Non-critical Regions Research Articles

Automatic thresholding method using single information entropy under product transformation of order difference filter response

To automatically threshold images with unimodal, bimodal, multimodal or non-modal gray level distributions within a unified framework, an automatic thresholding method using single information entropy under the product transformation of order difference filter response is proposed. The proposed method first performs the product transformation of order difference filter response on an input image at different scales to obtain the product transformation image. Critical or non-critical pixels are labelled on each pixel of the binary images corresponding to different thresholds to construct a series of binary label images that are used for distinguishing critical or non-critical regions. A single information entropy is finally used for characterizing the information obtained from the product transformation image with the critical regions of different binary label images, and the threshold corresponding to maximum information entropy is selected as final threshold. The proposed method is compared with seven state-of-the-art segmentation methods. Experimental results on 12 synthetic images and 98 real-world images show that the average Matthews correlation coefficients of the proposed method reached 0.994 and 0.966 for the synthetic images and the real-world images, which outperform the second-best method by 52.4 % and 27.8 %, respectively. The proposed method has more robust segmentation adaptability to test images with different modalities, despite not offering an advantage in terms of computational efficiency.

Application of volume‐translated rescaled perturbed‐chain statistical associating fluid theory equation of state to pure compounds using an expansive experimental database

AbstractThe performance of the perturbed‐chain statistical associating fluid theory‐type equations of state (PC‐SAFT‐type EOSs) is compromised in predicting properties of pure compounds in the critical region. In our previous research, we introduced an improved volume‐translated rescaled PC‐SAFT EOS (VTR‐PC‐SAFT EOS) by incorporating a dimensionless distance‐function. Such VTR‐PC‐SAFT EOS is built based on a critical point‐based PC‐SAFT EOS that can reproduce the critical temperature, critical pressure, and critical molar volume of pure compounds. VTR‐PC‐SAFT EOS is found to significantly improve the accuracy of phase behavior predictions in both critical and noncritical regions for pure compounds. In this study, we assess the performance of VTR‐PC‐SAFT EOS in reproducing the critical and noncritical properties of 251 pure compounds, encompassing 20 distinct chemical species. The testing results indicate that, compared to the other three PC‐SAFT‐type EOSs, the VTR‐PC‐SAFT EOS can consistently provide more accurate representations of critical and noncritical properties of 251 pure compounds.

Two natural toughening strategies may inspire sustainable structures

Contemporary designs of engineering structures strive to minimize the use of material in order to reduce cost and weight. However, the approach taken by focusing on materials selection and on the design of the exterior shape of structures has reached its limits. By contrast, nature implements bottom-up designs based on a multiple-level hierarchy, spanning from nanoscale to macroscale, which evolved over millions of years in an environmentally sustainable manner given limited resources. Natural structures often appear as laminates in wood, bone, plants, exoskeletons, etc., and employ elaborate micro-structural mechanisms to generate simultaneous strength and toughness. One such mechanism, observed in the scorpion cuticle and in the sponge spicule, is the grading (gradual change) of properties like layers thickness, stiffness, strength and toughness. We show that grading is a biological design tradeoff, which optimizes the use of material to enhance survival traits such as endurance against impending detrimental cracks. We found that such design, when applied in a more vulnerable direction of the laminate, has the potential to restrain propagation of hazardous cracks by deflecting or bifurcating them. This is achieved by shifting material from non-critical regions to more critical regions, making the design sustainable in the sense of efficient use of building resources. We investigate how such a mechanism functions in nature and how it can be implemented in synthetic structures, by means of a generic analytical model for crack deflection in a general laminate. Such a mechanical model may help optimize the design of bioinspired structures for specific applications and, eventually, reduce material waste.

Self-aware face emotion accelerated recognition algorithm: a novel neural network acceleration algorithm of emotion recognition for international students.

