Summation Model Research Articles

Model of spatiotemporal coherent summation of ultra-wideband chaotic radio pulses formed by independent emitters

A model of spatiotemporal summation of ultra-wideband chaotic radio pulses is proposed. The feasibility of using this model for analyzing scenarios of time-coherent radiation from independent sources of ultra-wideband chaotic radio pulses in wireless ultra-wideband systems is substantiated. Two scenarios are considered: where the distance between receiving point and emitters is much greater than the typical size of a group of emitters and where the receiving point is located between the emitters. Distributions of the total pulse energy in space for these scenarios are obtained.

Gender-specific correlations between remnant cholesterol and severe abdominal aortic calcification in American adults.

Remnant cholesterol (RC) predicts cardiovascular risk and is associated with a range of diseases, including asthma, hypertension, depression, periodontitis, and alcoholic fatty liver disease. However, its correlation with abdominal aortic calcification (AAC) has not been reported. Using a cross-sectional approach, this study examined data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) cycle. Multiple logistic regression, generalized summation models, and subgroup analyses were used in examining the correlation between RC and the prevalence of severe AAC. The mean age of participants in this study was 57.70 ± 11.73 years, with 142 individuals (9.67%) suffering from severe AAC. The median RC was 0.52 mmol/L (Q1-Q3, 0.36-0.75 mmol/L). Among female participants, a significant positive correlation was observed between RC and severe AAC (per natural log [RC] increment: 2.14; 95% CI, 1.07-4.27). Smooth curve fitting and threshold effect analysis revealed a saturation effect at an RC level of 0.57 mmol/L. Conversely, in male participants, no significant correlation was found between RC and the prevalence of severe AAC (per natural log [RC] increment: 0.88; 95% CI, 0.43-1.78). Our findings suggest a significant interaction between gender and RC in relation to severe AAC (P for interaction = 0.0042). Higher RC levels were significantly associated with an increased prevalence of severe AAC in women.

Association between City-Level Particulate Matter Exposure and Frailty among Middle-Aged and Older Adults in China

Introduction: The effects of exposure to particulate matter and frailty, as well as its exposure-response relationship, have not been effectively explored. This study aimed to explore the association between long-term exposure to particulate matter and frailty state and each dimension in Chinese middle-aged and older adults, in addition to the exposure-response relationship. Methods: The data were obtained from the National Urban Air Quality Real-Time Dissemination Platform and China Health and Retirement Longitudinal Study (CHARLS). Frailty was measured by a frailty index containing 39 indicators. Annual averages of seven pollutants were calculated from hourly monitoring data. We used multilevel regression modeling to explore the association between long-term exposure to particulate matter and frailty. Meanwhile, we explored the exposure-response relationship based on a multilevel generalized summation model. We performed a sensitivity analysis using a multi-pollution model and a quantile-based g-computation (QGC) model. Results: A total of 15,611 participants were included in the analysis. We find that long-term exposure to PM2.5 was associated with an increased risk of pre-frailty and frailty (all p < 0.05). PMc and PM10 exhibited similar associations. The exposure-response relationship between PM2.5 showed a linear relationship, whereas the exposure-response relationship between PM10, PMc showed a nonlinear relationship. Elevated PM2.5 concentrations showed significant positive associations with the number of chronic disease score, IADL score, and functional limitation status score (all p < 0.05). PM10 and PMc showed similar positive correlations. These results remained robust after sensitivity analyses using a multi-pollution model and QGC model. Conclusion: Chronic exposure to particulate matter was significantly associated with increased risk of frailty. The exposure-response relationship between PM2.5 concentration and frailty showed a linear relationship, and the exposure-response relationship between PM10 and PMc showed a nonlinear relationship. Exposure to a mixture of pollutants carried a higher risk of frailty than exposure to a single pollutant.

RESEARCH OF REPRESENTATIVENESS OF KAZAKH LANGUAGE CORPORA BY WORD STEMS FOR THE SUMMARIZATION

In this work, we investigated the dependence of the work of the summarization model on the number of word stems in it. The work was performed on a synthetic summarization dataset for the Kazakh language. Taking the number of word stems as a metric of representativeness, an analysis of the quality of work of three summation models was performed depending on the number of word stems in the training dataset. To obtain three datasets, we divided the training dataset into three parts. BLEU estimates were obtained for each model on the test files. The experimental part of the work showed that the model with the largest number of stems shows the highest BLEU score. But the score does not directly depend on the number of word stems. Two models trained on datasets of different sizes show approximately the same scores.

