histological steatosis with PDFF determined by magnetic resonance spectroscopy or imaging in adults with suspected non-alcoholic fatty liver disease. Linearity was assessed by meta-analysis of correlation coefficients and by linear mixed modelling of pooled data, agreement by Bland-Altman analysis, and thresholds by receiver operating characteristic analysis. To explain observed differences between the methods, we used RNA-seq to determine the fraction of hepatocytes in human liver biopsies. Eligible studies numbered 9 (N= 597). The relationship between PDFF and histology was predominantly linear (r= 0.85 [95% CI, 0.80-0.89]), and their values approximately coincided at 5% steatosis. Above 5% and towards higher levels of steatosis, absolute values of the methods diverged markedly, with histology exceeding PDFF by up to 3.4-fold. On average, 100% histological steatosis corresponded to a PDFF of 33.0% (29.5-36.7%). Targeting at a specificity of 90%, optimal PDFF thresholds to predict histological steatosis grades were ≥5.75% for ≥S1, ≥15.50% for ≥S2, and ≥21.35% for S3. Hepatocytes comprised 58 ± 5% of liver cells, which may partly explain the lower values of PDFF vs. histology. Histological steatosis and PDFF have non-perfect linearity and fundamentally different scales of measurement. Liver fat values obtained using these methods may be rendered comparable by conversion equations or threshold values. Magnetic resonance-proton density fat fraction (PDFF) is increasingly being used to measure liver fat in place of the invasive liver biopsy. Understanding the relationship between PDFF and histological steatosis fraction is important for preventing misjudgement of clinical status or treatment effects in patient care. Our analysis revealed that histological steatosis fraction is often significantly higher than PDFF, and their association varies across the spectrum of fatty liver severity. These findings are particularly important for physicians and clinical researchers, who may use these data to interpret PDFF measurements in the context of histologically evaluated liver fat content.

Supervised ML Algorithms in the High Dimensional Applications for Dimension Reduction

We steered comparative analysis of manifold supervised dimension reduction methods by assimilating customary multiobjective standard metrics and validated the comparative efficacy of supervised learning algorithms in reliance on data and sample complexity. The question of sample and data intricacy is deliberated in dependence on automating selection and user-purposed instances. Different dimension reduction techniques are responsive to different scales of measurement and supervision of learning is also discussed comprehensively. In line with the prospects, each technique validated diverse competence for different datasets and there was no mode to gauge the general ranking of methods trustily available. We especially engrossed the classifier ranking and concocted a system erected on weighted average rank called weighted mean rank risk adjusted model (WMRRAM) for consensus ranking of supervised learning classifier algorithms.

Alexithymia and Athletic Performance: Beneficial or Deleterious, Both Sides of the Medal? A Systematic Review.

Background: Numerous studies have been published on alexithymia among athletes in the last decades. The objective, here, is to provide a critical review on alexithymia in sport and identify elements demonstrating that alexithymic athletes can attain a competitive advantage. Methods: The Center for Reviews and Dissemination guidelines were used. The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines served as the template for reporting the present systematic review. We searched PubMed, Embase, Science Direct, and PsycINFO, without language or date restrictions. Results: Within 72 eligible studies, 23 articles fulfilling the selection criteria were included in the review. Alexithymia is associated with various pathologies and considered to be counter-performing. However, despite considerable suspicion of an advantageous performance effect of alexithymia, there is a lack of data to quantify this effect. Studies identified are heterogeneous (different scales of measurement of alexithymia used or outcomes, different sports), that do not allow us to conclude on an observed causal relationship, because the studies are mostly observational. Conclusion: This systematic review opens a new search field on alexithymia, as possibly promoting performance.