With an increasing number of human-computer interaction application scenarios, researchers are looking for computers to recognize human emotions more accurately and efficiently. Such applications are desperately needed at universities, where people want to understand the students' psychology in real time to avoid catastrophes. This research proposed a self-aware face emotion accelerated recognition algorithm (SFEARA) that improves the efficiency of convolutional neural networks (CNNs) in the recognition of facial emotions. SFEARA will recognize that critical and non-critical regions of input data perform high-precision computation and convolutive low-precision computation during the inference process, and finally combine the results, which can help us get the emotional recognition model for international students. Based on a comparison of experimental data, the SFEARA algorithm has 1.3× to 1.6× higher computational efficiency and 30% to 40% lower energy consumption than conventional CNNs in emotion recognition applications, is better suited to the real-time scenario with more background information.

An improved volume translation model for PC-SAFT EOS based on a distance function

In this study, we develop an improved volume-translation model for perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EOS). The new volume translation model is based on a distance function that measures the distance between the current condition and a critical point. This volume translation model is integrated into a particular version of PC-SAFT, which can exactly reproduce the critical points of pure compounds. The proposed volume-translated PC-SAFT EOS is found to exactly reproduce the critical properties of pure compounds (including critical pressure, critical temperature, and critical molar volume) and yield accurate reproductions of the saturated liquid density, liquid density, and vapor pressure of the selected 39 pure fluids over a wide range of temperatures and pressures, covering the critical and non-critical regions. Overall, the newly developed volume-translated SAFT EOS model yields average absolute percentage deviations (%AADs) of only 0.505, 0.470, and 0.676, in reproducing the saturated liquid density, liquid density, and vapor pressure, respectively.

Two-scale modeling of particle crack initiation and propagation in particle-reinforced composites by using microscale analysis based on Voronoi cell finite element model

In this study, a two-scale finite element model has been developed for the elastic analysis of composite materials. The coarse finite element mesh was assumed for the macroscale analysis, while Voronoi cell finite element model (VCFEM) was used for the microscale analysis of heterogeneous domains. The adaptive coupling between the two scales in non-critical and critical regions was accomplished through the master–slave nodes method. Two scale elements were connected together through the use of shared nodes and the order of the edge displacement interpolation. A new extended VCFEM was proposed to simulate particle damage generation, and a remeshing algorithm was constructed to simulate particle crack generation and propagation in particle-reinforced composites. For crack propagation analysis, four new combined Voronoi elements were developed and analyzed at the microscale. The obtained results for the stresses, stress intensity factors, and crack path were compared with those calculated using the commercial calculation software Abaqus. The two sets of results are in very good agreement, confirming the accuracy of the proposed method used for determining the stress concentrations and also for coarse-mesh discretization.

A Place-based Assessment of Flash Flood Hazard and Vulnerability in the Contiguous United States

Flash flood is among the most catastrophic natural hazards which causes disruption in the environment and societies. Flash flood is mainly initiated by intense rainfall, and due to its rapid onset (within six hours of rainfall), taking action for effective response is challenging. Building resilience to flash floods require understanding of the socio-economic characteristics of the societies and their vulnerability to these extreme events. This study provides a comprehensive assessment of socio-economic vulnerability to flash floods and investigates the main characteristics of flash flood hazard, i.e. frequency, duration, severity, and magnitude. A socio-economic vulnerability index is developed at the county level across the Contiguous United States (CONUS). For this purpose, an ensemble of social and economic variables from the US Census and the Bureau of Economic Analysis were analyzed. Then, the coincidence of socio-economic vulnerability and flash flood hazard were investigated to identify the critical and non-critical regions. Results show that the southwest U.S. experienced severe flash flooding with high magnitude, whereas the Northern Great Plains experience lower severity and frequency. Critical counties (high-vulnerable-hotspot) are mostly located in the southern and southwestern parts of the U.S. The majority of counties in the Northern Great Plains indicate a non-critical status.

