21 research outputs found
A review of population-based metaheuristics for large-scale black-box global optimization: Part A
Scalability of optimization algorithms is a major challenge in coping with the ever growing size of optimization problems in a wide range of application areas from high-dimensional machine learning to complex large-scale engineering problems. The field of large-scale global optimization is concerned with improving the scalability of global optimization algorithms, particularly population-based metaheuristics. Such metaheuristics have been successfully applied to continuous, discrete, or combinatorial problems ranging from several thousand dimensions to billions of decision variables. In this two-part survey, we review recent studies in the field of large-scale black-box global optimization to help researchers and practitioners gain a bird’s-eye view of the field, learn about its major trends, and the state-of-the-art algorithms. Part of the series covers two major algorithmic approaches to large-scale global optimization: problem decomposition and memetic algorithms. Part of the series covers a range of other algorithmic approaches to large-scale global optimization, describes a wide range of problem areas, and finally touches upon the pitfalls and challenges of current research and identifies several potential areas for future research
Pedestrian Detection Algorithms using Shearlets
In this thesis, we investigate the applicability of the shearlet transform for the task of pedestrian detection. Due to the usage of in several emerging technologies, such as automated or autonomous vehicles, pedestrian detection has evolved into a key topic of research in the last decade. In this time period, a wealth of different algorithms has been developed. According to the current results on the Caltech Pedestrian Detection Benchmark the algorithms can be divided into two categories. First, application of hand-crafted image features and of a classifier trained on these features. Second, methods using Convolutional Neural Networks in which features are learned during the training phase. It is studied how both of these types of procedures can be further improved by the incorporation of shearlets, a framework for image analysis which has a comprehensive theoretical basis
Deep learning-based diagnostic system for malignant liver detection
Cancer is the second most common cause of death of human beings, whereas liver cancer is the fifth most
common cause of mortality. The prevention of deadly diseases in living beings requires timely, independent,
accurate, and robust detection of ailment by a computer-aided diagnostic (CAD) system. Executing such intelligent CAD requires some preliminary steps, including preprocessing, attribute analysis, and identification.
In recent studies, conventional techniques have been used to develop computer-aided diagnosis algorithms.
However, such traditional methods could immensely affect the structural properties of processed images with
inconsistent performance due to variable shape and size of region-of-interest. Moreover, the unavailability of sufficient datasets makes the performance of the proposed methods doubtful for commercial use.
To address these limitations, I propose novel methodologies in this dissertation. First, I modified a
generative adversarial network to perform deblurring and contrast adjustment on computed tomography
(CT) scans. Second, I designed a deep neural network with a novel loss function for fully automatic precise
segmentation of liver and lesions from CT scans. Third, I developed a multi-modal deep neural network
to integrate pathological data with imaging data to perform computer-aided diagnosis for malignant liver
detection.
The dissertation starts with background information that discusses the proposed study objectives and the workflow. Afterward, Chapter 2 reviews a general schematic for developing a computer-aided algorithm, including image acquisition techniques, preprocessing steps, feature extraction approaches, and machine learning-based prediction methods.
The first study proposed in Chapter 3 discusses blurred images and their possible effects on classification.
A novel multi-scale GAN network with residual image learning is proposed to deblur images. The second
method in Chapter 4 addresses the issue of low-contrast CT scan images. A multi-level GAN is utilized
to enhance images with well-contrast regions. Thus, the enhanced images improve the cancer diagnosis
performance. Chapter 5 proposes a deep neural network for the segmentation of liver and lesions from
abdominal CT scan images. A modified Unet with a novel loss function can precisely segment minute lesions.
Similarly, Chapter 6 introduces a multi-modal approach for liver cancer variants diagnosis. The pathological data are integrated with CT scan images to diagnose liver cancer variants.
In summary, this dissertation presents novel algorithms for preprocessing and disease detection. Furthermore,
the comparative analysis validates the effectiveness of proposed methods in computer-aided diagnosis
Anales del XIII Congreso Argentino de Ciencias de la Computación (CACIC)
Contenido:
Arquitecturas de computadoras
Sistemas embebidos
Arquitecturas orientadas a servicios (SOA)
Redes de comunicaciones
Redes heterogéneas
Redes de Avanzada
Redes inalámbricas
Redes móviles
Redes activas
Administración y monitoreo de redes y servicios
Calidad de Servicio (QoS, SLAs)
Seguridad informática y autenticación, privacidad
Infraestructura para firma digital y certificados digitales
Análisis y detección de vulnerabilidades
Sistemas operativos
Sistemas P2P
Middleware
Infraestructura para grid
Servicios de integración (Web Services o .Net)Red de Universidades con Carreras en Informática (RedUNCI
O uso de múltiplos enxames na otimização de problemas com vários objetivos
Resumo: A computação bioinspirada permite a resolução de uma gama de problemas computacionais. Dentre as várias meta-heurísticas existentes, o algoritmo PSO (Particle Swarm Optimization) tem sido aplicado eficientemente para resolver problemas de otimização. Inicialmente empregado na resolução de problemas com um objetivo, a técnica tem sido investigada para solucionar problemas multiobjetivo. O principal objetivo desta tese de doutorado é a proposta de estratégias distribuídas para a execução do algoritmo PSO em diversas topologias conectando múltiplos enxames para resolver problemas com vários objetivos. A adoção de múltiplos enxames parte da constatação de que a otimização pode consumir onerosos recursos computacionais. Assim, investigar e propor novos métodos para a execução do algoritmo de forma paralela e distribuída torna-se uma iniciativa relevante. Neste trabalho, os indivíduos do algoritmo PSO são divididos em subpopulações independentes entre si e que ocasionalmente compartilham indivíduos. Diversas topologias e estratégias de comunicação para conectar os enxames foram investigadas, que determinam quais subpopulações trocam informações entre si. A influência exercida pela topologia na otimização de problemas com um objetivo é avaliada. Esta investigação inicial serviu para verificar se o uso de múltiplos enxames é relevante. Considerando os resultados obtidos, pôde-se constatar que esse modelo exerce um efeito positivo no processo de otimização. Foi possível indicar quais topologias apresentam melhor desempenho e qual a configuração, em termos de número de subpopulações, é mais eficiente. Tais constatações foram motivações para conceber estratégias distribuídas para resolver problemas com vários objetivos, incluindo uma estratégia baseada na decomposição de funções. Estudos empíricos são conduzidos para avaliar o impacto da otimização cooperativa, incluindo fatores relacionados à comunicação exigida entre as subpopulações. A partir desses resultados foi possível determinar qual estratégia baseada no algoritmo PSO é mais indicada, considerando as características de diferentes problemas de otimização
Anales del XIII Congreso Argentino de Ciencias de la Computación (CACIC)
Contenido:
Arquitecturas de computadoras
Sistemas embebidos
Arquitecturas orientadas a servicios (SOA)
Redes de comunicaciones
Redes heterogéneas
Redes de Avanzada
Redes inalámbricas
Redes móviles
Redes activas
Administración y monitoreo de redes y servicios
Calidad de Servicio (QoS, SLAs)
Seguridad informática y autenticación, privacidad
Infraestructura para firma digital y certificados digitales
Análisis y detección de vulnerabilidades
Sistemas operativos
Sistemas P2P
Middleware
Infraestructura para grid
Servicios de integración (Web Services o .Net)Red de Universidades con Carreras en Informática (RedUNCI