An Integrated Approach for Formation Micro-Image Rock Typing Based on Petrography Data: A Case Study in Shallow Marine Carbonates

Core rock-typing (RT) is commonly used for creating geologically reliable models of porous media in carbonate reservoirs. This approach is more advanced than the traditional porosity–permeability relationship and is based on the division of carbonate rocks into groups, using common classifications (lithofacies, FZI, Winland–Pittman, etc.). These clustering methods can provide either geological or petrophysical descriptions of the identified rock types. Besides, the connection of identified core rock types with standard logs could be challenging due to the different scales of measurement. This paper considers the creation of a new approach, named “integrated rock-typing,” which connects geologically and petrophysically driven rock types using borehole image logs. The methodology was applied to an Upper Devonian–Lower Carboniferous carbonate field. The workflow comprises borehole image structural/textural analysis with vug fraction identification, quantitative geological descriptions from thin sections, and petrophysical measurements. The geological section is divided into six rock types, which were controlled by sedimentary and diagenetic processes. The created Rock Type Catalogue provides clear links between rock types and log data, including wells with standard suites of logs. The results will be useful for geological modelling and validation of the future drilling strategy for the studied field.

Measuring Digital Citizenship: A Comparative Analysis

This paper aims at showing a state of the art about digital citizenship from the methodological point of view when it comes to measuring this construct. The review of the scientific literature offers at least ten definitions and nine different scales of measurement. The comparative and diachronic analysis of the content of the definitions shows us two conceptions of digital citizenship, some more focused on digital competences and others on critical and activist aspects. This paper replicates and compares three scales of measurement of digital citizenship selected for their relevance and administered in a sample of 366 university students, to analyze their psychometric properties and the existing coincidences and divergences between the three. The most outstanding conclusion is that not all of them seem to measure the same construct, due to its diversity of dimensions. An online activism dimension needs to be incorporated if digital citizenship is to be measured. There is an urgent need to agree internationally on a definition of digital citizenship with its corresponding dimensions to elaborate a reliable and valid measuring instrument.

Spatial mapping of COVID-19 for Indian states using Principal Component Analysis

Spatial mapping of COVID-19 for Indian states using Principal Component Analysis

Mapping natural resource collection areas from household survey data in Southern Africa

As conservation landscapes are threatened by global change, there is a growing need to understand relationships between human livelihoods and environmental processes. This often involves integrating multiple data sources capturing different scales of measurement. Participatory methods have emerged as a means to accomplish this, but are hampered by a wide range of challenges associated with data collection and translation. Here, we present a novel methodology for mapping human use of natural resources that overcomes many of the difficulties faced in participatory mapping. Based in the world's largest terrestrial transfrontier conservation area, we couple household surveys with in-situ fine-scale mapping to identify key resource areas that support local livelihoods. This allows for a spatially referenced human use ‘footprint’ that can be combined with remotely-sensed data measuring environmental impact. This methodology is applicable across contexts and has implications for landscape management and conservation.

Grey Absolute Decision Analysis (GADA) Method for Multiple Criteria Group Decision-Making Under Uncertainty

The study proposes a novel, convenient and dimensionless model of multi-criteria decision-making (MCDM), hereby referred to as Grey Absolute Decision Analysis (GADA) method. The foundation of the GADA method rests upon the Absolute Grey Relational Analysis (Absolute GRA) model and the system that the method follows to produce GADA Indexes and GADA Weights. The GADA Weights represent the relative weights of decision alternatives under given criteria. The method can handle both positive (“higher the better”) and negative (“lower the better”) criteria simultaneously in its algorithm. The method can deal with problems involving uncertainty and incomplete data. Two practical cases have been presented in the study to demonstrate the feasibility of the method. Furthermore, the GADA Weights obtained for the cases show that these values are comparable to the relative weights obtained through the traditional methods like AHP and SAW thus signifying the feasibility of the method. However, the conventional methods do not consider the mutual association between the judgments of the members of decision-making group (experts’ opinions), a weakness that the proposed method overwhelms. Therefore, the overall ranking obtained from the proposed method is acceptable, especially under the uncertain environment where the nature of mutual association between the judgments is not precise. The key benefit of the method lies in its adaptability to different scales of measurement. Also, it can provide relative weights and rankings of experts, criterion and alternatives. These benefits make the GADA method significant among the class of MCDM methods.

