State space modeling of autocorrelated multivariate Poisson counts

<p>Although many applications involve autocorrelated multivariate counts, there is a scarcity of research on their statistical modeling. To fill this research gap, this article proposes a state space model to describe autocorrelated multivariate counts. The model builds upon the multivariate log-normal mixture Poisson distribution and allows for serial correlations by considering the Poisson mean vector as a latent process driven by a nonlinear autoregressive model. In this way, the model allows for flexible cross-correlation and autocorrelation structures of count data and can also capture overdispersion. The Monte Carlo Expectation Maximization algorithm, together with particle filtering and smoothing methods, provides satisfactory estimators for the model parameters and the latent process variables. Numerical studies show that, compared with other state-of-the-art models, the proposed model has superiority and more generality with respect to describing count data generated from different mechanisms of the process of counts. Finally, we use this model to analyze counts of different types of damage collected from a power utility system as a case study. Supplementary materials are available for this article. Go to the publisher’s online edition of <i>IISE Transactions</i> for additional tables and figures.</p

Tailoring the Transport Properties of Zeolitic Imidazolate Frameworks by Post-Synthetic Thermal Modification

Understanding how to control transport properties of zeolitic imidazolate frameworks (ZIFs) is critical to extend ZIF-based membranes and adsorbents to a wide spectrum of gas and vapor separations. In this work, we report a facile post-synthetic thermal modification (PSTM) technique to tailor ZIFs’ transport properties by balancing diffusivity and diffusion selectivity. With controllable dissociation of framework methyl groups from a precursor ZIF (ZIF-8), we have prepared thermally modified ZIFs showing substantially increased <i>n</i>-butane diffusivity and attractive <i>n</i>/<i>iso</i>-butane diffusion selectivity. Hybrid ZIF/polymer mixed-matrix membranes formed using these thermally modified ZIFs are expected to deliver attractive butane isomer separation performance. Membranes based on such materials can potentially be used to retrofit refinery alkylation units for producing premium gasoline blending stocks

A Bayesian Partially Observable Online Change Detection Approach with Thompson Sampling

This paper proposes a Bayesian learning framework for online change detection of high-dimensional data streams where only a subset of variables can be observed at each time point due to limited sensing capacities. On the one hand, we need to build a change detection scheme based on partial observations. On the other, the scheme should be able to adaptively and actively select the most critical sensing variables to observe to maximize the detection power. To address these two points, in this paper, first, a novel Bayesian Spike-Slab Composite Decomposition (BSSCD) is proposed to decompose the high-dimensional signals onto normal and abnormal bases, where the projection coefficients are efficiently estimated via variational Bayesian inference. Built upon it, the posterior Bayes factor is constructed as the detection statistic. Second, by further formulating it as the reward function of combinatorial multi-armed bandit (CMAB), a Thompson sampling strategy is proposed for selecting the potential changed variables with the balance of exploration and exploitation. The efficacy and applicability of our method are demonstrated in practice with numerical studies and a real case study.</p

Longitudinal-torsional complex-mode ultrasonic actuator for vibration-assisted drilling of CFRP

Carbon-fiber-reinforced plastic (CFRP) composites are intensively used in aircraft and aerospace industry thanks to their superior properties. Comparing to the conventional drilling (CD), vibration-assisted drilling (VAD) is a novel machining technique suitable for drilling CFRP. Still, multi-mode excitations with elliptical locus and low vibration performance limit the applications of current VAD schemes for CFRP. To overcome these limitations and improve the overall performance, an innovative longitudinal-torsional complex-mode ultrasonic vibration-assisted actuator with single excitation and an elliptical locus is presented employing a piezoelectric transducer and a stepped horn with spiral grooves. The proposed actuator is specially designed to deliver elliptical vibration and assure high vibration performance of a tool tip. Analysis of the actuation mechanism for the longitudinal-torsional composite vibration mode is discussed, and its simplified model is developed. A detailed design process of this actuator is given. Its vibration characteristics are verified with both finite-element simulation and experimental modal analysis using a swept sine test. It is demonstrated the developed prototype achieved longitudinal-torsional elliptical vibration. To validate the machining performance of the actuator, two groups of drilling experiments were performed. These indicate that the proposed actuator is capable of drilling CFRP with improved machining performance

Image_1_The framework and features of language policies in global constitutional texts.TIF

Language policy, which is directly concerned with language practice, language ideology and language management, has become increasingly important in real social life. Explicit language policies in different fields, such as texts in law, education, and the public, have been explored for many years. However, the global comparative research on language policies in various constitutional texts (CT) is quite limited. In response, the present study aimed to investigate the framework and features of language policies in global CT through a combination of qualitative and quantitative analysis. Results showed that: 1) there were seven parts of the CT dealing with language policies, such as Preamble, General principle, The state, Fundamental rights and Duties of citizen, State authority, National objectives, and Supplementary; 2) there existed significant differences in the frequency of language policies in seven parts of the CT. Among them, language policies appeared most frequently in the part of Fundamental rights and duties of citizen; 3) the geographical location where the Constitution was enacted affected the distribution of language policies across parts. Overall, our findings suggested that the language policy in CT was influenced not only by constitutional principles, but also by the national language environment.</p

