998 resultados para Broken line
Resumo:
In this paper we present an improved scheme for line and edge detection in cortical area V1, based on responses of simple and complex cells, truly multi-scale with no free parameters. We illustrate the multi-scale representation for visual reconstruction, and show how object segregation can be achieved with coarse-to-finescale groupings. A two-level object categorization scenario is tested in which pre-categorization is based on coarse scales only, and final categorization on coarse plus fine scales. Processing schemes are discussed in the framework of a complete cortical architecture.
Resumo:
Empirical studies concerning face recognition suggest that faces may be stored in memory by a few canonical representations. Models of visual perception are based on image representations in cortical area V1 and beyond, which contain many cell layers for feature extraction. Simple, complex and end-stopped cells provide input for line, edge and keypoint detection. Detected events provide a rich, multi-scale object representation, and this representation can be stored in memory in order to identify objects. In this paper, the above context is applied to face recognition. The multi-scale line/edge representation is explored in conjunction with keypoint-based saliency maps for Focus-of-Attention. Recognition rates of up to 96% were achieved by combining frontal and 3/4 views, and recognition was quite robust against partial occlusions.
Resumo:
Disparity energy models (DEMs) estimate local depth information on the basis ofVl complex cells. Our recent DEM (Martins et al, 2011 ISSPlT261-266) employs a population code. Once the population's cells have been trained with randorn-dot stereograms, it is applied at all retinotopic positions in the visual field. Despite producing good results in textured regions, the model needs to be made more precise, especially at depth transitions.
Resumo:
A feature detection system has been developed for real-time identification of lines, circles and people legs from laser range data. A new method sutable for arc/circle detection is proposed: the Inscribed Angle Variance (IAV). Lines are detected using a recursive line fitting method.
Resumo:
The problem with the adequacy of radial basis function neural networks to model the inside air temperature as a function of the outside air temperature and solar radiation, and the inside relative humidity in an hydroponic greenhouse is addressed.
Resumo:
The Proportional Integral and Devirative (PID) controller autotuning is an important problem, both in practical and theoretical terms. The autotuning procedure must take place in real-time, and therefore the corresponding optimisation procedure must also be executed in real-time and without disturbing on-line control.
Resumo:
Isolationism and neutrality are two of the recurrent themes in the study of the history of the U.S. foreign policy in the interwar years. The trauma of the Great War, which had swept away 130.000 U.S. lives and had cost $30 billion, had led public opinion to strongly oppose any involvement with European affairs. Besides, the urgent need for economic recovery during the dismal years of the Great Depression did not leave Roosevelt much room for manoeuvre to influence international events. His positions regarding the intentions of the Fascist states remained, at best, ambivalent. These facts notwithstanding, about 2800 U.S. citizens crossed the Atlantic and rushed in to help democratic Spain, which was on the verge of becoming one more hostage in the hands of the Fascism. They joined the other British, Irish and Canadian volunteers and formed the XV International Brigade. 900 Americans never returned home. This alone should challenge the commonly held assumption that the American people were indifferent to the rise of the Fascist threat in Europe. But it also begs other questions. Considering the prevailing isolationist mood, what really motivated them? With what discursive elements did these men construct their anti Fascist representations? How far did their understanding of the Spanish democracy correspond to their own American democratic ideal? In what way did their war experience across the Atlantic mould their perception of U.S. politics (both domestic and foreign)? How far did the Spanish Civil War constitute one first step towards the realization that the U.S. might actually be drawn into another international conflict of unpredictable consequences? Last but not the least, what ideological, political and cultural complicity existed between the men from the English-speaking battalions? In order to unearth some of the answers, I intend to examine their letters and see how these men recorded the historical events in which they took part. Their correspondence emerged from the desire to prove their commitment to a common cause and spoke of a common war experience, but each letter, in its uniqueness, ends up mirroring not only the social and political background of each individual fighter, but also his own particular perspective of the war, of world politics and of the Spanish people. We shall see how these letters differ and converge and how these particular accounts weave, as in an epistolary novel, a larger-than-life narrative of outrage and solidarity, despair and hope.
Resumo:
This study describes the on-line operation of a seismic detection system to act at the level of a seismic station providing similar role to that of a STA /LTA ratio-based detection algorithms. The intelligent detector is a Support Vector Machine (SVM), trained with data consisting of 2903 patterns extracted from records of the PVAQ station, one of the seismographic network's stations of the Institute of Meteorology of Portugal (IM). Records' spectral variations in time and characteristics were reflected in the SVM input patterns, as a set of values of power spectral density at selected frequencies. To ensure that all patterns of the sample data were within the range of variation of the training set, we used an algorithm to separate the universe of data by hyper-convex polyhedrons, determining in this manner a set of patterns that have a mandatory part of the training set. Additionally, an active learning strategy was conducted, by iteratively incorporating poorly classified cases in the training set. After having been trained, the proposed system was experimented in continuous operation for unseen (out of sample) data, and the SVM detector obtained 97.7% and 98.7% of sensitivity and selectivity, respectively. The same type of ANN presented 88.4 % and 99.4% of sensitivity and selectivity when applied to data of a different seismic station of IM. © 2013 Springer-Verlag Berlin Heidelberg.
Resumo:
Thesis (Ph.D.)--University of Washington, 2016-02
Resumo:
This paper proposes a method for the design of gear tooth profiles using parabolic curve as its line of action. A mathematical model, including the equation of the line of action, the equation of the tooth profile, and the equation of the conjugate tooth profile, is developed based on the meshing theory. The equation of undercutting condition is derived from the model. The influences of the two design parameters, that present the size (or shape) of the parabolic curve relative to the gear size, on the shape of tooth profiles and on the contact ratio are also studied through the design of an example drive. The strength, including the contact and the bending stresses, of the gear drive designed by using the proposed method is analyzed by an FEA simulation. A comparison of the above characteristics of the gear drive designed with the involute gear drive is also carried out in this work. The results confirm that the proposed design method is more flexible to control the shape of the tooth profile by changing the parameters of the parabola.
Resumo:
Partindo do conceito de romance etnográfico utilizado no âmbito dos Estudos Literários e também Antropológicos, analisamos o romance histórico City of Broken Promises (1967), de Austin Coates, bem como a forma como a narrativa recorre a um variado número de temáticas antropológicas e estratégias literárias para representar os espaços e a vivência quotidiana das diversas comunidades (inglesa, portuguesa e chinesa) da Macau setecentista.
Resumo:
To boost logic density and reduce per unit power consumption SRAM-based FPGAs manufacturers adopted nanometric technologies. However, this technology is highly vulnerable to radiation-induced faults, which affect values stored in memory cells, and to manufacturing imperfections. Fault tolerant implementations, based on Triple Modular Redundancy (TMR) infrastructures, help to keep the correct operation of the circuit. However, TMR is not sufficient to guarantee the safe operation of a circuit. Other issues like module placement, the effects of multi- bit upsets (MBU) or fault accumulation, have also to be addressed. In case of a fault occurrence the correct operation of the affected module must be restored and/or the current state of the circuit coherently re-established. A solution that enables the autonomous restoration of the functional definition of the affected module, avoiding fault accumulation, re-establishing the correct circuit state in real-time, while keeping the normal operation of the circuit, is presented in this paper.