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Objective:Utilizing multi-criterion optimization (MCO) technology to improve plan design quality based on knowledge-based planning (KBP) model.Methods:Fifty-five patients with nasopharyngeal carcinoma (NPC) who had completed radiotherapy were selected, and fixed-field intensity-modulated radiotherapy (IMRT) technology was used in each case. Among them, 40 cases were randomly selected as training set 1. Then, IMRT plans in training set 1 were preprocessed by MCO technology to construct a new training set 2. With the initial training set 1 and the processed training set 2 as training samples, the traditional KBP model and the MCO-KBP model refined by MCO technology were trained, respectively. Among the remaining 15 cases, 5 cases were randomly selected as the validation set, and the remaining 10 cases were used as the test set. After verification, the test set was used to statistically analyze the plan quality of the initial manual plan and the automatic plan generated by the traditional KBP model and the MCO-KBP model.Results:The target dose (D 95%) of plans generated by the traditional KBP model and the MCO-KBP model met the clinical requirements. Conformity index (CI) and homogeneity index (HI) were almost the same ( P>0.05), and the doses of organ at risk (OAR) of the automatic plans generated by the MCO-KBP model were lower than those of the traditional KBP model. For example, compared with the traditional KBP model, the average D max of the brainstem in the automatic plans generated by the MCO-KBP model was lower by 2.13 Gy, the average D mean of the left parotid gland was lower by 1.39 Gy, the average D mean of the right parotid gland was lower by 1.59 Gy, and the average D max of the left optic nerve was lower by 1.42 Gy, the average D max of the right optic nerve was lower by 1.16 Gy, and the average D max of the pituitary gland was lower by 1.88 Gy. All of the above-mentioned dosimetry indexes were statistically significant. Conclusion:Compared with the traditional KBP model, the IMRT plans designed by the refined MCO-KBP model have obvious advantages in the protection of OAR, which proves the feasibility of utilizing MCO technology to improve the plan design quality of the KBP model.
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Brain image segmentation algorithm based on deep learning is a research hotspot at present. In this paper, firstly, the significance of brain image segmentation and the content of related brain image segmentation algorithm are systematically described, highlighting the advantages of brain image segmentation algorithms based on deep learning. Then, this paper introduces current brain image segmentation algorithms based on deep learning from three aspects: the brain image segmentation algorithms based on problems existent to brain image, the brain image segmentation algorithms based on prior knowledge guidance and the application of general deep learning models in brain image segmentation, so as to enable researchers in relevant fields to understand current research progress more systematically. Finally, this paper provides a general direction for the further research of brain image segmentation algorithm based on deep learning.
Subject(s)
Brain , Deep Learning , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Neural Networks, ComputerABSTRACT
RESUMEN El propósito de este trabajo consistió en estudiar la relación entre la memoria de trabajo, el conocimiento previo y la generación de inferencias en la comprensión de textos. Con este propósito, 167 estudiantes universitarios completaron pruebas de memoria de trabajo y cuestionarios sobre su conocimiento acerca del cambio climático y de astronomía; luego de la lectura de dos textos expositivos referidos a ambos temas, completaron un cuestionario sobre inferencias. Los resultados del análisis de correlaciones y del análisis de senderos muestran que si bien la memoria de trabajo y el conocimiento previo específico de dominio tienen una relación con la generación de inferencias explicativas-repositivas, hay una relación de interacción de mediación entre estas variables que explica el rol de ellas sobre la generación de inferencias.
ABSTRACT The aim of this research is to study the relationship between working memory, previous knowledge, and explanation-based inferences in expository text reading. To this effect, 167 undergraduates completed three working memory tasks, and two climate change and astronomy questionnaires, after reading two expository texts on these subjects. The results of the correlations and paths analyses show that, while working memory and specific previous domain knowledge are related to the generation of explanatory and reinstatement inferences, there is a mediation interaction relationship between these variables that explains their role in the generation of inferences.
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En el presente escrito se busca establecer la base pedagógica más acorde para la generación de un modelo de educación no formal para la protección de los humedales de Bañó y los Negros, basándose en estudios previos de valoración ambiental e identificación de los factores que están incidiendo en conductas ambientalmente negativas al medio. Se define como elementos pedagógicos a considerar el aprendizaje significativo, la andragogía y el enfoque sistémico de la enseñanza. Se desarrolla una conceptualización de la educación ambiental en sus diferentes niveles: formal, no formal e informal. Se parte del aprendizaje significativo y la necesidad de relacionar nuevos conceptos con conocimientos previos, se resaltan sus principales características y se aclara lo que no se considera un aprendizaje significativo. Por otra parte, en cuanto a la educación de adultos se refiere o andragogía, se establecen algunas definiciones para la misma y sus principios fundamentales: horizontalidad y participación. Se explica cómo a través de la andragogía, el adulto aprende a valorar las experiencias propias y ajenas en función de la construcción de un proyecto de vida. Se indica además que el proceso educativo desde la andragogía debe ser personalizado e implica un auto aprendizaje donde el individuo es el único responsable del mismo. También se enfatiza cómo, desde la teoría sistémica de la enseñanza, se puede obtener una percepción de la realidad desde diferentes puntos de vista, evitando parcelaciones o sesgos ante distintos saberes o disciplinas, con el objetivo de poder establecer las diferentes interrelaciones que puedan darse para determinada(s) realidad(es). Por último, se sustenta cómo podría aplicarse tanto el aprendizaje significativo, la andragogía y la teoría sistémica de la enseñanza en la generación del modelo educativo, además de realizar las respectivas conclusiones y recomendaciones frente al tema.
