Statistical Methodology Commons^™

The Evolution Of Reliability Methods For Nondestructive Evaluation (Nde): From Probability Of Detection (Pod) Conception To Contemporary Practices, Christine E. Knott, Jennifer Brown, John Aldrin, Christine M. Schubert Kabban

Faculty Publications

Nondestructive evaluation (NDE) methods are powerful tools for detecting and characterizing flaws in structural components, but their reliability must be evaluated before they can be used in critical applications. For more than 50 years, probabilistic and statistical methods have been used effectively to estimate reliability by describing an NDE system’s Probability of Detection (POD) for flaws of realistic sizes. The POD methods used by the USAF and NASA, like Hit/Miss, Signal-Response (â vs. a), and Point Estimate method (PEM, a.k.a. 29/29) have evolved, alongside newer approaches like Limited Sample POD (LS-POD) method, and Model Assisted Probability of Detection …

Behind The Score: The Influence Of Neighborhood Policy Contexts On New York Regents Exam Performance Across New York City Public High Schools, Philip J. Kovacevic

Dissertations, Theses, and Capstone Projects

This study used a two-level hierarchical linear model (HLM) to test whether New York City neighborhood zoning and land-use characteristics independently predict school-level performance on the New York State Regents Examinations, after controlling for school demographic and organizational characteristics, and Regents mean scores, both drawn from the NYC DOE's Regents Exam Results file (NYC Public Schools InfoHub, 2024). Using NYC Primary Land Use Tax Lot Output (PLUTO) 2025 data, a Neighborhood Educational Quality (NEQ) index was built for each of the city’s 42 community districts by combining the commercial floor area ratio (CommFAR) and the proportion of lots zoned residential …

Predicting Remaining Useful Life Using Multivariate Time-Series Data, Anayah Smith, Victoria Gaibor

Discovery Day - Daytona Beach

Accurate prediction of Remaining Useful Life (RUL) is critical for enabling predictive maintenance, improving system reliability, and reducing operational costs in degrading systems. This project addresses the problem of modeling and predicting RUL using multivariate time-series sensor data from the NASA CMAPSS turbofan engine dataset, with a focus on understanding how predictive performance changes across datasets of varying complexity. The objective is to develop a reproducible machine learning pipeline that captures degradation patterns and produces reliable time-to-failure predictions. The approach includes data preprocessing, exploratory data analysis, feature engineering, dimensionality reduction, and model evaluation. RUL values are computed and capped to …

Modeling Mean And Variability Of Anxiety In Ecological Momentary Assessment Data Using Mixed-Effects Location–Scale Models, Trenzy Odero

Electronic Theses and Dissertations

Ecological Momentary Assessment is a method of collecting repeated measures of people in real time within natural environments. This results in hierarchical data that has a significant amount of variation at the person level. The traditional linear mixedeffects models assume that the residual variance is constant, which might not be true when the residual variance varies among individuals as well as in time. This thesis uses mixed-effects location-scale (MELS) models to model the mean and variance of an EMA outcome together. By introducing the possibility of variability in residual variance within and across individuals and with covariates, the MELS framework …

Volatility Spillovers Between Stock Prices And Exchange Rates: Insights For Risk Management And Investment Strategies: Evidence From China, India, And Pakistan Using Bekk-Garch Models, Samreen Fatima, Humera Sultana, Muhammad Najamuddin Dr., Saba Naz

The Indonesian Capital Market Review

This study investigates the dynamics of volatility and its spillover effects between the stock markets of China, India, and Pakistan, and their respective exchange rates (USD/CNY, USD/INR, and USD/ PKR). Volatility is modeled using the Symmetric and Asymmetric BEKK-GARCH (1,1) and DCCGARCH (1,1) models, based on daily return series covering the period from January 1, 2019, to January 31, 2025. The empirical results indicate that both the employed models are adequate for capturing the volatility dynamics. The findings reveal that the highest value of portfolio weights and hedging efficiency of KSE-100 Index–USD/PKR provide optimal portfolio allocation and highest hedging performance …

Reliability Vs. Validity Visualizer, Manish Rami

Software

A visualization tool to demonstrate the concepts of reliability and validity.