Multipartite nonlocality and boundary conditions in one-dimensional spin chains

In quantum lattice models, in the large-$N$ limit, boundary conditions have little effect upon local observables for sites in the centers of the lattices. In this paper, we will study the boundary effects upon multipartite nonlocality (a kind of multipartite quantum correlation associated with Bell-type inequalities) in one-dimensional finite-size spin chains, both for zero temperature and for finite temperatures. We define a quantity $\frac{\ensuremath{\delta}\mathcal{S}}{\mathcal{S}}$ to characterize the boundary effects, where $\mathcal{S}$ is a measure of global multipartite nonlocality of the entire lattice, and $\ensuremath{\delta}\mathcal{S}$ is the difference of the measure induced by changing the boundary conditions. We find $\frac{\ensuremath{\delta}\mathcal{S}}{\mathcal{S}}$ does not vanish in the large-$N$ limit. Instead, at zero temperature, with the increase of $N$, $\frac{\ensuremath{\delta}\mathcal{S}}{\mathcal{S}}$ would increase steadily in the vicinity of the quantum phase transition point of the models, and converge to a nonzero constant in noncritical regions. It shows clearly that boundary effects generally exist, in the form of multipartite correlations, in long chains. The boundary effects are explained by the competition between the two orders of the models. In addition, based on these numerical results, we construct a Bell inequality, which is violated by chains with periodic (closed) boundary conditions and not violated by chains with open boundary conditions. Furthermore, we study $\frac{\ensuremath{\delta}{\mathcal{S}}_{T}}{{\mathcal{S}}_{T}}$ of finite-size chains at finite temperatures, and show that boundary effects survive in finite temperature regions.

Impacts of Operators’ Behavior on Reliability of Power Grids During Cascading Failures

Human operators play a key role in the reliable operation of critical infrastructures. However, human operators may take actions that are far from optimum. This can be due to various factors affecting the operators’ performance in time-sensitive and critical situations such as reacting to contingencies with significant monetary and social impacts. In this paper, an analytic framework is proposed based on Markov chains for modeling the dynamics of cascading failures in power grids. The model captures the effects of operators’ behavior quantified by the probability of human error under various circumstances. In particular, the observations from historical data and information obtained from interviews with power-system operators are utilized to develop the model as well as identify its parameters. In light of the proposed model, the noncritical regions of power-system's operating characteristics with human-factor considerations are characterized under which the probability of large cascading failures is minimized.

Reliability-based design optimization with frequency constraints using a new safest point approach

ABSTRACTIn the reliability-based design optimization (RBDO) model, the mean values of uncertain variables are usually applied as design variables, and the cost is optimized subject to prescribed probabilistic constraints as defined by a nonlinear mathematical programming problem. Therefore, an RBDO solution that reduces the structural weight in non-critical regions provides not only an improved design, but also a higher level of confidence in the design. Solving such nested optimization problems is extremely expensive for large-scale multidisciplinary systems that are likewise computationally intensive. This article focuses on the study of a particular problem representing the failure mode of structural vibration analysis. A new method is proposed, called safest point, that can efficiently give the reliability-based optimum solution under frequency constraints, and then several probability distributions are developed, which are mathematically nonlinear functions, for the proposed method. Finally, the efficiency of the extended approach is demonstrated for probability distributions such as log-normal and uniform distributions, and its applicability to the design of structures undergoing fluid–structure interaction phenomena, especially the design process of aeroelastic structures, is also demonstrated.

Asymmetric criticality of ionic solution containing 1-hexyl-3-methylimidazolium tetrafluoroborate and 2-propanol

The liquid–liquid coexistence curve for binary solution {2-propanol+1-hexyl-3-methylimidazolium tetrafluoroborate ([C6mim][BF4])} has been measured. The isobaric heat capacities per unit volume were obtained in both critical and non-critical regions. The critical exponents α and β were deduced and showed good agreement with those predicted for the 3D-Ising universality class. The asymmetric behaviour of the diameter of the coexistence curve was analysed based on the complete scaling theory, which indicated that the heat capacity related term plays an important role in describing the asymmetric behaviour of the coexistence curve. Furthermore, the RPM (restricted primitive model)-rescaled critical parameters were calculated and suggested the solvophobic criticality for this system.