The purpose of this article is to establish the most appropriate pedagogical basis for the formulation of a non-formal educational model for the protection of the Bañó and Los Negros wetlands, using previous studies on environmental assessment and identification of the factors which influence negative environmental conduct. Meaningful learning, andragogy and the systemic focus for teaching are defined as pedagogical elements. A conceptualization of environmental education in its different levels -formal, non-formal and informal- were also developed. From significant learning and the need to relate new concepts to previous knowledge the main characteristics were highlighted and it was clarified what was not considered meaningful learning. Moreover, in terms of adult education or andragogy, some definitions were established along with its fundamental principles: horizontal alignment and participation. It is explained how through andragogy adults learn to appreciate their own and others experiences around the construction of life projects. It is also indicated that the educational process from andragogy should be personalized implying self-learning in which the individual is the only one responsible for it. It also emphasizes how, through the systemic theory of teaching, it is possible to obtain a perception of reality from different points of view avoiding fragmentations or bias concerning different knowledge or disciplines in order to establish different interrelations that could occur in certain realities. Finally, how significant learning, andragogy and the systemic theory of teaching could be used in the formulation of an educational model is discussed, along with drawing the respective conclusions and recommendations concerning this matter.
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Humans , Models, Educational , Teaching , Community Participation , KnowledgeABSTRACT
El objetivo de este trabajo es estudiar la relación entre la atención sostenida y el conocimiento previo con la comprensión de narraciones en niños de 4 años de edad. La muestra comprendía 30 niños a los que se les presentaron dos cuentos y se les solicitó que respondieran una serie de preguntas para evaluar comprensión de información literal y la generación de inferencias. Se utilizaron además una prueba de atención sostenida y un cuestionario de conocimiento previo. Los resultados demuestran la existencia de una asociación entre la comprensión de textos y el conocimiento previo, y se observa una relación diferenciada del conocimiento previo con distintos aspectos de la comprensión, comprobándose una asociación con la habilidad para generar inferencias, no así con la comprensión de información de tipo literal. Además, la atención sostenida posee valor predictivo sobre la comprensión de texto global, específicamente sobre la comprensión de información de tipo literal.
The aim of this project is to study the relationship between sustained attention and prior knowledge with narrative comprehension in 4 years-old children. For that purpose, two narrative stories and a questionnaire to assess comprehension of literal information and inference generation were administrated to 30 children. Also, a sustained attention test and a prior knowledge questionnaire were administrated. Results showed an association between text comprehension with prior knowledge, and an association of sustained attention with different aspects of text comprehension, observing an association with the ability to generate inferences, but not with literal information comprehension. Also, a predictive role of sustained attention on global comprehension and more specifically on literal information comprehension was found.
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Child, Preschool , Child , Narration , Comprehension , AttentionABSTRACT
This study aims to compare the learning process and achievement of the third year students who have undergone the old style curriculum and the fourth year students had undergone the Student Centered Learning approach for the past year. These two different groups were mixed for tutorial discussions. The tutorial sessions were provided with one scenario - the subject of Oral Medicine III: the compromisedpatient. We focused on comparing the results of both groups on the process of learning and the block test. The eight mixed tutorial groups comprised of 16-20 students (half from the old style curriculum and half from the student-centered approach group) each. They were assessed by two tutors on the learning process: the time schedule, activity during discussion and relevance of questions asked. Furthermore, the study compared the results of the block test on 5 multiple choice questions (MCQs) on the compromisedpatient among 100 MCQs at the final examination. There was no significant difference between the two groups for the process of learning and the result of the block test. This study challenges the belief that new concepts or knowledge require prior knowledge; is known as learning across boundaries.
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Dados históricos de precipitação máxima são utilizados para realizar previsões de chuvas extremas, cujo conhecimento é de grande importância na elaboração de projetos agrícolas e de engenharia hidráulica. A distribuição generalizada de valores extremos (GEV) tem sido aplicada com freqüência nesses tipos de estudos, porém, algumas dificuldades na obtenção de estimativas confiáveis sobre alguma medida dos dados têm ocorrido devido ao fato de que, na maioria das situações, tem-se uma quantidade escassa de dados. Uma alternativa para obter melhorias na qualidade das estimativas seria utilizar informações dos especialistas de determinada área em estudo. Sendo assim, objetiva-se neste trabalho analisar a aplicação da Inferência Bayesiana com uma distribuição a priori baseada em quantis extremos, que facilite a incorporação dos conhecimentos fornecidos por especialistas, para obter as estimativas de precipitação máxima para os tempos de retorno de 10 e 20 anos e seus respectivos limites superiores de 95 por cento, para o período anual e para os meses da estação chuvosa em Jaboticabal (SP). A técnica Monte Carlo, via Cadeias de Markov (MCMC), foi empregada para inferência a posteriori de cada parâmetro. A metodologia Bayesiana apresentou resultados mais acurados e precisos, tanto na estimação dos parâmetros da distribuição GEV, como na obtenção dos valores de precipitação máxima provável para a região de Jaboticabal, apresentando-se como uma boa alternativa na incorporação de conhecimentos a priori no estudo de dados extremos.