Each target represents repeated measurements of the same person or construct. The crosshair (✛) marks the true score. Reliability = how tightly shots cluster together. Validity = whether shots center on the true score. Click any panel for a clinical SLP example. Also see notes below the plots.

Mengukur Capaian Dan Identifikasi Konvergensi Pembangunan Infrastruktur Antarprovinsi Di Indonesia, Ressa Isnaini Arumnisaa', Aisyah Fitri Yuniasih

Jurnal Ekonomi dan Pembangunan Indonesia

Indonesia’s economic challenges are characterized by stagnant economic growth and regional development disparities. This study analyzes the achievement and convergence of infrastructure development across provinces in Indonesia during 2011–2021 through the construction of an Infrastructure Development Index (IPI). The study employs panel data from 33 provinces, using factor analysis to construct the IPI and the First Difference Generalized Method of Moments (FD-GMM) to examine convergence and its determinants. The results show that many provinces still have IDI scores below the national average. Furthermore, the FD-GMM model shows that σ-convergence and β-convergence occur in Indonesia. In addition, GRDP per capita, inflation, …

Estimasi Underground Economy Triwulanan Di Indonesia Pada Tahun 2010–2023, Ghina Anandhia, Hardius Usman

Jurnal Ekonomi dan Pembangunan Indonesia

Underground economics have a significant impact on economy. Underground economy leads to low potential state revenues from the tax sector. This study estimates the quarterly value of the underground economy in Indonesia from 2010 to 2023 using the Error Correction Model (ECM) method. The results show that the average value of the underground economy in Indonesia is IDR138,392.32 billion, equivalent to 5.36 percent of Gross Domestic Product (GDP) and 35.72 percent of tax revenue from 2010 to 2023. GDP and tax burden variables have a positive influence on currency demand.

Study On Deformation Characteristics Of Kaolin Under Dry-Wet And Freeze-Thaw Cycles, Yang Shang, Xiao Dingyuan

Journal of China & Foreign Highway

In seasonally frozen areas, surface soil is subjected to prolonged and drastic fluctuations in temperature and humidity, causing excessive deformation and resulting in engineering issues such as subgrade settlement and building deformation. The deformation characteristics of kaolin in seasonally frozen areas under the combined influence of freeze-thaw and dry-wet cycles were studied. Through a self-designed experimental setup, experiments with interleaved dry-wet and freeze-thaw cycles were conducted on compacted specimens, and wetting-freezing-thawing-drying cycle experiments were performed to explore the swelling-shrinkage deformation characteristics of kaolin under the combined action of different freeze-thaw and dry-wet cycles. The results indicate that intermittent freeze-thaw cycles …

Material Point Method Simulation Of Soil Landslide Considering Interface Friction Effect, Zuo Zhipeng, Hu Shengliang, Li Maowen, Tong Chenxi, Li Haichao

Journal of China & Foreign Highway

During the high-speed and long-runout sliding failure process of large landslides, severe friction and heat generation in the sliding zone induce an interface friction effect between the debris flow and the bedrock, influencing the final accumulation morphology of the landslide. In this paper, a two-dimensional landslide model of the Yangbaodi landslide in Shenzhen was established using the material point method. A contact algorithm was introduced through a multi-background grid method to conduct numerical simulations on the initiation, sliding, and accumulation processes of the landslide. The results show that after initiation, the landslide moves over a long distance in a flow-like …

Influence Of Geocell Technical Parameters On Bearing Characteristics Of Highway Subgrades In Oasis Areas, Zhu Chunsheng, Shu Xingyu, Lu Huiyu, Yang Xiaohua

