STATISTICAL INTERVALS FOR VARIOUS DISTRIBUTIONS BASED ON DIFFERENT INFERENCE METHODS

Statistical intervals (e.g., confidence, prediction, or tolerance) are widely used to quantify uncertainty, but complex settings can create challenges to obtain such intervals that possess the desired properties. My thesis will address diverse data settings and approaches that are shown empirically to have good performance. We first introduce a focused treatment on using a single-layer bootstrap calibration to improve the coverage probabilities of two-sided parametric tolerance intervals for non-normal distributions. We then turn to zero-inflated data, which are commonly found in, among other areas, pharmaceutical and quality control applications. However, the inference problem often becomes difficult in the presence of excess zeros. When data are semicontinuous, the log-normal and gamma distributions are often considered for modeling the positive part of the model. The problems of constructing a confidence interval for the mean and calculating an upper tolerance limit of a zero-inflated gamma population are considered using generalized fiducial inference. Furthermore, we use generalized fiducial inference on the problem of constructing confidence intervals for the population mean of zero-inflated Poisson distribution. Birnbaum–Saunders distribution is widely used as a failure time distribution in reliability applications to model failure times. Statistical intervals for Birnbaum–Saunders distribution are not well developed. Moreover, we utilize generalized fiducial inference to obtain the upper prediction limit and upper tolerance limit for Birnbaum–Saunders distribution. Simulation studies and real data examples are used to illustrate the effectiveness of the proposed methods

Generalized Fiducial Inference on the Mean of Zero-Inflated Poisson and Poisson Hurdle Models

Zero-inflated and hurdle models are widely applied to count data possessing excess zeros, where they can simultaneously model the process from how the zeros were generated and potentially help mitigate the effects of overdispersion relative to the assumed count distribution. Which model to use depends on how the zeros are generated: zero-inflated models add an additional probability mass on zero, while hurdle models are two-part models comprised of a degenerate distribution for the zeros and a zero-truncated distribution. Developing confidence intervals for such models is challenging since no closed-form function is available to calculate the mean. In this study, generalized fiducial inference is used to construct confidence intervals for the means of zero-inflated Poisson and Poisson hurdle models. The proposed methods are assessed by an intensive simulation study. An illustrative example demonstrates the inference methods

Using Medical Claims Database to Develop a Population Disease Progression Model for Leuprorelin-Treated Subjects with Hormone-Sensitive Prostate Cancer

Androgen deprivation therapy (ADT) is a widely used treatment for patients with hormone-sensitive prostate cancer (PCa). However, duration of treatment response varies, and most patients eventually experience disease progression despite treatment. Leuprorelin is a luteinizing hormone-releasing hormone (LHRH) agonist, a commonly used form of ADT. Prostate-specific antigen (PSA) is a biomarker for monitoring disease progression and predicting treatment response and survival in PCa. However, time-dependent profile of tumor regression and growth in patients with hormone-sensitive PCa on ADT has never been fully characterized. In this analysis, nationwide medical claims database provided by Humana from 2007 to 2011 was used to construct a population-based disease progression model for patients with hormone-sensitive PCa on leuprorelin. Data were analyzed by nonlinear mixed effects modeling utilizing Monte Carlo Parametric Expectation Maximization (MCPEM) method in NONMEM. Covariate selection was performed using a modified Wald’s approximation method with backward elimination (WAM-BE) proposed by our group. 1113 PSA observations from 264 subjects with malignant PCa were used for model development. PSA kinetics were well described by the final covariate model. Model parameters were well estimated, but large between-patient variability was observed. Hemoglobin significantly affected proportion of drug-resistant cells in the original tumor, while baseline PSA and antiandrogen use significantly affected treatment effect on drug-sensitive PCa cells (Ds). Population estimate of Ds was 3.78 x 10−2 day-1. Population estimates of growth rates for drug-sensitive (Gs) and drug-resistant PCa cells (GR) were 1.96 x 10−3 and 6.54 x 10−4 day-1, corresponding to a PSA doubling time of 354 and 1060 days, respectively. Proportion of the original PCa cells inherently resistant to treatment was estimated to be 1.94%. Application of population-based disease progression model to clinical data allowed characterization of tumor resistant patterns and growth/regression rates that enhances our understanding of how PCa responds to ADT

Evidence of spin density waves in La3_3Ni2_2O7−δ_{7-\delta}

The recently discovered superconductivity with critical temperature $T_{c}$ up to 80 K in the Ruddlesden-Popper phases La$_3$Ni$_2$O$_{7-\delta}$ under pressure has drawn great attention. Here we report the positive muon spin relaxation ($\mu^+$SR) study of polycrystalline La$_3$Ni$_2$O$_{7-\delta}$ under ambient pressure. The zero-field $\mu^+$SR experiments reveal the existence of static long range magnetic order in La$_3$Ni$_2$O$_{7-\delta}$, and the the muon spin depolarization spectra are consistent with the spin density wave internal field distribution. The weak transverse field $\mu^+$SR measurements suggest the bulk magnetic transition near $T_{\rm{N}}=148$ K. This is the first research which discovers the existence of the spin density wave in La$_3$Ni$_2$O$_{7-\delta}$ microscopically