Critical phenomena in {bromobenzene + 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide} binary solution

The liquid-liquid coexistence curve for binary solution {bromobenzene + 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C6mim][NTf2])} has been measured in both critical and non-critical regions. The isobaric heat capacities per unit volume were measured in one-phase and two-phase regions. Moreover, the turbidity measurements were also performed in the near-critical one-phase region. From the liquid-liquid equilibrium, heat capacity and turbidity data collected in the critical region, the critical exponents α, β, γ and ν were obtained and shown to be consistent with those predicted for the 3D-Ising universality class. The universal critical amplitude ratios RB and X have been calculated and shown to reasonably coincide with the theoretical predicted values. The asymmetric behavior of the diameter of the coexistence curve was well described by the complete scaling theory, provided that the heat capacity related term was considered. Moreover, the coulombic criticality of the studied system was indicated by the small values of RPM reduced critical density and critical temperature.

Fidelity spectrum: A tool to probe the property of a quantum phase**Project supported by the Earmarked Research Grant from the Research Grants Council of HKSAR, China (Grant No. CUHK 401212).

Fidelity measures the similarity between two states and is widely adapted by the condensed matter community as a probe of quantum phase transitions in many-body systems. Despite its success in witnessing quantum critical points, information about the fine structure of a quantum phase one can get from this approach is still limited. Here, we proposed a scheme called fidelity spectrum. By studying the fidelity spectrum, one can obtain information about the characteristics of a phase. In particular, we investigated the spectra in the one-dimensional transverse-field Ising model and the two-dimensional Kitaev model on a honeycomb lattice. It was found that the spectra have qualitative differences in the critical and non-critical regions of the two models. From the distributions of them, the dominating k modes in a particular phase could also be captured.

Abstract 4925: Liquid biopsy using the ion AmpliSeq v2 cancer panel

Abstract Introduction: Plasma cell-free circulating tumor DNA (ctDNA) has the potential to serve as a noninvasive surrogate to determine tumor genotype and monitor treatment response. Here we report the analytical validation of the Ion AmpliSeq v2 Cancer Panel (ACP) in plasma ctDNA samples. Methods: Mutations were assessed using the ACP, designed to survey 2800 mutations in 50 cancer-related genes. TruQ reference standards were used to determine LOD. Healthy donor and cancer patient plasma samples were used for other studies. Eight libraries were barcoded and sequenced with PGM sequencing 200 kit v2 on a 318 v2 chip. The sequencing data were analyzed with a combination of Torrent Suite 3.4.2, VarScan, our proprietary analysis pipeline and IGV. The background noise level of hotspot nt positions was calculated from multiple runs of known wild type DNA. In order to increase the sensitivity of the assay to detect low-level mutation, a custom program was developed to detect variants clearly different from background noise (95% confidence) and not reported by the two variant callers. PCR methods were used for concordance testing. Results: The performance characteristics of the AmpliSeq v2 Cancer Panel were demonstrated in 1) Minimum DNA input and LOD: With 10 ng DNA input, 43/43 and 42/43 expected mutations were detected at 2.5% or 1%, respectively. With 1 ng DNA input, 42/43 and 40/43 expected mutations were detected at 2.5% and 1%, respectively. 2) Coverage: The mean library coverage for 40 plasma libraries was 2912x with only 5 non-critical regions below 250x coverage. 3) Baseline error rate: 95% of 2290 hot-spots for SBS showed <0.5% background error frequency assessed in 10 healthy control ctDNA samples. The mean background error frequency plus two folds of SD falls below 0.5% for 91% of SBS hot-spots. 4)Precision: All mutations expected for TruQ6 were detected in 4 independent runs at observed allele frequencies with 0.6% mean SD and 0.1% mean deviation from the true value. A 2% TP53 mutation R174W was reproducibly detected in a lung cancer plasma sample in 2 independent runs. 5) Concordance study: Consistent results were observed for 3 positive (Allele Freq 40%, 3% and 0.2%, respectively) and 3 negative melanoma plasma samples previously genotyped by AS-PCR for Braf V600E/K mutations. Additional cancer patient ctDNA samples are being assessed for concordance in the detection of other mutations. Conclusions: The ACP offers a useful tool for comprehensive somatic mutation profiling in ctDNA. The limit of detection is 1-2% mutation frequency for most mutations with slight variation across different nucleotide positions. The low concentration of ctDNA obtained from plasma samples can present a challenge. Less than 10 ng DNA input may result in allele drop out for low level mutations due to the inefficient amplification of multiplex PCR compared with PCR methods using a short length single amplicon. Higher DNA input to rescue allele drop-out is under evaluation. Citation Format: WeiHua Liu, Zhenyu Yan, Candice L. Horn, Fabio Nunes, Steven M. Bray, Philip J. Ebert, Peng Fang, Jennifer Biroschak, Cindy Spittle, Chad Galderisi, Jin Li. Liquid biopsy using the ion AmpliSeq v2 cancer panel. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4925. doi:10.1158/1538-7445.AM2015-4925