Scale, rank and model selection in evaluations of land cover influence on wildlife–vehicle collisions

Abstract ContextExamining land cover’s influences on roadkills at single predetermined scales is more common than evaluating multiple scales, but examining land cover at the appropriate scale may be necessary for efficient design of mitigation measures, and that appropriate scale may be difficult to discern a priori. In addition, the taxonomic rank at which data is analysed may influence results and subsequent conclusions concerning mitigation. AimsThe objective of the present study was to assess the influence of variation in spatial scales of land cover explanatory variables and taxonomic rank of response variables in models of wildlife–vehicle collisions (WVCs). Research questions include: (1) do the scales of land cover measurement that produce the highest quality models differ among species; (2) do the factors that influence roadkill events differ within species at different scales of measurement and among species overall; and (3) does the taxonomic rank at which data is analysed influence the selection of explanatory variables? MethodsFour frequent WVC species representing diverse taxonomic classes, i.e. two mammals (Cerdocyon thous and Hydrochaeris hydrochaeris), one reptile (Caiman yacare) and one bird (Caracara plancus), were examined. WVCs were buffered, land cover classes from classified satellite imagery at three buffer radii were extracted, and logistic regression model selection was used. Key resultsThe scale of land cover variables selected for the highest quality models (and the selected variables themselves) may vary among wild fauna. The same explanatory variables and formulae are not always included in the candidate models in all compared scales for a given species. Explanatory variables may differ among taxonomically similar species, e.g. mammals, and pooling species at higher taxonomic ranks can result in models that do not correspond with species-level models of all pooled species. ConclusionsThe most accurate analyses of WVCs will likely be found when species are analysed individually and multiple scales of predictor variable collection are evaluated. ImplicationsMitigating the effects of roadways on wildlife population declines for both common and rare species is resource intensive. Resources spent optimising models for spatially targeting management actions may reduce the amount of resources used and increase the effectiveness of these actions.

Incipient chemical weathering at bedrock fracture interfaces in a tropical critical zone system, Puerto Rico

Abstract The processes that control chemical weathering of bedrock in the deep critical zone at a mm-scale are still poorly understood, but may produce 100 s of meters of regolith and substantial fluxes of silicate weathering products and thus may be important for modeling long-term, global CO2. Weathering controls are also difficult to ascertain, as laboratory determined dissolution rates tend to be 2–5 orders of magnitude faster than field determined dissolution rates. This study aims to establish (i) the incipient processes that control the chemical weathering of the Bisley bedrock and (ii) why weathering rates calculated for the watershed may differ from laboratory rates (iii) why rates may differ across different scales of measurement. We analyzed mineralogy, elemental chemistry, and porosity in thin sections of rock obtained from drilled boreholes using Scanning Electron Microscopy (SEM) with energy dispersive spectrometry, electron probe microanalysis, and synchrotron-based Micro X-ray Fluorescence (µXRF) and X-ray Absorption Near Edge Structure (XANES). Weathering ages were determined from U-series isotope analysis. Mineral specific dissolution rates were calculated from solid-state mineralogical gradients and weathering ages. Mineralogical and elemental transects across thin sections and SEM images indicate that trace pyrite is the first mineral to dissolve. Micro-XRF mapping at 2 µm resolution revealed sulfate in pore space adjacent to dissolving pyrite, indicating that the incipient reaction is oxidative. The oxidative dissolution of pyrite produces a low pH microenvironment that aids the dissolution of pyroxene and chlorite. The rate-limiting step of weathering advance, and therefore the creation of the critical zone in the Bisley watershed, is pyrite oxidation, despite the low abundance (∼0.5 vol%) of pyrite in the parent rock. The naturally determined dissolution rates presented here either approach, converge with, or in some cases exceed, rates from the literature that have been experimentally determined. The U-series weathering age data on the mm-scale integrates the weathering advance rate over the ∼4.2 ± 0.3 kyrs that the weathering rind took to form. The weathering advance rate calculated at a watershed scale (from stream chemistry data) represents a contemporary weathering advance rate, which compares well with that calculated for the weathering rind, suggesting that the Bisley watershed has been weathering at steady-state for the last ∼4 kyrs.

