Research on operation scenario based aircraft power system architecture analysis and modelling

Aircraft power system is a complex system consisting of the power generation system, the power management and distribution system, and the power consumption system, which accounts for the aircraft's major fuel consumption and emissions. This paper proposes a scenario-based comprehensive power requirement analysis and system architecture methodology in order to alleviate the risk of systems over-design and discoordination caused by traditional bottom-up load collection and individual system design. Starting from the operation scenario, system functions are identified and corresponding physical architecture and power loads are analysed. Given the complexity of operation scenarios and aircraft power system, model-based system engineering methodology is applied to the top-down aircraft power system architecture design. SysML tool is used to carry out to analyse the aircraft power system architecture during taxi scenario, which provides great advantages on model tracing and reuse.

Intelligent Feedback on Hypothesis Testing

Hypothesis testing involves a complex stepwise procedure that is challenging for many students in introductory university statistics courses. In this paper we assess how feedback from an Intelligent Tutoring System can address the logic of hypothesis testing and whether such feedback contributes to first-year social sciences students’ proficiency in carrying out hypothesis tests. Feedback design combined elements of the model-tracing and constraint-based modeling paradigms, to address both the individual steps as well as the relations between steps. To evaluate the feedback, students in an experimental group (N = 163) received the designed intelligent feedback in six hypothesis-testing construction tasks, while students in a control group (N = 151) only received stepwise verification feedback in these tasks. Results showed that students receiving intelligent feedback spent more time on the tasks, solved more tasks and made fewer errors than students receiving only verification feedback. These positive results did not transfer to follow-up tasks, which might be a consequence of the isolated nature of these tasks. We conclude that the designed feedback may support students in learning to solve hypothesis-testing construction tasks independently and that it facilitates the creation of more hypothesis-testing construction tasks.

EvoLogic: Sistema Tutor Inteligente para Ensino de Lógica

Este artigo apresenta o modelo cognitivo do Sistema Tutor Inteligente EvoLogic, desenvolvido para auxiliar no processo de ensino-aprendizagem da Dedução Natural na Lógica Proposicional. O EvoLogic consiste em 3 agentes, entre os quais o agente Pedagógico (tratado aqui como o modelo do aluno) e o agente Especialista (baseado em um algoritmo genético) compõem o modelo cognitivo. O objetivo do artigo, além de apresentar o EvoLogic, é analisar a eficiência do STI em um exercício conhecido que já foi estudado na literatura (aplicado a 57 alunos). Os resultados mostram que o EvoLogic obteve todas as soluções apresentadas pelos alunos, permitindo seguir os passos individuais de cada aluno, fornecendo feedback em tempo real, com base nos passos que os alunos estão seguindo, conhecido como model tracing.

The ALMA-PILS survey: the first detection of doubly deuterated methyl formate (CHD2OCHO) in the ISM

Studies of deuterated isotopologues of complex organic molecules can provide important constraints on their origin in star formation regions. In particular, the abundances of deuterated species are very sensitive to the physical conditions in the environment where they form. Because the temperatures in star formation regions are low, these isotopologues are enhanced to significant levels, which enables the detection of multiply deuterated species. However, for complex organic species, so far only the multiply deuterated variants of methanol and methyl cyanide have been reported. The aim of this paper is to initiate the characterisation of multiply deuterated variants of complex organic species with the first detection of doubly deuterated methyl formate, CHD2OCHO. We use ALMA observations from the Protostellar Interferometric Line Survey (PILS) of the protostellar binary IRAS 16293–2422 in the spectral range of 329.1 GHz to 362.9 GHz. Spectra towards each of the two protostars are extracted and analysed using a local thermal equilibrium model in order to derive the abundances of methyl formate and its deuterated variants. We report the first detection of doubly deuterated methyl formate CHD2OCHO in the ISM. The D-to-H ratio (D/H ratio) of CHD2OCHO is found to be 2–3 times higher than the D/H ratio of CH2DOCHO for both sources, similar to the results for formaldehyde from the same dataset. The observations are compared to a gas-grain chemical network coupled to a dynamical physical model, tracing the evolution of a molecular cloud until the end of the Class 0 protostellar stage. The overall D/H ratio enhancements found in the observations are of about the same magnitude as the predictions from the model for the early stages of Class 0 protostars. However, that the D/H ratio of CHD2OCHO is higher than that of CH2DOCHO is still not predicted by the model. This suggests that a mechanism enhances the D/H ratio of singly and doubly deuterated methyl formate that is not in the model, for instance, mechanisms for H–D substitutions. This new detection provides an important constraint on the formation routes of methyl formate and outlines a path forward in terms of using these ratios to determine the formation of organic molecules through observations of differently deuterated isotopologues towards embedded protostars.