Journal of China & Foreign Highway

To study the effects of technical parameters, such as geocell specifications and laying types, on the bearing capacity and deformation of highway subgrades in oasis flood irrigation areas, the shear properties of plain soil and geocell-reinforced layers with different specifications were studied through large-scale direct shear tests. Based on indoor compression tests and field load tests, numerical simulation parameters, such as the deformation modulus of different foundation soil layers, were calibrated. A numerical model of the geocell-reinforced highway subgrade was established using, and the effects of geocell specifications and laying types on the vertical settlement of the subgrade, the displacement …

Stratified Multi-Well Pumping Tests And Back-Analysis Of Hydraulic Conductivity In Ultra-Deep Circular Foundation Pits, Luo Renkun, Wang Jie

Journal of China & Foreign Highway

Dewatering prior to foundation pit excavation is a critical measure to prevent engineering hazards such as slope instability at the pit top, seepage around the pit, and bottom heave. As a key parameter in dewatering design, hydraulic conductivity directly influences the risk control in foundation pit engineering. Based on the east anchor foundation pit project of the Shiziyang Passageway, single-well pumping tests and stratified multi-well pumping tests were conducted. The water level variations in the internal dewatering wells and the external observation wells were monitored in stages. Accordingly, a finite difference numerical model for the pumping tests was established. The …

Study On Effects Of Phase Change Materials On Thermal Erosion Resistance Of Airport Pavement, Li Ping, Li Yunlong, Zheng Zhipeng, Wang Zhijian, Yi Chengxi

Journal of China & Foreign Highway

To investigate the effect of phase change materials (PCMs ) on improving the thermal erosion resistance of airport pavements and to provide recommendations for selecting optimal PCMs to obtain airport pavements with longer service lives, three PCMs, PCM-G- 98 (A), LB- 2 (B), and TH-HC- 120 (C), were purchased based on literature summaries and market research. Based on microscopic test results and the actual preparation conditions of modified asphalt, PCMs A and B were selected. Subsequently, based on a self-made high-content SBS modified asphalt (S), four groups of composite modified asphalts (S-A- 5, S-A- 10, S-B- 5, and S-B- 10) …

Research On Mechanical Properties And Particle Breakage Of Construction Solid Waste Concrete Under Cyclic Loading, Li Xuejian, Song Yang, Dong Chenxi, Li Shengkai, Li Wangyuan

Journal of China & Foreign Highway

To investigate the mechanical properties and particle breakage effect of construction solid waste, a series of static and dynamic direct shear tests were carried out using a dynamic interface shear tester. Different coarse particle contents (40%, 50%, and 60%), amplitudes (45 kPa, 60 kPa, and 75 kPa), and frequencies (0.5 Hz, 1 Hz, and 2 Hz) were used as variables, and the variation rules of shear stress‒shear displacement curves, shear strength parameters, and particle breakage under three normal stresses (50 kPa, 100 kPa, and 150 kPa) were analyzed. The results indicate that under the same initial normal stress, with the …

Study On Influence Of Elastic Modulus Of Fiber On Compaction Characteristics Of Asphalt Mixtures, Zou Zexi, Luo Kaiyan, Lin Zhiming, Qiu Xiang, Lu Xudong, Yao Xiaoyang, Wang Yaolong

Journal of China & Foreign Highway

To investigate the influence mechanism of fiber incorporation on the compaction characteristics of asphalt mixtures, six types of typical road fibers (polyester fiber, polyacrylonitrile fiber, aramid fiber, basalt fiber, polypropylene fiber, and polyvinyl alcohol fiber) were selected in this paper, and gyratory compaction tests were conducted based on AC- 20 graded mixtures. The compaction coefficient (a larger compaction coefficient indicates easier compaction) was used as the core evaluation index. The results indicate that the elastic modulus of the fiber is the key influencing factor. When the fiber modulus is 50% lower than the aggregate modulus (such as polyester fiber and …