Method for highly spatially resolved determination of residual stress by using nanoindentation

Measurement of highly spatially resolved residual stresses is a crucial task for tailoring the stress state during manufacturing to improve mechanical performance of metallic objects. Especially in sheet metal forming or blanking with sheet thicknesses down to 0.1 mm, a highly resolved pattern of the stress distribution over the sheet thickness is required for optimisation. For this purpose, a method which uses an extended Hertzian theory for calculating residual stresses from the results of nanoindentation is used to measure the stress profile in metallic cylinders. For verification of the indentation results, hole drilling is utilised to determine residual stresses in the near-surface area. This method provides similar assumptions about the stress state (biaxial). The measuring principle is also based on correlations between mechanical behaviour of the material and the residual stress distribution. The results yield a good accordance of the measured values despite the different scales of measurement. Therefore, a highly spatially resolved measurement of residual stresses with nanoindentation is possible and shows comparable values to the classic hole drilling technique.

Critical examination of evidence for the nutritional status of children in Papua New Guinea - a systematic review.

Undernutrition remains a significant cause of childhood illness, poor growth, development, and death in Papua New Guinea (PNG). Studies on child nutritional outcomes in PNG vary by design, measurement protocols and quality. We conducted a systematic review to assess the evidence for the prevalence of child undernutrition across different study populations, geographical locations and time periods. Six electronic databases and additional grey literature were searched for articles describing the nutritional status by wasting, stunting and underweight, of PNG children under five years of age, published between 1990 and April 2015. Prevalence data using different scales of measurement and reference populations were standardized according to WHO protocols. The search yielded 566 articles, of which, 31 studies met the inclusion criteria. The prevalence of child undernutrition varied from 1% to 76% for wasting (median 11%), 5% to 92% for stunting (median 51%), and 14% to 59% for underweight (median 32%). Wide variations exist according to the index used for measurement, the population characteristics and the geographical region in which they live. Prevalence estimates increase significantly when data using different scales of measurement and population references are standardized to the WHO protocols. Child undernutrition in PNG is regionally variable due to a complex interplay of poverty, disease, food-security, cultural, environmental and sociopolitical issues requiring a complex mix of solutions by governments, health systems and local communities. Area- specific surveys using multiple measures are necessary to inform local solutions for this important problem.

Platelet function testing in cardiac surgery: A comparative study of electrical impedance aggregometry and thromboelastography

Point of care platelet function tests are increasingly used to assess drug-related platelet inhibition prior to cardiac surgery. Numerous devices are available including Thromboelastography (TEG® PlateletMapping™). The latest generation TEG® – the TEG® 6 – has recently been released incorporating a cartridge-based system with a PlateletMapping cartridge. In this study, the performance of the TEG® 6 PlateletMapping was compared to that of Multiple Electrode Aggregometry (MEA) performed with the Multiplate™. Preoperative platelet function tests were performed on 50 cardiac surgery patients. Two sets of tests were performed using arachidonic acid and ADP assessing for aspirin and ADP antagonists, respectively, assessing the MEA area under the curve (AUC) in comparison to the TEG® maximal amplitude (MA) and percentage inhibition. For both arachidonic acid and ADP, the MEA AUC did not correlate with either the TEG® MA or % inhibition by Pearson’s correlation. The Bland–Altman plots, however, indicated that there might be good agreement between the tests with either reagents, accounting for the different scales of measurement.

NEURAL NETWORK MODELING IN PROBLEMS OF PREDICTION MODES OF ELECTRICAL GRIDS

Purpose. Form a neuro-fuzzy network based on temperature monitoring of overhead transmission line for the prediction modes of the electrical network. Methodology. To predict the load capacity of the overhead line architecture provides the use of neuro-fuzzy network based on temperature monitoring of overhead line. The proposed neuro-fuzzy network has a four-layer architecture with direct transmission of information. To create a full mesh network architecture based on hybrid neural elements with power estimation accuracy of the following two stages of the procedure: - in the first stage a core network (without power estimation accuracy) is generated; - in the second stage architecture and network parameters are fixed obtained during the first stage, and it is added to the block estimation accuracy, the input signals which are all input, internal and output signals of the core network, as well as additional input signals. Results. Formed neuro-fuzzy network based on temperature monitoring of overhead line. Originality. A distinctive feature of the proposed network is the ability to process information specified in the different scales of measurement, and high performance for prediction modes mains. Practical value. The monitoring system will become a tool parameter is measuring the temperature of the wire, which will, based on a retrospective analysis of the accumulated information on the parameters to predict the thermal resistance of the HV line and as a result carry out the calculation of load capacity in real time.