MECP2, a gene associated with Rett syndrome in humans, shows conserved coding regions, independent Alu insertions, and a novel transcript across primate evolution.

BackgroundThe methyl-CpG Binding Protein two gene (MECP2) encodes a multifunctional protein comprising two isoforms involved in nuclear organization and regulation of splicing and mRNA template activity. This gene is normally expressed in all tissues, with a higher expression level in the brain during neuronal maturation. Loss of MECP2 function is the primary cause of Rett syndrome (RTT) in humans, a dominant, X-linked disorder dramatically affecting neural and motor development.ResultsWe investigated the molecular evolution of MECP2 in several primate taxa including 36 species in 16 genera of neotropical (platyrrhine) primates. The coding region of the MECP2_e2 isoform showed a high level of evolutionary conservation among humans and other primates, with amino acid substitutions in 14 codons and one in-frame insertion of a single serine codon, between codons 357 and 358, in Ateles paniscus. Most substitutions occurred in noncritical regions of MECP2 and the majority of the algorithms used for analyzing selection did not provide evidence of positive selection. Conversely, we found 48 sites under negative selection in different regions, 23 of which were consistently found by three different algorithms. Similar to an inverted Alu insert found previously in a lesser ape at a parallel location, one Alu insertion of approximately 300 bp in Cebus and Sapajus was found in intron 3. Phylogenetic reconstruction of the intron 3 data provided a topology that was coincident with the consensus arrangement of the primate taxa. RNAseq data in the neotropical primate Callimico goeldii revealed a novel transcript consisting of a noncontinuous region of the human-homologous intron 2 in this species; this transcript accounted for two putative polypeptides.ConclusionsDespite the remarkable evolutionary conservation of MECP2, one in-frame codon insertion was observed in A. paniscus, and one region of intron 3 was affected by a trans-specific Alu retrotransposition in two neotropical primate genera. Moreover, identification of novel MECP2 transcripts in Callimico suggests that part of a homologous human intronic region might be expressed, and that the potential open reading frame in this region might be a subject of interest in RTT patients who carry an apparently normal MECP2 sequence.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0240-x) contains supplementary material, which is available to authorized users.

Global quantum discord in matrix product states and the application

Global quantum discord (GQD) is a measure of quantum correlation for multi-site quantum states. In this paper, we propose an efficient procedure to calculate global quantum discord (Gn) for consecutive n-site subsystems in infinite-size matrix product states (MPSs). We apply the method to study the scaling behavior of Gn in several one-dimensional infinite quantum spin chains, i.e., (1) a three-site interaction model whose ground state can be exactly expressed as MPSs, and (2) a spin-12 XXZ chain whose ground state is approximately expressed as MPSs with the help of infinite time-evolving block decimation (iTEBD) algorithm. In both models, as the increase of n, Gn shows an approximately linear growth. Unambiguous clue for the convergence of the incremental ΔGn=Gn−Gn−1 is observed when n is large enough. Moreover, in non-critical (gapped) regions ΔGn converges very fast, while in critical (gapless) regions it converges relatively slow. The behaviors are explained in a model-independent physical picture with finite-range correlations. Based on these results, we propose to use “discord per site” (Gnn) to describe the global correlations in infinite-size spin chains. Moreover, we find that the global discord shows a size-independent maximum at the infinite-order quantum phase transition point of the XXZ model.