Association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) and sleep disorders in US adults: NHANES 2005 to 2016.

NHHR (non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio) is a novel lipid parameter. However, the association between NHHR and sleep disorders remains unknown.; A cross-sectional analysis was conducted using data from the National Health and Nutrition Examination Survey (NHANES) 2005 to 2016. The association between NHHR and sleep disorders was explored using weighted multivariate logistic regression and generalized summation models. Subgroup analyses were employed to verify the robustness of this association. The prevalence of sleep disorders was 25.83% in a total of 22,221 participants. Compared to the lowest quartile of NHHR, participants in the top quartile had a 14% higher odds of sleep disorders prevalence in fully adjusted model (OR: 1.14, 95% CI: 1.06-1.23). After subgroup analyses and interaction tests, sex, race, marital status, education level, body mass index (BMI), person income ratio (PIR), alcohol consumption, smoking status, hypertension, and diabetes mellitus were not significantly associated with this positive association (P for interaction > 0.05). The NHHR is positively associated with sleep disorders in US adults. The management and monitoring of NHHR may have a potential role in improving sleep disorders.

Different secure semi-quantum summation models without measurement

Secure semi-quantum summation entails the collective computation of the sum of private secrets by multi-untrustworthy and resource-limited participants, facilitated by a quantum third-party. This paper introduces three semi-quantum summation protocols based on single photons, where eliminating the need for classical users to possess measurement capabilities. Two-party protocol 1 and protocol 2 are structured upon different models: star and ring, respectively. The security analysis extensively evaluates the protocols’ resilience against outside and inside attacks, demonstrating protocols are asymptotically secure. Protocol 3 extends two-party protocol 1 to multi-party scenarios, broadening its applicability. Comparison reveals a reduction in the workload for classical users compared to previous similar protocols, and the protocols’ correctness are visually validated through simulation by Qiskit.

Estimation of fracture behavior of CFRP/CFRP adhesively bonded joints under mixed-mode conditions using a cohesive zone model

Finite element (FE) simulations of adhesively bonded composite joints were conducted using the cohesive zone model (CZM). To clarify the effect of fracture criteria on the accuracy of the CZM simulation, two types of mixed-mode criteria including the ­linear summation model of Modes I and II energy release rates, G I / G IC + G II / G IIC = 1 , and the nonlinear power-law, ( G I / G IC ) n + ( G II / G IIC ) n = 1 , were employed. A CZM formulation using the power-law fracture criterion was developed in this study. The load–displacement curves calculated by the two models were compared with the experimental results obtained from mixed-mode Fernlund–Spelt-type double cantilever beam tests, and the Mode II end-notched flexure (ENF) tests. Calculations using the nonlinear fracture criterion were closer to the experimental results. Consequently, it is concluded that nonlinear fracture modeling is of vital importance for accurate strength analysis of mixed-mode adhesive joints.

Multisensory-inspired modeling and neural correlates for two key binocular interactions

Most binocular vision models assume that the two eyes sum incompletely. However, some facilitatory cortical neurons fire for only one eye, but amplify their firing rates if both eyes are stimulated. These ‘binocular gate’ neurons closely resemble subthreshold multisensory neurons. Binocular amplification for binocular gate neurons follows a power law, with a compressive exponent. Unexpectedly, this rule also applies to facilitatory true binocular neurons; although driven by either eye, binocular neurons are well modeled as gated amplifiers of their strongest monocular response, if both eyes are stimulated. Psychophysical data follows the same power law as the neural data, with a similar exponent; binocular contrast sensitivity can be modeled as a gated amplification of the more sensitive eye. These results resemble gated amplification phenomena in multisensory integration, and other non-driving modulatory interactions that affect sensory processing. Models of incomplete summation seem unnecessary for V1 facilitatory neurons or contrast sensitivity. However, binocular combination of clearly visible monocular stimuli follows Schrödinger’s nonlinear magnitude-weighted average. We find that putatively suppressive binocular neurons closely follow Schrödinger’s equation. Similar suppressive multisensory neurons are well documented but seldom studied. Facilitatory binocular neurons and mildly suppressive binocular neurons are likely neural correlates of binocular sensitivity and binocular appearance respectively.