Historical maximum rainfall data are used to forecast extreme rainfall, which is important to elaborate agricultural and hydraulic engineering projects. Generalized Extreme Value Distribution (GEV) has been applied in such type of studies. Since those values are extracted from the upper (or lower) tail of the original distribution, a scarce amount of data is obtained in most cases, which may be a problem acquiring reliable estimates about some measure of interest. An alternative to overcome this potential problem would be the use of information available from experts in the area. Therefore, this paper intended to analyze the application of the Bayesian Inference using a priori distribution based on extreme quantiles, which facilitates the incorporation of the information supplied by the experts in order to determine the punctual and the 95 percent upper limit estimates of the probable maximum precipitation for return periods of 10 and 20 years, yearly and monthly in Jaboticabal, São Paulo State, Brazil. Markov Chain Monte Carlo (MCMC) methods were used to a posterior inference of each parameter. Bayesian inference yielded more suitable and accurate results in the estimation of the parameters of the GEV distribution as well as in the determination of the values of the probable maximum precipitation estimates for Jaboticabal. It turned out as an interesting way of incorporating prior knowledge to the study of extreme data.
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During surgery and radiation therapy,demands for higher quality of quantification and visualization of cerebral vessels need to be met.Hence,automatic (or semi-automatic) extractions of accurate cerebral vessel information seem particularly important.This paper reviews the cerebral vessel segmentation methods used in recent years,including statistics-based segmentation,deformable model,multi-scale method,prior knowledgebased method,and so on.The methods are divided into the following three categories:voxel intensity based approach,vascular tubular structure based approach,and prior knowledge-based approach.
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Se evaluaron los efectos de distintos tipos funcionales de contactos previos con los referentes de un texto (historia de referencialidad e historia situacional efectiva) sobre la ejecución de estudiantes universitarios en una prueba de ajuste lector. Participaron cinco grupos experimentales diferenciados por el tipo de historia de contacto construida mediante un entrenamiento. Cada tipo de historia era progresivamente más complejo: Contextual, Suplementario, Selector, Sustitutivo Referencial y Sustitutivo No Referencial Un sexto grupo (control) no tuvo ningún entrenamiento. Los seis grupos fueron posteriormente expuestos a la prueba de ajuste lector, consistente en preguntas de diferente complejidad funcional. Los resultados revelan una función positiva entre la complejidad de la historia de contacto y el porcentaje total de aciertos en la prueba de ajuste lector (excepto en el grupo con la historia más compleja). Se discuten los resultados enfatizando las funciones disposicionales de los diferentes tipos de historia en el ajuste lector, contrastándolas con la noción tradicional de conocimiento previo.
This study evaluated the effects of different types of previous contacts with the referents of a text (referential history and effective situational history) on the performance of University students on a reading adjustment test. Five experimental groups differentiated from each other by the type of history elaborated on a training session participated in the study. The types of histories were progressively more complex: Contextual, Supplementary, Selective, Referential Substitutive and Non-Referential Substitutive. For subjects in the control group no history was constructed and they were directly administered the reading adjustment test. Results suggest that there is a direct function between the complexity of the contact history and the percentage of total correct responses in the reading adjustment test (except in the group with the most complex history). Results are analysed emphasizing the dispositional functions of different types of history in reading adjustment, as compared with the traditional notion of prior knowledge.
Foram avaliados os efeitos de vários tipos funcionais de contatos prévios mediante os referentes de um texto (historia de referência e historia situacional efetiva) sobre o desempenho de estudantes universitários em uma prova de ajuste leitor. Participaram cinco grupos experimentais diferençados pela classe de história de contato construída depois de um treinamento. Cada classe de história era progressivamente mais complexa: contextual, suplementaria, seletora, substitutiva referencial e substitutiva não referencial. Um sexto grupo não teve treinamento. Posteriormente, aos seis grupos lhes foi aplicada uma prova de ajuste leitor, consistente em perguntas de diferente complexidade funcional. Os resultados indicam uma função positiva entre a complexidade da história de contato e a porcentagem total de acertos na prova de ajuste leitor (salvo no grupo que tenha a história mais complexa). São analisados os resultados enfatizando nas funções disposicionais das diversas classes de história no ajuste leitor, contrastando-as com a noção tradicional de conhecimento prévio.