Meta-analysis of genome-wide association from genomic prediction models.

SummaryGenome‐wide association (GWA) studies based on GBLUP models are a common practice in animal breeding. However, effect sizes of GWA tests are small, requiring larger sample sizes to enhance power of detection of rare variants. Because of difficulties in increasing sample size in animal populations, one alternative is to implement a meta‐analysis (MA), combining information and results from independent GWA studies. Although this methodology has been used widely in human genetics, implementation in animal breeding has been limited. Thus, we present methods to implement a MA of GWA, describing the proper approach to compute weights derived from multiple genomic evaluations based on animal‐centric GBLUP models. Application to real datasets shows that MA increases power of detection of associations in comparison with population‐level GWA, allowing for population structure and heterogeneity of variance components across populations to be accounted for. Another advantage of MA is that it does not require access to genotype data that is required for a joint analysis. Scripts related to the implementation of this approach, which consider the strength of association as well as the sign, are distributed and thus account for heterogeneity in association phase between QTL and SNPs. Thus, MA of GWA is an attractive alternative to summarizing results from multiple genomic studies, avoiding restrictions with genotype data sharing, definition of fixed effects and different scales of measurement of evaluated traits.

Empathy in Korean medical students: Findings from a nationwide survey

Background: Previous studies on empathy in Korean medical students were conducted on small populations or with different scales of measurement, resulting in low representativeness and generalisability of the findings.Aim: To evaluate empathy in Korean medical students throughout the country and to make suggestions to improve empathy.Methods: The Jefferson Scale of Empathy (JSE) (Korean) was used, and the impact of sex, age, the medical school admission system, and grade of the respondents was investigated.Results: We analyzed 5343 questionnaires and found a mean empathy score of 105.9 ± 12.8. Females and post-baccalaureate students had higher scores as compared with their counterparts. There was a significant difference between the admission systems after controlling for gender. Students from higher grade levels had lower scores than those from the lower grade levels.Conclusions: The JSE score of Korean medical students was lower than that of students in Western countries. The difference of gender and medical school admission system should be considered, and capability to apply empathy to clinical practice should be focused upon in medical training.

Differing effects of attention in single-units and populations are well predicted by heterogeneous tuning and the normalization model of attention

Single-unit measurements have reported many different effects of attention on contrast-response (e.g., contrast-gain, response-gain, additive-offset dependent on visibility), while functional imaging measurements have more uniformly reported increases in response across all contrasts (additive-offset). The normalization model of attention elegantly predicts the diversity of effects of attention reported in single-units well-tuned to the stimulus, but what predictions does it make for more realistic populations of neurons with heterogeneous tuning? Are predictions in accordance with population-scale measurements? We used functional imaging data from humans to determine a realistic ratio of attention-field to stimulus-drive size (a key parameter for the model) and predicted effects of attention in a population of model neurons with heterogeneous tuning. We found that within the population, neurons well-tuned to the stimulus showed a response-gain effect, while less-well-tuned neurons showed a contrast-gain effect. Averaged across the population, these disparate effects of attention gave rise to additive-offsets in contrast-response, similar to reports in human functional imaging as well as population averages of single-units. Differences in predictions for single-units and populations were observed across a wide range of model parameters (ratios of attention-field to stimulus-drive size and the amount of baseline response modifiable by attention), offering an explanation for disparity in physiological reports. Thus, by accounting for heterogeneity in tuning of realistic neuronal populations, the normalization model of attention can not only predict responses of well-tuned neurons, but also the activity of large populations of neurons. More generally, computational models can unify physiological findings across different scales of measurement, and make links to behavior, but only if factors such as heterogeneous tuning within a population are properly accounted for.