Angularity Evaluation Of Coarse Aggregates Based On Local Feature Extraction Of Point Clouds, Ma Quanzhuo, Feng Ponan, Feng Zezhong, Lei Mingyu, Wang Zhenfeng, Li Jiange

Journal of China & Foreign Highway

The morphological characteristics of coarse aggregates significantly affect the mechanical properties of asphalt mixtures and thus directly influence their road performance and durability. This paper aims to innovatively propose an evaluation method for the angularity of coarse aggregates. A three-dimensional (3D) scanner was used to acquire the surface profile information of coarse aggregates, and local angularity features were extracted through point cloud data analysis. Subsequently, a comprehensive 3D angularity evaluation index for coarse aggregates (A3D) was proposed by combining local normal vectors and curvature characteristics. The results indicate that A3D can be more accurately and independently used for angularity evaluation. …

Study On Mechanical Properties Of Ultra-High Performance Concrete With Granite Manufactured Sand After Heating And Cooling Treatment, Li Gang, Zhou Feilong, Lu Qiuju, Du Kun, Liu Kai

Journal of China & Foreign Highway

Due to the frequent occurrence of building fires, the mechanical properties of concrete, as the most widely used construction material, are severely challenged under high temperatures. To explore the effect of granite manufactured sand content on the performance of ultra-high performance concrete (UHPC) after heating and cooling treatment, three types of UHPC specimens with different manufactured sand contents (0, 50%, and 100%) were prepared in this study. Then, the effects of manufactured sand content, heating temperature, and cooling regime on the P-wave velocity and uniaxial compressive strength of UHPC were obtained through experiments. The results indicate that the P-wave velocity …

Characteristic Analysis Of Detection Profiles For Internal Moisture Content Of Asphalt Pavements Based On Ground Penetrating Radar, Yang Li, He Pingping, Liu Weizhen, Fu An

Journal of China & Foreign Highway

As a novel non-destructive testing method for roads, ground penetrating radar (GPR) can effectively prevent road water damage by regularly detecting the internal moisture condition of roads. However, when the moisture data of GPR are analyzed, the moisture conditions obtained by relying solely on the analysis of a single profile characteristic may be misjudged. To improve the accuracy and reliability of GPR in detecting the internal moisture content of pavements, focus was placed on the time-frequency domain analysis of GPR moisture content detection profiles in this paper. Simulation tests were conducted, and the influencing factors and results of moisture detection …

Optimization Design And Experimental Study On Strength Of Ternary Industrial Solid Waste Mixtures, Yang Shu, Ai Yi, Sheng Shanwang, Li Chuangmin

Journal of China & Foreign Highway

This paper aims to explore whether fly ash, lithium slag, and slag powder (ternary industrial solid wastes) can effectively replace cement as cementitious materials for interlocking large-particle crushed stone bases. A uniform design table U9(94) was used to design the test scheme for the mixing ratios of ternary industrial solid waste mixtures; the correlation between the mortar strength and the ternary industrial solid waste mixtures was analyzed by Pearson correlation; with the help of the mathematical statistical software SPSS 26.0, mathematical models for the flexural strength and compressive strength of the ternary industrial solid waste mixture mortar specimens were established. …

Research On Mechanical Properties Of Concrete At High Temperatures Based On Machine Learning, Liu Junhua, Liu Bin, Cao Haifeng, Liu Zhiguang, Li Zhiyong

Journal of China & Foreign Highway

Structural safety is directly affected by the mechanical properties of concrete at high temperatures. Firstly, based on the existing compression and tension test data of concrete at high temperatures, the Abaqus finite element software was adopted for numerical simulation reproduction, and the reliability of the simulation method was verified. Secondly, by simulating the uniaxial tension-compression and confining pressure tests of normal concrete with different strength grades under high temperatures of 20‒800 ℃, the influence rules of temperature on the compressive strength, splitting tensile strength, elastic modulus, and stress ‒ strain relationship of concrete were elucidated. Finally, based on three commonly …