Chaotic synchronization in general network topology for scene segmentation

Chaotic synchronization has been discovered to be an important property of neural activities, which in turn has encouraged many researchers to develop chaotic neural networks for scene and data analysis. In this paper, we study the synchronization role of coupled chaotic oscillators in networks of general topology. Specifically, a rigorous proof is presented to show that a large number of oscillators with arbitrary geometrical connections can be synchronized by providing a sufficiently strong coupling strength. Moreover, the results presented in this paper not only are valid to a wide class of chaotic oscillators, but also cover the parameter mismatch case. Finally, we show how the obtained result can be applied to construct an oscillatory network for scene segmentation.

Chaotic synchronization in 2D lattice for scene segmentation

Synchronization and chaos play important roles in neural activities and have been applied in oscillatory correlation modeling for scene and data analysis. Although it is an extensively studied topic, there are still few results regarding synchrony in locally coupled systems. In this paper we give a rigorous proof to show that large numbers of coupled chaotic oscillators with parameter mismatch in a 2D lattice can be synchronized by providing a sufficiently large coupling strength. We demonstrate how the obtained result can be applied to construct an oscillatory network for scene segmentation. (C) 2007 Elsevier B.V. All rights reserved.

An entropy-based approach to automatic image segmentation of satellite images

An entropy-based image segmentation approach is introduced and applied to color images obtained from Google Earth. Segmentation refers to the process of partitioning a digital image in order to locate different objects and regions of interest. The application to satellite images paves the way to automated monitoring of ecological catastrophes, urban growth, agricultural activity, maritime pollution, climate changing and general surveillance. Regions representing aquatic, rural and urban areas are identified and the accuracy of the proposed segmentation methodology is evaluated. The comparison with gray level images revealed that the color information is fundamental to obtain an accurate segmentation. (C) 2010 Elsevier B.V. All rights reserved.

Cross-situational learning of object-word mapping using Neural Modeling Fields

The issue of how children learn the meaning of words is fundamental to developmental psychology. The recent attempts to develop or evolve efficient communication protocols among interacting robots or Virtual agents have brought that issue to a central place in more applied research fields, such as computational linguistics and neural networks, as well. An attractive approach to learning an object-word mapping is the so-called cross-situational learning. This learning scenario is based on the intuitive notion that a learner can determine the meaning of a word by finding something in common across all observed uses of that word. Here we show how the deterministic Neural Modeling Fields (NMF) categorization mechanism can be used by the learner as an efficient algorithm to infer the correct object-word mapping. To achieve that we first reduce the original on-line learning problem to a batch learning problem where the inputs to the NMF mechanism are all possible object-word associations that Could be inferred from the cross-situational learning scenario. Since many of those associations are incorrect, they are considered as clutter or noise and discarded automatically by a clutter detector model included in our NMF implementation. With these two key ingredients - batch learning and clutter detection - the NMF mechanism was capable to infer perfectly the correct object-word mapping. (C) 2009 Elsevier Ltd. All rights reserved.

Minimum cycle cover and Chinese postman problems on mixed graphs with bounded tree-width

Let M = (V, E, A) be a mixed graph with vertex set V, edge set E and arc set A. A cycle cover of M is a family C = {C(1), ... , C(k)} of cycles of M such that each edge/arc of M belongs to at least one cycle in C. The weight of C is Sigma(k)(i=1) vertical bar C(i)vertical bar. The minimum cycle cover problem is the following: given a strongly connected mixed graph M without bridges, find a cycle cover of M with weight as small as possible. The Chinese postman problem is: given a strongly connected mixed graph M, find a minimum length closed walk using all edges and arcs of M. These problems are NP-hard. We show that they can be solved in polynomial time if M has bounded tree-width. (C) 2008 Elsevier B.V. All rights reserved.

Cytotoxic and genotoxic effects of tambjamine D, an alkaloid isolated from the nudibranch Tambja eliora, on Chinese hamster lung fibroblasts

Marine organisms have been shown to be potential sources of bioactive compounds with pharmaceutical applications. Previous chemical investigation of the nudibranch Tambja eliora led to the isolation of the alkaloid tambjamine D. Tambjamines have been isolated from marine sources and belong to the family of 4-methoxypyrrolic-derived natural products, which display promising immunosuppressive and cytotoxic properties. Their ability to intercalate DNA and their pro-oxidant activity may be related to some of the biological effects of the 4-methoxypyrrolic alkaloids. The aim of the present investigation was to determine the cytotoxic, pro-oxidant and genotoxic properties of tambjamine D in V79 Chinese hamster lung fibroblast cells. Tambjamine D displayed a potent cytotoxic effect in V79 cells (IC50 1.2 mu g/mL) evaluated by the MTT assay. Based on the MTT result, V79 cells were treated with different concentrations of tambjamine D (0.6. 1.2. 2.4 and 4.8 mu g/mL). After 24 h, tambjamine D reduced the number of viable cells in a concentration-dependent way at all concentrations tested. assessed by the trypan blue dye exclusion test. The hemolytic assay showed that the cytotoxic activity of tambjamine D was not related to membrane disruption (EC50 > 100 mu g/mL). Tambjamine D increased the number of apoptotic cells in a concentration-dependent manner at all concentrations tested according to acridine orange/ethidium bromide staining, showing that the alkaloid cytotoxic effect was related to the induction of apoptosis. MTT reduction was stimulated by tambjamine D, which may indicate the generation of reactive oxygen species. Accordingly, treatment of cells with tambjamine D increased nitrite/nitrate at all concentrations and TBARS production starting at the concentration corresponding to the IC50. Tambjamine D, also, induced DNA strand breaks and increased the micronucleus cell frequency as evaluated by comet and micronucleus tests, respectively, at all concentrations evaluated. showing a genotoxic risk induced by tambjamine D. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Fingerprint Segmentation