Asymmetric criticality of binary ionic solutions containing 1-butyl-3-methylimidazolium tetrafluoroborate and alcohol.

The liquid-liquid coexistence curves for binary solutions {1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) + 1-propanol} and {1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) + 2-propanol} have been precisely measured. The values of the critical exponents β obtained from the liquid-liquid equilibrium data in the critical region confirmed the 3D-Ising universality. The isobaric heat capacities per unit volume were measured for {[C4mim][BF4] + 1-propanol (or 2-propanol, 1,3-propanediol, 1,4-butanediol)} in both critical and non-critical regions. The experimental results indicate a major solvophobic contribution to the criticality for the studied ionic solutions. The complete scaling theory was applied to well represent the asymmetric behavior of the diameter of the coexistence curves with the consideration of the heat capacity contribution. It was found that the contribution of the heat capacity related term in the ionic solution decreased with the increase of the permittivity of alcohol and was more important in the description of the asymmetry of the coexistence curve of the ionic solutions than that of the molecular solutions.

Asymmetric criticality of the osmotic compressibility in binary mixtures

Heat capacities in the critical and the non-critical regions for {benzonitrile + tridecane} and {benzonitrile + pentadecane}, and light scattering for {benzonitrile + undecane}, {benzonitrile + dodecane}, {benzonitrile + tridecane}, {benzonitrile + tetradecane}, {benzonitrile + pentadecane}, and {benzonitrile + hexadecane} in the critical two-phase region were measured. Light scattering measurements confirmed the existence of the asymmetry for the osmotic compressibility while no such asymmetry was observed for the correlation length. An analysis of the osmotic compressibility asymmetry suggested the dominance of the singular term |ΔT[circumflex]|(β), which supports the complete scaling theory. The consistency of the complete scaling theory in descriptions of different asymmetry behaviors was also discussed. Moreover, it was found that the contribution of the heat capacity-related term is also important in describing the asymmetry of the osmotic compressibility as it was observed in studies of the diameters of the coexistence curves.

Motion of apical and laminal /s/ in normal and post-glossectomy speakers

There are two ways to produce an `s' in English: apical and laminal. They are almost identical perceptually and the reason for choosing one type is not well understood. This study questions whether one type is preferred in certain conditions, such as high vs low palate height or in post surgical tongue adaptation. This study examines palate height, and motion of critical and non-critical tongue regions in 8 normal speakers and 8 post-glossectomy patients who have had surgical resection of squamous cell carcinomas of the tongue. Speech was recorded with tagged-MRI and processed to track displacement and velocity of 2-D midsagittal tongue tissue points in the tongue tip and body during the utterance of the word “a souk”. Results indicate that subject category had a greater effect on s motion than palate height. Both critical and non-critical articulators in subjects with apical s used higher velocity and displacement on average than subjects with laminal s. Compared to patients with larger resections, patients with smaller resections had larger velocities and displacements in both tongue areas suggesting less debility. The single patient with flap reconstruction showed the highest velocity and greatest displacement, suggesting a different type of articulatory compensation. This research was supported in part by NIH R01 CA133015

Numerical analysis of regenerative cooling in liquid propellant rocket engines

High combustion temperatures and long operation durations require the use of cooling techniques in liquid propellant rocket engines (LPRE). For high-pressure and high-thrust rocket engines, regenerative cooling is the most preferred cooling method. Traditionally, approximately square cross sectional cooling channels have been used. However, recent studies have shown that by increasing the coolant channel height-to-width aspect ratio and changing the cross sectional area in non-critical regions for heat flux, the rocket combustion chamber gas-side wall temperature can be reduced significantly without an increase in the coolant pressure drop. In this study, the regenerative cooling of a liquid propellant rocket engine has been numerically simulated. The engine has been modeled to operate on a LOX/kerosene mixture at a chamber pressure of 60 bar with 300 kN thrust and kerosene is considered as the coolant. A numerical investigation was performed to determine the effect of different aspect ratio and number of cooling channels on gas-side wall and coolant temperatures and pressure drop in cooling channels.