Summative Evaluation Model of Slum Treatment in Kendari City, Southeast Sulawesi, Indonesia

Summative Evaluation Model of Slum Treatment in Kendari City, Southeast Sulawesi, Indonesia

Stability analysis of discrete-time systems with arbitrary delay kernels based on kernel-related summation inequality and model transformation

In the existing papers considering the stability analysis of discrete-time systems with distributed delays via the Lyapunov-Krasovskii functional (LKF) method, the delay kernels are normally restricted to be non-negative. In this paper, we aim to remove such a restriction and deal with the stability analysis of systems with arbitrary delay kernels. For this purpose, a kernel-related summation inequality is first constructed. Then, a stability condition is derived based on the proposed inequality and a model transformation. Finally, two numerical examples are presented to show that the proposed stability condition not only has a wider scope of application and is less conservative than the existing ones.

Research on dynamic stability of rolling missiles employing direct/aerodynamic force compound control

The direct/aerodynamic force compound control can enhance the maneuverability and response characteristics of missiles, and the dynamic stabilization is the precondition of normal operation for rolling missiles. Aiming at the stability problem caused by the cross-coupling effect of rolling missiles employing direct/aerodynamic force compound control, proposing a typical topological control system structure described by the complex coefficient theory, and deducing the dynamic stability conditions. Firstly, the mathematic model is established based on the kinematics and dynamics theories of rotating airframes and the direct/aerodynamic force compound control mechanism. Then, a three-loop autopilot and the direct/aerodynamic force ratio distribution method are designed to establish the complex summation model of the compound control system by selecting suitable complex variables. Furthermore, deducing the dynamic stability conditions and verifying them by numerical simulations. Finally, the stable regions of the rolling missile in different cases are obtained and found to be influenced by many factors, such as parameters of the autopilot, hybrid force distribution proportion and rolling rate. The derived dynamic stability criterion is effective for evaluating the stability of rolling missiles employing direct/aerodynamic force compound control and the research method used in this paper can provide reference for the stability study of strongly coupled nonlinear systems.

Global Cardiovascular Risk and Associated Factors in 2792 French Military and Civilian Aircrew.

INTRODUCTION: Cardiovascular (CV) diseases are a major public health issue, the prevention of which plays a key role in promoting flight safety. However, few studies have looked at the determinants of the overall risk of CV morbidity-mortality within the various aeronautical occupations.METHODS: A monocentric, observational, cross-sectional study was based on the retrospective data collected during 6 mo at the Toulon Aeromedical Center. From October 2017 to April 2018, 2792 professional aircrew ages 18-74 were included. The overall CV risk was estimated using the European Society of Cardiology SCORE and the Framingham model, as well as a summation model.RESULTS: More than two-thirds of this mainly male population (86.2%) had no more than one CV risk factor [69.9% (68.2-71.6)]. In 82.5% of cases, this was dyslipidemia according to current European criteria [55.8% (52.4-59.1)] or smoking [26.7% (23.8-29.8)]. An overall risk level of "moderate" to "very high" concerned only one subject in five according to the SCORE model [20.1% (18.6-21.6)], one in six according to Framingham [16.3% (14.9-17.7)] and almost one in three according to the summation model [30.1% (28.4-31.9)].DISCUSSION: Multivariate analyses found no significant associations between socio-professional criteria and overall risk levels. The results have underlined the effect of dyslipidemia and smoking on early risk among applicants. Beyond the illustration of favorable cardiovascular status among aircrews related to the standards of selection and close monitoring process, areas for improvement were identified, inviting the development of prevention strategies around the "moderate" overall CV risk.Huiban N, Gehant M, Brocq F-X, Collange F, Mayet A, Monteil M. Global cardiovascular risk and associated factors in 2792 French military and civilian aircrew. Aerosp Med Hum Perform. 2024; 95(5):233-244.

A Review of Cross-Scale Theoretical Contact Models for Bolted Joints Interfaces

Bolted joints structures are critical fastening components widely used in mechanical equipment. Under long-term loading conditions, the bolted joints interface generates strong nonlinearities within the system. The nonlinear stiffness inside the bolt leads to changes in the stiffness of the whole system. This affects the dynamic characteristics of the whole system. It brings challenges and difficulties to the performance prediction and reliability assessment of the equipment. A cross-scale theoretical model study based on the microscopic contact mechanism can provide a more comprehensive understanding and cognition of the degradation behavior of bolted joints interfaces. The current development status and deformation process of asperity models are summarized. The research progress of statistical summation model and contact fractal model based on microscopic contact mechanism is analyzed. The experimental methods for parameter identification of connection interfaces are reviewed. The study of numerical modelling of bolted joints structures from the surface contact mechanism is briefly described. Future research directions for cross-scale modelling of bolted joints structures are outlined.