On The Organization Of Human T Cell Receptor Loci

T cell repertoire in health and disease is complex, comprised of millions of unique T cell clones defined by hetero-dimeric T cell receptors (TCR). The a and b subunits of the TCR are products of genetic loci consisting of variable (V) and joining (J) segments in the case of TCR a (TRA), and V, J and diversity (D) segments in the case of TCR b (TRB). These gene segments are recombined to yield TCR a (VJ) or TCR b (VDJ). Recently we reported that T cell clonal frequency in normal stem cell donors, from the point of view of TCR b gene segment usage rather than being random, has a fractal ordering (Meier et al, BBMT 2013). Fractals are mathematical constructs characterized by self-similarity at different scales of measurement. Thus whether T cell repertoire is examined from the standpoint of DJ, VDJ or VDJ+nucleotide inserted TCR b clones the frequency distribution remains the same when log transformed data are examined yielding a fractal dimension (FD) of ~ 1.5.In order to identify the origin of the observed fractal ordering of TCR b gene segment containing clones, the distribution of gene segments across the TRA and TRB loci was evaluated for self-similarity. Data describing the numeric positions of the initial and final nucleotides of the start and stop codons respectively, was obtained for each gene segment on the two loci was from the NCBI public data base. Resulting gene segment length and intervening space between successive gene segments (in base pairs) were calculated and log-transformed to assess self-similarity by calculating FD using the formula, FD = Log (magnitude)/Log (scaling factor). Length of individual gene segments was considered as scaling factor and the inter-segment space, as the magnitude of the line segment; FD was calculated for each segment. This demonstrated that the V and J gene segments for both TRA and TRB loci were arranged in a fractal, self-similar manner when the spacing between the loci was considered as a function of the size of the gene segment. Despite the apparent variability in the observed sizes of the V and J gene segments and the spacing between them, on a logarithmic scale there was marked uniformity in their size and spacing, with an average FD of 1.4±0.1 and 1.3±0.2 for TRB, V and J segments respectively (Figure). Corresponding values for TRA locus were 1.5±0.1 and 1.7±0.1, for the V and J segments. [Display omitted] During T cell receptor recombination, the J and the D segments in TRA and TRB loci respectively, are recombined with the V segments therefore the distribution of each V segment in the TRA and TRB loci was determined relative to the position of the J and the D segments in the respective loci, by the using the following formula spacing V-J or V-D = INP-D or J segment / INP nthV segment, (INP: initial nucleotide positions of gene segments). This measure demonstrated a strikingly consistent proportionality across both TRA and TRB loci, and when plotted for successive V segments on the TRB locus, the value declined logarithmically, with a slope of approximately 1.6, and similarly an average slope of 1.3 for the TRA locus, consistent with the earlier observed FD for these loci. We conclude that T cell receptor gene segments are organized in an iterating logarithmically scaled manner. This implies that aside from mechanisms such as the 12/23 rule, gene segment distribution across the T cell receptor loci may help determine the order of recombination, and thus contribute to the observed fractal ordering of the T cell repertoire. Disclosures:No relevant conflicts of interest to declare.

Comparison of requirements prioritization techniques employing different scales of measurement

The objective of this paper is to conduct a controlled experiment with the three requirements prioritization techniques: Numerical Assignment (NA), Analytic Hierarchy Process (AHP) and Extensive Numerical Assignment (ENA), each based on ordinal, ratio and interval scales respectively. NA and AHP are widely used traditional requirements prioritization techniques. ENA is a novel technique introduced by the authors, which acknowledges the uncertain and incomplete nature of human judgment about requirements priorities, which are in turn uncertain guesses about the upcoming product. The aim of the experiment is to examine the three techniques using various objective and subjective measures like number of decisions, time consumption, ease of use, attractiveness, scalability and reprioritizability. The experiment was executed by prioritizing the requirements of a university website system with students as participants in the experiment. The results of the experiment proved that ENA transcends NA and AHP.