ANALYTICAL MODEL TRACING DEFORMATIONS IN MULTISTOREY LARGE TIMBER PANEL BUILDING

This paper deals with the deformation characteristics of wood-framed residential, small commercial and hotel buildings with sheathing. Recent building structures are based on large panel or modular technology, where elements in the form of diaphragms or modules are constructed in an industrial plant and then transported to the site for assembly. The document presents diagrams of building assembly and technologies for realization. The significant influence of excessive vertical deformations in multistorey wood-framed buildings on their performance and serviceability is underlined. These deformations are caused by different factors which are identified and analytically described. The paper outlines the analytically complex model for the evaluation and control of deformations in the design, construction and exploitation of multistorey wood-framed buildings. An example of the application of the proposed analytical model at the design stage concludes the paper.

Information Technologies for Learning Principles of Fault-Tolerant Systems

In this chapter, the authors present a methodology for developing a model-tracing cognitive tutor. The methodology is based on Bayesian probabilistic networks for generating pedagogical interventions. The presented probabilistic model increases fidelity assessment due to its ability of independently diagnosing the degree of mastery for every knowledge component involved in students' actions; fidelity assessment in education is the ability to represent students' cognitive states as close as possible for analysis and evaluation. The cognitive tutor was developed to promote a self-regulated learning approach with an open learner model. The open learner model let students change the learning flow by changing the assigned tasks. The authors explain in detail the structural construction and employed algorithms for developing a model-tracing cognitive tutor in the domain of fault-tolerant systems. Preliminary results and future work are also discussed to assess effectiveness of the proposed approach and its implication in actual educational programs.

The selective grinding prosthetic feeding aid frequency influence towards premaxilla position on infant with complete unilateral cleft lip and palate

Objective: The purpose of the research was to analyze the influence of selective grinding frequency towards premaxilla position of infant with complete unilateral cleft lip and palate using prosthetic feeding aid.Material and Methods: Ten infants with complete unilateral cleft lip and palate with wide alveolar cleft and rotating position of premaxilla were treated with prosthetic feeding aid. Impression was done twice to each subject before and after prosthetic feeding aid placement. The photograph was taken from each working model. Tracing was made on each photograph using photoQuad program on the assigned postulate spots. Adjustment towards the prosthetic feeding aid device was done every two week with selective grinding on the anatomical surface of acrylic on the palatolateral major and anteromedial minor defects, and relining with soft liner on the labial of anatomical surface was also done. Anatomical surface selective grinding was not exceeded 1–1.5 mm on every visit. The correlation analyze between selective grinding frequency of prosthetic feeding aid and premaxilla position used the Pearson correlation coefficient.Results: The correlation analysis between selective grinding prosthetic feeding aid frequency with premaxilla position on infant with complete unilateral cleft lip and palate have positive correlation with value of 23% or r = 0.479 and t-count = 1.544 or p-value = 0.1611.Conclusion: The more frequent the selective grinding on prosthetic feeding aid, the higher the premaxilla position change will increase towards midsagittal.

Rule-based Cognitive Modeling and Model Tracing in a Math Story Problem Tutor

Intelligent Tutoring Systems (ITSs) are intended to help in tutoring the students in specific domains typically by improving their problem solving skills. An important aspect of such ITSs is their ability to solve the generated problems in the same way that the student would in addition to interpreting the student actions to provide relevant feedback and help. Cognitive models that mimic the way knowledge is represented in human minds are excellent means toward achieving this goal. This paper discusses cognitive modelling in the MAth Story problem Tutor (MAST). MAST is a Web-based ITS that can generate probability story problems of different contexts, types and difficulty levels. The paper also discusses the model tracing approach of MAST to interpret the student actions in symbolizing the word problems and estimating the required probabilities to provide relevant feedback and help. A major contribution of the paper is in considering the symbolization of the probability word problems to convert them to the symbolic form and tracing the students errors in this process. As an example, the paper considers the context of rolling a die and tossing a coin. Evaluation results have shown the ability of MAST to considerably improve the probability story problem solving skills of the students.