Development of high-speed algorithm for binomial arithmetic addition

The object of research is the method and algorithm of arithmetic addition of binomial numbers generated by binary binomial counting systems. The lack of binomial arithmetic, in particular the operation of adding binary binomial numbers, in a certain way prevents their introduction into information systems and the construction of information and communication technologies based on them for combinatorial optimization, generation of combinatorial objects, data compression and encryption. In the framework of the proposed approach, instead of operating with binomial coefficients, only operations with their upper and lower parameters are carried out. At the same time, the weighting coefficients of binary binomial numbers, which are added to each other, are represented in the form of two-component tuples. Taking this into account, this paper presents an algorithm for binomial arithmetic addition using dynamic arrays. The main idea, which is included in the structure of the algorithm of binomial arithmetic addition based on dynamic arrays, is that the transition from a two-dimensional model of summation to a one-dimensional one is carried out. At the same time, only available, existing binomial coefficients are placed in the dynamic array. Accordingly, the search for binomial coefficients equal to or greater than the quantitative equivalent takes place in much smaller areas. In comparison with the algorithm based on matrix models, this quite significantly reduces the amount of time spent when performing the summation operation, and also reduces the requirements for the amount of memory required for placing two-component tuples of the assembly array. In the course of the research, a several-fold decrease in the number of machine cycles required to search for the necessary elements in the dynamic array was practically confirmed. This leads to an increase in the performance of the presented algorithm of binomial arithmetic addition based on dynamic arrays. In turn, this leads to the acceleration of solving information tasks of combinatorial optimization, generation of combinatorial objects, data compression and encryption, for the solution of which the operation of adding binary binomial numbers is used.

New Summation and Integral Representations for 2-Variable (p,q)-Hermite Polynomials

In this paper, we introduce and study new features for 2-variable (p,q)-Hermite polynomials, such as the (p,q)-diffusion equation, (p,q)-differential formula and integral representations. In addition, we establish some summation models and their (p,q)-derivatives. Certain parting remarks and nontrivial examples are also provided.

Interrupted mosaic speech revisited: Gain and loss in intelligibility by stretchinga).

Our previous investigation on the effect of stretching spectrotemporally degraded and temporally interrupted speech stimuli showed remarkable intelligibility gains [Udea, Takeichi, and Wakamiya (2022). J. Acoust. Soc. Am. 152(2), 970-980]. In this previous study, however, gap durations and temporal resolution were confounded. In the current investigation, we therefore observed the intelligibility of so-called mosaic speech while dissociating the effects of interruption and temporal resolution. The intelligibility of mosaic speech (20 frequency bands and 20 ms segment duration) declined from 95% to 78% and 33% by interrupting it with 20 and 80 ms gaps. Intelligibility improved, however, to 92% and 54% (14% and 21% gains for 20 and 80 ms gaps, respectively) by stretching mosaic segments to fill silent gaps (n = 21). By contrast, the intelligibility was impoverished to a minimum of 9% (7% loss) when stretching stimuli interrupted with 160 ms gaps. Explanations based on auditory grouping, modulation unmasking, or phonemic restoration may account for the intelligibility improvement by stretching, but not for the loss. The probability summation model accounted for "U"-shaped intelligibility curves and the gain and loss of intelligibility, suggesting that perceptual unit length and speech rate may affect the intelligibility of spectrotemporally degraded speech stimuli.

A signal-detection account of item-based and ensemble-based visual change detection: A reply to Harrison, McMaster, and Bays.