Few-photon single ionization of cold rubidium in the over-the-barrier regime

Photoionization of the rubidium (Rb) atoms cooled in a magneto-optical trap, characterized by the coexistence of the ground 5$S_{1/2}$ and the excited 5$P_{3/2}$ states, is investigated experimentally and theoretically with the 400 nm femtosecond laser pulses at intensities of $I=3\times10^9$ W/cm$^2$ - $4.5\times10^{12}$ W/cm$^2$. Recoil-ion momentum distribution (RIMD) of Rb$^+$ exhibits rich ring-like structures and their energies correspond to one-photon ionization of the 5$P_{3/2}$ state, two-photon and three-photon ionizations of the 5$S_{1/2}$ state, respectively. With the increasing of $I$, we find that experimental signals near zero-momentum (NZM) in RIMDs resulted from the 5$P_{3/2}$ state enhance dramatically and its peaked Rb$^+$ momenta dwindle obviously while that from the 5$S_{1/2}$ state is maintained. Meanwhile, the ion-yield ratio of the 5$S_{1/2}$ over the 5$P_{3/2}$ states varies from $I$ to $I^{1.5}$ as $I$ increases. These features indicate a transition from perturbative ionization to strong-perturbative ionization for the 5$P_{3/2}$ state. Numerical simulations by solving the time-dependent Schr\"odinger equation (TDSE) can qualitatively explain the measurements of RIMD, photoion angular distributions, as well as ion-yield ratio. However, some discrepancies still exist, especially for the NZM dip, which could stem from the electron-electron correlation that is neglected in the present TDSE simulations since we have adopted the single-active-electron approximation

Undergraduates' perceptions on emergency remote learning in ecology in the post‐pandemic era

The COVID-19 pandemic has strongly disrupted academic activities, particularly in disciplines with a strong empirical component among other reasons by limiting our mobility. It is thus essential to assess emergency remote teaching plans by surveying learners’ opinions and perceptions during these unusual circumstances. To achieve this aim, we conducted a survey during the spring semester of 2021 in an environmental science program to ascertain learners’ perceptions on online and onsite learning activities in ecology-based modules. We were particularly interested not only in comparing the performance of these two types of activities but also in understanding the role played by learners’ perceptions about nature in shaping this pattern. Environmental science programs are rather heterogeneous from a conceptual point of view and, thus, learners may also be more diverse than in traditional ecology programs, which may affect their interest for ecology-based modules. We assessed connectedness to nature by computing the reduced version of the Nature Relatedness Scale. Here, we found that online activities systematically obtained significantly lower scores than onsite activities regardless of the wording employed, and that altruistic behaviors were prevalent among learners. Interestingly, scores for both onsite and online activities were strongly influenced by learners’ connectedness to nature, as learners with a stronger connection to nature gave higher scores to both types of activities. Our results suggest that an effort to improve the efficacy of remote learning activities should be the focus of research about teaching methodologies in predominantly empirical scientific disciplines

A Critical Review of Laser Shock Peening of Aircraft Engine Components

Article describes how many aviation accidents are caused by the failure of aircraft engine components, and engine blades are especially vulnerable to high-cycle fatigue fracture in severe working environments as well as to impact damage caused by foreign objects. This review provides an overview of the development of LSP for use in treating aircraft engine components over the past three decades, with a brief introduction to the development of high-energy pulsed lasers for LSP

Pragmatic Functions of Move Structures in Online Chinese Hotel Complaint Responses

The paper employs genre analysis to investigate the pragmatic functions of complaint responses of five-star hotels in China. The study first summarizes the move structures of complaint responses at the macro level and then explores the realization process of the main moves on the communicative purpose. Based on previous studies and data analysis, there are four moves and fourteen sub-moves in complaint responses. Grounding the theoretical framework of rapport management, the study identifies the relation-oriented, task-oriented, and promotion-oriented functions of moves in Chinese hotel complaint responses. Besides, this paper compares the differences between various functions to summarize the response strategies suitable for Chinese hotels. Overall, the present study sets up a more comprehensive move framework of online business complaint responses, which can help to strengthen the interpretation of consumer complaints and provide references for enhancing customer satisfaction and maintaining a harmonious relationship with customers

Influencing Factors and Measures of Users’ Privacy Disclosure in Social E-commerce

This paper integrates Utility Theory and Communication Privacy Management Theory to explore the influencing factors of privacy disclosure in social e-commerce scenarios. The aim of this research is to provide references to optimize service for platform operators and encourage users to participate in content creation. Social e-commerce websites are the platforms based on social networking. It shortens the distance with consumers and promote e-commerce transaction activities. However, the leakage of personal privacy on the platform has cracked down on the willingness of users to disclose information. This paper collects sample data through questionnaire survey for analysis. Based on users’ psychology, suggestions are given on upgrading data encryption technology to strengthen platform image marketing and give information management rights to users. It is found that perceived revenue, perceived information control and trust stimulate users’ privacy disclosure, while perceived risk suppresses user’s privacy disclosure in social e-commerce website

The Influence of E-learning Behavior on Students’ Learning Performance of Disaster Emergency Knowledge

E-learning has advantages of huge learning resources, enthusiastic learners, friendly interaction and flexible space-time, especially, the large-scale application of many new educational technologies makes e-learning possible. Based on the theory of deconstruction program behavior and task technology fit model, four assumptions of e-learning behavior’s influence on learning performance of students’ disaster emergency knowledge were put forward from two aspects, namely the individual factors (self-efficacy), information literacy and environmental factors (technical characteristics, and promote conditions), the PLS (partial least squares) method was used to carry out regression analysis of affecting factors. Results show that the Cronbach’s ɑ values of the questionnaire are all greater than 0.8, indicating that the measurement indexes have high reliability. AVE (average variance extracted) values of all latent variables are greater than the threshold level of 0.5, showing good aggregation validity. The square root of AVE value is greater than correlation coefficient of each latent variable, and the discrimination validity is good. Information literacy, technical characteristics and facilitation conditions have a positive and significant impact on learning performance of students adopting e-learning of disaster emergency knowledge. The conclusions provide practical suggestions and opinions for enriching the analysis of learning behavior under the e-learning environment, depicting the characteristics of students’ e-learning behavior