In this thesis, a new algorithm has been proposed to segment the foreground of the fingerprint from the image under consideration. The algorithm uses three features, mean, variance and coherence. Based on these features, a rule system is built to help the algorithm to efficiently segment the image. In addition, the proposed algorithm combine split and merge with modified Otsu. Both enhancements techniques such as Gaussian filter and histogram equalization are applied to enhance and improve the quality of the image. Finally, a post processing technique is implemented to counter the undesirable effect in the segmented image. Fingerprint recognition system is one of the oldest recognition systems in biometrics techniques. Everyone have a unique and unchangeable fingerprint. Based on this uniqueness and distinctness, fingerprint identification has been used in many applications for a long period. A fingerprint image is a pattern which consists of two regions, foreground and background. The foreground contains all important information needed in the automatic fingerprint recognition systems. However, the background is a noisy region that contributes to the extraction of false minutiae in the system. To avoid the extraction of false minutiae, there are many steps which should be followed such as preprocessing and enhancement. One of these steps is the transformation of the fingerprint image from gray-scale image to black and white image. This transformation is called segmentation or binarization. The aim for fingerprint segmentation is to separate the foreground from the background. Due to the nature of fingerprint image, the segmentation becomes an important and challenging task. The proposed algorithm is applied on FVC2000 database. Manual examinations from human experts show that the proposed algorithm provides an efficient segmentation results. These improved results are demonstrating in diverse experiments.

Chinese Basic Pension Substitution Rate: A Monte Carlo Demonstration of the Individual Account Model

At the end of 2005, the State Council of China passed ”The Decision on adjusting the Individual Account of Basic Pension System”, which adjusted the individual account in the 1997 basic pension system. In this essay, we will analyze the adjustment above, and use Life Annuity Actuarial Theory to establish the basic pension substitution rate model. Monte Carlo simulation is also used to prove the rationality of the model. Some suggestions are put forward associated with the substitution rate according to the current policy.

Color Segmentation using LVQ-Learning Vector Quantization

This thesis aims to present a color segmentation approach for traffic sign recognition based on LVQ neural networks. The RGB images were converted into HSV color space, and segmented using LVQ depending on the hue and saturation values of each pixel in the HSV color space. LVQ neural network was used to segment red, blue and yellow colors on the road and traffic signs to detect and recognize them. LVQ was effectively applied to 536 sampled images taken from different countries in different conditions with 89% accuracy and the execution time of each image among 31 images was calculated in between 0.726sec to 0.844sec. The method was tested in different environmental conditions and LVQ showed its capacity to reasonably segment color despite remarkable illumination differences. The results showed high robustness.

Evaluation of Red Colour Segmentation Algorithms in Traffic Signs Detection

Colour segmentation is the most commonly used method in road signs detection. Road sign contains several basic colours such as red, yellow, blue and white which depends on countries.The objective of this thesis is to do an evaluation of the four colour segmentation algorithms. Dynamic Threshold Algorithm, A Modification of de la Escalera’s Algorithm, the Fuzzy Colour Segmentation Algorithm and Shadow and Highlight Invariant Algorithm. The processing time and segmentation success rate as criteria are used to compare the performance of the four algorithms. And red colour is selected as the target colour to complete the comparison. All the testing images are selected from the Traffic Signs Database of Dalarna University [1] randomly according to the category. These road sign images are taken from a digital camera mounted in a moving car in Sweden.Experiments show that the Fuzzy Colour Segmentation Algorithm and Shadow and Highlight Invariant Algorithm are more accurate and stable to detect red colour of road signs. And the method could also be used in other colours analysis research. The yellow colour which is chosen to evaluate the performance of the four algorithms can reference Master Thesis of Yumei Liu.

A Linguistic Analysis of the Written Production of Second Language Learners : The Variation of Article Usage by Adult Chinese Learners of English

This study aims to test Robertson’s lexical transfer principle, which posits that Chinese learners use demonstratives (particularly this) and the numeral one as markers of definiteness and indefiniteness. This is tested by analysing Chinese learners’ written production collected from the Spoken and Written English Corpus of Chinese Learners 2.0 (SWECCL 2.0). The purpose is to understand the variation of article usage by adult Chinese learners of English. More specifically, the study examines to what extent articles, possessive and demonstrative pronouns are used in Chinese learners’ English and how definite and indefinite articles are used by the Chinese learners. Findings suggest that Robertson’s lexical transfer principle was corroborated by the present study. In addition, Chinese learners prefer to use demonstrative determiners, the possessive determiner our, and the numeral one to perform the function of marking definiteness and indefiniteness. In particular, the learners try to use the demonstrative determiners that and this in the anaphoric function instead of the definite article, and the demonstrative determiner those is frequently used in the cataphoric function. What is more, the learners use the numeral one as a marker of indefiniteness, and it is also used as a marker of definiteness in the anaphoric function. Further, the possessive determiner our is used as a marker of definiteness in larger situation uses referring to something unique. To this end, the study is able to show that the definite article is used to perform the function of marking indefiniteness, and in some particular contexts the definite article functions as a Chinese specifier in Chinese learners’ English. Also, the indefinite article is frequently used in quantifier phrases but is rarely used in other functions. There are three main reasons that may explain why Chinese learners use determiners variously. Firstly, the choice of determiners by Chinese learners is influenced by linguistic contexts. Secondly, because of learning strategies, Chinese learners try to ignore the anaphoric function and cataphoric function that they are not yet ready to process in article usage. Thirdly, interlanguage grammar influences the optionality in the use of articles.