Search results for "Method"
showing 10 items of 13253 documents
Time evolution of non-lethal infectious diseases: a semi-continuous approach.
2005
A model describing the dynamics related to the spreading of non-lethal infectious diseases in a fixed-size population is proposed. The model consists of a non-linear delay-differential equation describing the time evolution of the increment in the number of infectious individuals and depends upon a limited number of parameters. Predictions are in good qualitative agreement with data on influenza.
A New Multinomial Accuracy Measure for Polling Bias
2014
In this article, we propose a polling accuracy measure for multi-party elections based on a generalization of Martin, Traugott, and Kennedy's two-party predictive accuracy index. Treating polls as random samples of a voting population, we first estimate an intercept only multinomial logit model to provide proportionate odds measures of each party's share of the vote, and thereby both unweighted and weighted averages of these values as a summary index for poll accuracy. We then propose measures for significance testing, and run a series of simulations to assess possible bias from the resulting folded normal distribution across different sample sizes, finding that bias is small even for polls…
A Method Based on Multi-source Feature Detection for Counting People in Crowded Areas
2019
We propose a crowd counting method for multisource feature fusion. Image features are extracted from multiple sources, and the population is estimated by image feature extraction and texture feature analysis, along with for crowd image edge detection. We count people in high-density still images. For instance, in the city’s squares, sports fields, subway stations, etc. Our approach uses a still image taken by a camera on a drone to appraise the count in the population density image, using a kind of sources of information: HOG, LBP, CANNY. We furnish separate estimates of counts and other statistical measurements through several types of sources. Support vector machine SVM, classification an…
Shared feature representations of LiDAR and optical images: Trading sparsity for semantic discrimination
2015
This paper studies the level of complementary information conveyed by extremely high resolution LiDAR and optical images. We pursue this goal following an indirect approach via unsupervised spatial-spectral feature extraction. We used a recently presented unsupervised convolutional neural network trained to enforce both population and lifetime spar-sity in the feature representation. We derived independent and joint feature representations, and analyzed the sparsity scores and the discriminative power. Interestingly, the obtained results revealed that the RGB+LiDAR representation is no longer sparse, and the derived basis functions merge color and elevation yielding a set of more expressive…
Mortalidad por defectos del tubo neural en México, 1980-1997
2003
Objetivo. Describir la mortalidad en México por defectos del tubo neural, durante el periodo 1980-1997. Material y métodos. Las tasas anuales de mortalidad estatales y nacionales, por defectos del tubo neural, se calcularon por 10 000 nacidos vivos. La tendencia temporal fue evaluada por el porcentaje de cambio anual obtenido mediante un modelo de regresión de Poisson. Se calculó la razón de mortalidad, tomando la media nacional como referencia. Las tasas y las razones se representaron gráficamente en mapas. Resultados. Durante el periodo la tasa bruta de mortalidad por defectos del tubo neural fue de 5.8 por 10 000 nacidos vivos. La anencefalia fue el tipo de defecto más frecuente (37.7%),…
Using Social Simulations in Interdisciplinary Primary Education: An Expert Appraisal
2020
Many people recognize that teaching basic skills in primary schools (reading, writing, and arithmetic) is no longer sufficient for pupils in the digital age. Therefore, governments now increasingly ask schools to add other skills (oral, digital) and to create connections between subjects (e.g., use mathematics in history lessons). In this study, we explored how social simulations can be used in primary education to meet these new goals. We conducted an expert appraisal (a qualitative Delphi method) with four experts specializing in innovating primary education. We selected three simulations that were freely available on the web, relevant for pupils’ lives and had a limited number of paramet…
Virtual Reality in Education : Focus on the Role of Emotions and Physiological Reactivity
2019
Cognitive and emotional dimensions are often linked to each other in learning experiences. Moreover, emotions and engagement can lead to better outcomes at the cognitive level. Previous research has indicated that virtual reality (VR) provides a feeling of presence and immersion, which can trigger emotionally engaging learning situations. In this study, we explore the opportunities and challenges related to the use of VR in an educational context. The focus of this article is threefold: First, we explore interdisciplinary research literature related to the use of VR for educational purposes. Second, we introduce our VR pilot study in teacher education, applying three different kinds of VR a…
Geneza Case Method i jej wpływ na kształt amerykańskiej filozofii prawa
2018
Artykuł omawia Case Method – dominującą metodę edukacyjną stosowaną w amerykańskich szkołach prawa, która polega na nauczaniu prawa poprzez analizę orzeczeń sądowych, stworzoną w latach 70. XIX w. przez Christophusa Collumbusa Langdella. Langdell postrzegał prawo jako naukę, podobną do fizyki czy chemii, a więc jako uporządkowany system obiektywnej wiedzy. Stworzona przez niego metoda nauczania służyć miała przygotowaniu osób zajmujących się prawem w sposób naukowy. W artykule przedstawiona została koncepcja prawa Langdella, oraz wpływ, jaki jego metoda nauczania wywarła na nurty amerykańskiej filozofii prawa – klasyczną jurysprudencję oraz realizm prawniczy.
Computational procedures for plastic shakedown design of structures
2004
The minimum volume design problem of elastic perfectly plastic finite element structures subjected to a combination of fixed and perfect cyclic loads is studied. The design problem is formulated in such a way that incremental collapse is certainly prevented. The search for the structural design with the required limit behaviour is effected following two different formulations, both developed on the grounds of a statical approach: the first one operates below the elastic shakedown limit and is able to provide a suboptimal design; the second one operates above the elastic shakedown limit and is able to provide the/an optimal design. The Kuhn–Tucker conditions of the two problems provide usefu…
Bounds on plastic strains for elastic plastic structures in plastic shakedown conditions
2007
The problem related to the computation of bounds on plastic deformations for structures in plastic shakedown condition (alternating plasticity) is studied. In particular, reference is made to structures discretized by finite elements constituted by elastic perfectly plastic material and subjected to a special combination of fixed and cyclic loads. The load history is known during the steady-state phase, but it is unknown during the previous transient phase; so, as a consequence, it is not possible to know the complete elastic plastic structural response. The interest is therefore focused on the computation of bounds on suitable measures of the plastic strain which characterizes just the fir…