Growing empirical evidence shows that ensemble information (e.g., the average feature or feature variance of a set of objects) affects visual working memory for individual items. Recently, Harrison, McMaster, and Bays (2021) used a change detection task to test whether observers explicitly rely on ensemble representations to improve their memory for individual objects. They found that sensitivity to simultaneous changes in all memorized items (which also globally changed set summary statistics) rarely exceeded a level predicted by the so-called optimal summation model within the signal-detection framework. This model implies simple integration of evidence for change from all individual items and no additional evidence coming from ensemble. Here, we argue that performance at the level of optimal summation does not rule out the use of ensemble information. First, in two experiments, we show that, even if evidence from only one item is available at test, the statistics of the whole memory set affect performance. Second, we argue that optimal summation itself can be conceptually interpreted as one of the strategies of holistic, ensemble-based decision. We also redefine the reference level for the item-based strategy as the so-called "minimum rule," which predicts performance far below the optimum. We found that that both our and Harrison et al. (2021)'s observers consistently outperformed this level. We conclude that observers can rely on ensemble information when performing visual change detection. Overall, our work clarifies and refines the use of signal-detection analysis in measuring and modeling working memory.

Improving accuracy of age estimates for insect evidence-calibration of physiological age at emergence (k) using insect size but without "k versus size" model.

Postmortem interval may be estimated based on the age of insect evidence collected on a death scene. Reference data that are used in such estimation frequently comprise thermal summation constant (i.e. k), which is equal to the insect age upon completion of immature development expressed in accumulated degree-days or degree-hours (ADD or ADH). Essentially, k is a central point of an insect group and it may poorly represent insect evidence that is near the limits of variation for the group. Accordingly, it was postulated to calibrate k for particular insect evidence and insect size and sex were found to be useful for this purpose in some of the species. However, the calibration is only possible by using the model that correlates k with insect size. Since very few such models were published, this lack of data limits the calibration of k in forensic casework. In this article, we develop a formula that is useful for the calibration of k without the use of "k versus size" model (and related datasets). The formula uses k from the general thermal summation model for a species (with its standard error), size range for the species (retrieved from entomology literature), and size measurements for particular insect evidence. The calibration of k with the formula was validated using the Creophilus maxillosus (Coleoptera: Staphylinidae) and Necrodes littoralis (Coleoptera: Silphidae) datasets. It was particularly useful while analyzing unusually small and large insects, in case of which the formula reduced the inaccuracy of k from the general model on average by ~25 ADD in C. maxillosus and ~40 ADD in N. littoralis. We discuss the limitations and prospects of the calibration protocol that employs the formula.

Association between triglyceride glucose index and all-cause mortality in patients with cerebrovascular disease: a retrospective study

BackgroundTriglyceride glucose (TyG) is associated with stroke, atherosclerosis, and adverse clinical outcomes. However, its correlation with cerebrovascular disease (CVD) mortality remains unclear. This study aimed to investigate the relationship between TyG index and mortality in patients with CVD.MethodsPatient data sourced from the Medical Information Mart for Intensive Care -IV database were categorized based on TyG quartiles. Kaplan–Meier survival analysis was used to estimate survival disparities among the TyG subgroups. Cox proportional risk modeling was used to examine the association between the TyG index and mortality. Generalized summation models were applied to fit the smoothed curves. log-likelihood ratio test were used to analyze the non-linear relationship.ResultsThe study comprised 1,965 patients (50.18% were male). The 28-day and 90-day mortality rates were 20.10% and 24.48%, respectively. The TyG index exhibited a linear relationship with the 28-day mortality (Hazards ratio (HR), 1.16; 95% confidence interval (CI), 0.99–1.36) and the 90-day mortality (HR, 1.18; 95% CI, 1.02–1.37). In the TyG Q4 group, each 1 mg/dl increase was linked to a 35% rise in the risk of 28-day mortality and a 38% increase in the risk of 90-day mortality. Subgroup analyses highlighted a more substantial association between TyG index and 90-day mortality in the diabetic group.ConclusionOur findings underscore the positive association between TyG and the 28- and 90-day mortality rates in patients with CVD. This insight may prove pivotal for identifying at-risk populations and enhancing risk prediction in the clinical management of CVD.

Are Fatigue and Sleepiness the Same? A Brief Introduction to the Differences and Similarities and Their Implications for Work Safety.

Fatigue-related risk is a persistent safety concern for the mining industry. However, fatigue and sleepiness are often treated interchangeably, which can lead to confusion and potentially less effective reduction of safety risk. To provide clarity, we present an overview of similarities and differences between work-related fatigue risk and sleepiness including definitions, theories, measurements, and mitigation strategies. As a supplement, a summative visual model which highlights these similarities and differences is presented. Expanding industry knowledge in this area will assist safety professionals in crafting more targeted risk management practices appropriate for work-related fatigue risk, sleepiness, or both.