An Evolutionary Neural Network Approach for Slopes Stability Assessment

A current big challenge for developed or developing countries is how to keep large-scale transportation infrastructure networks operational under all conditions. Network extensions and budgetary constraints for maintenance purposes are among the main factors that make transportation network management a non-trivial task. On the other hand, the high number of parameters affecting the stability condition of engineered slopes makes their assessment even more complex and difficult to accomplish. Aiming to help achieve the more efficient management of such an important element of modern society, a first attempt at the development of a classification system for rock and soil cuttings, as well as embankments based on visual features, was made in this paper using soft computing algorithms. The achieved results, although interesting, nevertheless have some important limitations to their successful use as auxiliary tools for transportation network management tasks. Accordingly, we carried out new experiments through the combination of modern optimization and soft computing algorithms. Thus, one of the main challenges to overcome is related to the selection of the best set of input features for a feedforward neural network for earthwork hazard category (EHC) identification. We applied a genetic algorithm (GA) for this purpose. Another challenging task is related to the asymmetric distribution of the data (since typically good conditions are much more common than bad ones). To address this question, three training sampling approaches were explored: no resampling, the synthetic minority oversampling technique (SMOTE), and oversampling. Some relevant observations were taken from the optimization process, namely, the identification of which variables are more frequently selected for EHC identification. After finding the most efficient models, a detailed sensitivity analysis was applied over the selected models, allowing us to measure the relative importance of each attribute in EHC identification

SPATIAL TRANSFORMATION PATTERN DUE TO COMMERCIAL ACTIVITY IN KAMPONG HOUSE

ABSTRACT Kampung houses are houses in kampung area of the city. Kampung House oftenly transformed into others use as urban dynamics. One of the transfomation is related to the commercial activities addition by the house owner. It make house with full private space become into mixused house with more public spaces or completely changed into full public commercial building. This study investigate the spatial transformation pattern of the kampung houses due to their commercial activities addition. Site observations, interviews and questionnaires were performed to study the spatial transformation. This study found that in kampung houses, the spatial transformation pattern was depend on type of commercial activities and owner perceptions, and there are several steps of the spatial transformation related the commercial activity addition. Keywords: spatial transformation pattern; commercial activity; owner perception, kampung house; adaptabilit

Solución rápida y automática de parámetros hipocentrales para eventos sísmicos, mediante el empleo de técnicas de aprendizaje de máquina

La generación de alertas tempranas para sismos es de gran utilidad, en particular para la ciudad de Bogotá-Colombia, dada su importancia social y económica para el país. Con base en la información de la estación sismológica de El Rosal, la cual es una estación de banda ancha y tres componentes, localizada muy cerca de la ciudad, perteneciente al Servicio Geológico Colombiano (SGC) se desarrolló un modelo de regresión basado en máquinas de vectores de soporte (SVM), con un kernel polinomial normalizado, usando como datos de entrada algunas características de la porción inicial de la onda P empleadas en trabajos anteriores tales como la amplitud máxima, los coeficientes de regresión lineal de los mismos, los parámetros de ajuste logarítmico de la envolvente y los valores propios de la relación de las tres componentes del sismograma. El modelo fue entrenado y evaluado aplicando correlación cruzada, permitiendo llevar a cabo el cálculo de la magnitud y la localización de un evento sísmico con una longitud de señal de tan solo cinco segundos. Con el modelo propuesto se logró la determinación de la magnitud local con una precisión de 0.19 unidades de magnitud, la distancia epicentral con una precisión de alrededor de 11 kilómetros, la profundidad hipocentral con una precisión de aproximadamente 40 kilómetros y el azimut de llegada con una precisión de 45°. Las precisiones obtenidas en magnitud y distancia epicentral son mejores que las encontradas en trabajos anteriores, donde se emplean gran número de eventos para la determinación del modelo y en los demás parámetros hipocentrales son del mismo orden. Este trabajo de investigación realiza un aporte considerable en la generación de alertas tempranas para sismos, no solamente para el país sino para cualquier otro lugar donde se deseen implementar los modelos aquí propuestos y es un excelente punto de partida para investigaciones futuras.Abstract. Earthquake early warning alerts generation is very useful, especially for the city of Bogotá-Colombia, given the social and economic importance of this city for the country. Based on the information from the seismological station “El Rosal”, which is a broadband and three components station, located very near the city that belongs to the Servicio Geológico Colombiano (SGC) a Support Vector Machine Regression (SVMR) model was developed, using a Normalized Polynomial Kernel, using as input some characteristics of the initial portion of the P wave used in earlier works such as the maximum amplitude, the linear regression coefficients of such amplitudes, the logarithmic adjustment parameters of the envelope of the waveform and the eigenvalues of the relationship between the three seismogram components of each band. The model was trained and evaluated by applying a cross-correlation strategy, allowing to calculate the magnitude and location of a seismic event with only five seconds of signal. With the proposed model it was possible to estimate local magnitude with an accuracy of 0.19 units of magnitude, epicentral distance with an accuracy of about 11 km, the hipocentral depth with a precision of approximately 40 km and the arrival back-azimut with a precision of 45°. Accuracies obtained in magnitude and epicentral distance are better that those found in earlier works, where a large number of events were used for model determination, and the other hipocentral parameters precisions obtained here are of the same order. This research work makes a considerable contribution in the generation of seismic early warning alerts, not only for the country but for any other place where proposed models here can be applied and is a very good starting point for future research.Doctorad

Minimising mathematical anxiety in teaching mathematics and assessing student’s work

This paper builds up a theoretical perspective and supports a possibility of creating a special assessment environment for students, where mathematical knowledge and understanding can be assessed with a reduced number of external psychological factors that may affect such assessment. A concept of a zone with minimal effect of anxiety is introduced and described. Students’ successful work on extending the zone by means of a carefully selected chain of questions, where some questions only are part of a real assessment, allows students to reconsider their attitudes towards mathematics and assist teachers to identify some students’ main learning difficulties as of psychological character. Further suggestions about developing and investigating special assessment environments are outlined and discussed

Bowdoin Orient v.116, no.1-27 (1986-1987)

https://digitalcommons.bowdoin.edu/bowdoinorient-1980s/1007/thumbnail.jp

The SDSU Collegian September 1970- May 2000 Index

The purpose of this index is to provide a subject guide to the SDSU Collegian. Included are all articles written by the staff as well as wire-service news stories. Excluded are brief announcements, notices, and minor sport events. This issue cumulates two publishing years, September 1970- May 2000