GDINA: An R Package for Cognitive Diagnosis Modeling

Cognitive diagnosis models (CDMs) have attracted increasing attention in educational measurement because of their potential to provide diagnostic feedback about students' strengths and weaknesses. This article introduces the feature-rich R package GDINA for conducting a variety of CDM analyses. Built upon a general model framework, a number of CDMs can be calibrated using the GDINA package. Functions are also available for evaluating model-data fit, detecting differential item functioning, validating the item and attribute association, and examining classification accuracy. A grapical user interface is also provided for researchers who are less familar with R. This paper contains both technical details about model estimation and illustrations about how to use the package for data analysis. The GDINA package is also used to replicate published results, showing that it could provide comparable model parameter estimation

BASIC:A Comprehensive Model for so _xFormation Mechanism and Optimization in Municipal Solid Waste (MSW) Combustion

[Image: see text] Municipal solid waste (MSW) incineration is one of the main techniques currently used for waste to energy (WTE) conversion in China. Although the sulfur content in MSW is lower than that in coal, its emission cannot be neglected due to environmental pollution, malodor, health problems, and global climate change. Therefore, it is particularly important to effectively predict and control the sulfur pollutants. In this study, a comprehensive model was developed and coupled with the full combustion process bed model bulk accumulated solids incineration code (BASIC) to investigate the formation and transformation processes of sulfur in MSW incineration. The submodels of the four stages in the MSW combustion processes; governing equations of mass, momentum, and energy conservation; and various chemical reactions were included in the model. Based on this model, the effects of different parameters on the formation of sulfur pollutants during the incineration process were studied under different operating conditions. The study finds that for SO(X) formation, initial temperature, primary air volume, and material particle size have significant impacts, whereas pressure shows a less significant effect. This article also considers H(2)S, COS, and CS(2) formation under different conditions. An optimization study was performed to reduce SO(X) pollutants

Integrating Differential Evolution Optimization to Cognitive Diagnostic Model Estimation

A log-linear cognitive diagnostic model (LCDM) is estimated via a global optimization approach- differential evolution optimization (DEoptim), which can be used when the traditional expectation maximization (EM) fails. The application of the DEoptim to LCDM estimation is introduced, explicated, and evaluated via a Monte Carlo simulation study in this article. The aim of this study is to fill the gap between the field of psychometric modeling and modern machine learning estimation techniques and provide an alternative solution in the model estimation

EpCAM Is an Endoderm-Specific Wnt Derepressor that Licenses Hepatic Development

SummaryMechanisms underlying cell-type-specific response to morphogens or signaling molecules during embryonic development are poorly understood. To learn how response to the liver-inductive Wnt2bb signal is achieved, we identify an endoderm-enriched, single transmembrane protein, epithelial-cell-adhesion-molecule (EpCAM), as an endoderm-specific Wnt derepressor in zebrafish. hi2151/epcam mutants exhibit defective liver development similar to prt/wnt2bb mutants. EpCAM directly binds to Kremen1 and disrupts the Kremen1-Dickkopf2 (Dkk2) interaction, which prevents Kremen1-Dkk2-mediated removal of Lipoprotein-receptor-related protein 6 (Lrp6) from the cell surface. These data lead to a model in which EpCAM derepresses Lrp6 and cooperates with Wnt ligand to activate Wnt signaling through stabilizing membrane Lrp6 and allowing Lrp6 clustering into active signalosomes. Thus, EpCAM cell autonomously licenses and cooperatively activates Wnt2bb signaling in endodermal cells. Our results identify EpCAM as the key molecule and its functional mechanism to confer endodermal cells the competence to respond to the liver-inductive Wnt2bb signal