Table_1_The framework and features of language policies in global constitutional texts.XLSX

Language policy, which is directly concerned with language practice, language ideology and language management, has become increasingly important in real social life. Explicit language policies in different fields, such as texts in law, education, and the public, have been explored for many years. However, the global comparative research on language policies in various constitutional texts (CT) is quite limited. In response, the present study aimed to investigate the framework and features of language policies in global CT through a combination of qualitative and quantitative analysis. Results showed that: 1) there were seven parts of the CT dealing with language policies, such as Preamble, General principle, The state, Fundamental rights and Duties of citizen, State authority, National objectives, and Supplementary; 2) there existed significant differences in the frequency of language policies in seven parts of the CT. Among them, language policies appeared most frequently in the part of Fundamental rights and duties of citizen; 3) the geographical location where the Constitution was enacted affected the distribution of language policies across parts. Overall, our findings suggested that the language policy in CT was influenced not only by constitutional principles, but also by the national language environment.</p

Weakly correlated profile monitoring based on sparse multi-channel functional principal component analysis

<p>Although several works have been proposed for multi-channel profile monitoring, two additional challenges are yet to be addressed: (i) how to model complex correlations of multi-channel profiles when different profiles have different features (i.e., weakly or sparsely correlated); (ii) how to efficiently detect sparse changes occurring in only a small segment of a few profiles. To fill this research gap, our contributions are twofold. First, we propose a novel Sparse Multi-channel Functional Principal Component Analysis (SMFPCA) to model multi-channel profiles. SMFPCA can not only flexibly describe the correlation structure of multiple, or even high-dimensional, profiles with distinct features, but also achieve sparse PCA scores which are easily interpretable. Second, we propose an efficient convergence-guaranteed optimization algorithm to solve SMFPCA in real time based on the block coordinate descent algorithm. Third, as the SMFPCA scores can naturally identify sparse out-of-control (OC) patterns, we use the scores to construct a monitoring scheme which provides increased sensitivity to sparse OC changes. Numerical studies together with a real case study in a manufacturing system demonstrate the effectiveness of the developed methodology.</p

Quantitative Shotgun Proteomics Associates Molecular-Level Cadmium Toxicity Responses with Compromised Growth and Reproduction in a Marine Copepod under Multigenerational Exposure

In this study, the copepod <i>Tigriopus japonicus</i> was exposed to different cadmium (Cd) treatments (0, 2.5, 5, 10, and 50 μg/L in seawater) for five generations (F0–F4), followed by a two-generation (F5–F6) recovery period in clean seawater. Six life-history traits (survival, developmental time of nauplius phase, developmental time to maturation, number of clutches, number of nauplii/clutch, and fecundity) were examined for each generation. Metal accumulation was also analyzed for generations F0–F6. Additionally, proteome profiling was performed for the control and 50 μg/L Cd-treated F4 copepods. In F0–F4 copepods, Cd accumulated in a concentration-dependent manner, prolonging the development of the nauplius phase and maturation and reducing the number of nauplii/clutch and fecundity. However, during F5–F6, Cd accumulation decreased rapidly, and significant but subtle effects on growth and reproduction were observed only for the highest metal treatment at F5. Proteomic analysis revealed that Cd treatment had several toxic effects including depressed nutrient absorption, dysfunction in cellular redox homeostasis and metabolism, and oxidative stress, resulting in growth retardation and reproduction limitation in this copepod species. Taken together, our results demonstrate the relationship between molecular toxicity responses and population-level adverse outcomes in <i>T. japonicus</i> under multigenerational Cd exposure

CNO administration alleviates epileptogenesis in PTZ kindling rat model infected with hM4Di vector in DG.

Mortality(A), kindling rate(B), latency of kindling(C), severe seizure latency(D), tendency of kindling(E) and seizure stage(F) of two control groups and DREADD+CNO group. *indicates P P P P P < 0.05, DREADD+CNO group vs Non-DREADD+CNO group; CNO, clozapine N-oxide.</p

The NDR2 levels in the control, DREADD+CNO and DREADD+CNO+NDR2 groups were measured by immunofluorescence.

A and D, Representative fluorescence pictures of the CA3 and DG are displayed; B, the level of NDR2 in the DG and CA3 of the hippocampus were down-regulated in DREADD+CNO group(n = 5) compared with that of control group(n = 5, Mann-Whitney test); C, Comparing NDR2 levels in CA3 and DG in DREADD rats treated with 1 mg/kg CNO(n = 4), decreased NDR2 in CA3 was observed in DREADD rats treated with 5 and 10 mg/kg CNO(n = 4 and 5 respectively), and decreased NDR2 in DG was observed in DREADD rats treated with 10 mg/kg CNO(Kruskal-Wallis test);E, The level of NDR2 in the DG and CA3 of the hippocampus were up-regulated in DREADD+CNO+NDR2 group(n = 7) compared with that of DREADD+CNO group(Mann-Whitney test). CNO, clozapine N-oxide; DG, dentate gyrus. All data represent the median with range. *indicates P P P < 0.001. White arrows show the positive cells.</p