Genetic algorithm matched filter optimization for automated detection of blood vessels from digital retinal images

Due to the importance of the matched filter in the automated detection of blood vessels in digital retinal images, improving its response is highly desirable. This filter may vary in many ways depending on the parameters that govern its response. In this paper, new parameters to optimize the sensitivity of the matched filter are found using genetic algorithms on the test set of the DRIVE databases. The area under the receiver operating curve (ROC) is used as a fitness function for the genetic algorithm. To evaluate the improved matched filter, the maximum average accuracy (MAA) is calculated to be 0.9422 and the average area under ROC is 0.9582.     

A Constraint-Based Evolutionary Learning Approach to the Expectation Maximization for Optimal Estimation of the Hidden Markov Model for Speech Signal Modeling

This paper attempts to overcome the tendency of the expectation-maximization (EM) algorithm to locate a local rather than global maximum when applied to estimate the hidden Markov model (HMM) parameters in speech signal modeling. We propose a hybrid algorithm for estimation of the HMM in automatic speech recognition (ASR) using a constraint-based evolutionary algorithm (EA) and EM, the CEL-EM. The novelty of our hybrid algorithm (CEL-EM) is that it is applicable for estimation of the constraint-based models with many constraints and large numbers of parameters (which use EM) like HMM. Two constraint-based versions of the CEL-EM with different fusion strategies have been proposed using a constraint-based EA and the EM for better estimation of HMM in ASR. The first one uses a traditional constraint-handling mechanism of EA. The other version transforms a constrained optimization problem into an unconstrained problem using Lagrange multipliers. Fusion strategies for the CEL-EM use a staged-fusion approach where EM has been plugged with the EA periodically after the execution of EA for a specific period of time to maintain the global sampling capabilities of EA in the hybrid algorithm. A variable initialization approach (VIA) has been proposed using a variable segmentation to provide a better initialization for EA in the CEL-EM. Experimental results on the TIMIT speech corpus show that CEL-EM obtains higher recognition accuracies than the traditional EM algorithm as well as a top-standard EM (VIA-EM, constructed by applying the VIA to EM).     

Graphene oxide-coated microbottle resonators for relative humidity sensing

Graphene oxide (GO) is a 2D coating material used to improve fiber optics sensors’ response to relative humidity. Microbottle resonators (MBRs) have garnered more attention as sensing media structures. An MBR with a 190 µm diameter was coated with GO. Then, tapered fiber light coupling was used to investigate the relative humidity sensing performance in the range of 35—70%RH at 25 °C. The MBR showed a higher Q factor before and after GO coating. The sensitivity of 0.115 dB/%RH was recorded with the 190 µm GO-coated MBR sample compared to a sensitivity of 0.022 dB/%RH for the uncoated MBR sample. These results show that the MBR can be used in fiber optic sensing applications for environmental sensing.     

高速磨床整机动态特性研究

建立了某高速凸轮轴磨床整机的三维有限元模型,利用反求方法确定了结合部的基础参数,对整机进行了模态分析,初步确定了整机动态性能的薄弱环节,研究了结合部刚度参数对整机低阶模态的影响,提出了结构改进方案。建立径向基函数近似模型表征床身—工作台系统结合部刚度与其固有频率之间的隐式函数关系,通过对该系统进行模态实验测试,并与优化方法相结合,确定了该高速磨床床身工作台系统的结合部刚度参数。结果表明,该方法对整机建模和动力学性能的分析简单有效,增加垫板在床身上的约束可以有效地改善该高速磨床的动态特性。     

Previous experience affects subsequent anxiety-like responses in rats bred for novelty seeking.

Novelty-seeking behavior in rats is deemed to model sensation seeking in humans, a personality trait related to some psychiatric conditions, including substance abuse. Animals characterized based on their locomotor response to novelty, namely high and low responders (HRs and LRs, respectively), show differences in anxiety and drug-taking behaviors. This study evaluates the effect of anxiety-provoking situations on subsequent behaviors in these endophenotypes. Selectively bred HR and LR rats were submitted to blocks of tests consisting of two-trial light- dark (LD) and two-trial elevated plus maze (EPM) tests arranged in counterbalanced, alternating order. No differences in anxiety-like behaviors were found in HR-bred and LR-bred rats in either LD trial, regardless of the test order. Repeated exposure to the EPM test, however, resulted in enhanced behavioral response under different test orders as a function of endophenotype. Compared with HR-bred animals, LR-bred animals exhibited increased anxiety on reexposure to EPM but only if both trials were preceded by an LD test session. The emotional responses in HR-bred and LR-bred rats reported here may reflect different degrees of adaptive processing regulated by both genetic and environmental factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Technical note Proper utilization of solar energy in Bangladesh: effect on the environment, food supply and the standard of living

The only really sustainable form of energy is solar energy. The densely populated tropical countries can do very well from this completely sustainable energy source without any novel technologies. Most of the commercial energy used world-wide is supplied by using non-renewable resources. Environmental damage—global warming, ozone hole, noise, chemical and radioactive waste—is due to high energy use. Environmental deterioration is a direct consequence of wealth generated and sustained by extremely cheap fossil fuel. The price of fossil fuel does not include the cost for the deterioration of the environment. We show in this paper that even a densely populated country like Bangladesh can attain a high standard of living by a proper utilization of solar energy. We suggest that poor tropical countries should mobilize their resources to develop solar technology.     

An N-terminal region of LukF of staphylococcal leukocidin/gamma-hemolysin crucial for the biological activity of the toxin

The two staphylococcal bi-component toxins, leukocidin and gamma-hemolysin share LukF [Kamio et al, FEBS Lett., 321, 15-18 (1993)]. This report identifies the pivotal amino acid residues in the N-terminal region of LukF for the leukocytolytic and hemolytic activities in the presence of LukS and HIg2, respectively, measuring the toxin activity of a series of LukF mutants with truncated N-terminals. The data obtained showed that the LukF mutant TF21, lacking 20 amino acid residues at the N-terminus of LukF, failed to have any hemolytic activity and had less 10% leukocytolytic activity than that of the intact LukF, while 16-residue truncations retained both toxin activities without loss. The LukF mutants lacking 18- through 19-residue segments from the N-terminus showed low toxin activity on both target cells. All mutants having no toxin activity were also not capable of binding to the human erythrocytes. It can thus be concluded that the 3-residue segment, L18Y19K20 of LukF is crucial for the biological activity of the toxin.     

Development and testing of analytical models for the pebble bed type HTRs

The pebble bed type gas cooled high temperature reactor (HTR) appears to be a good candidate for the next generation nuclear reactor technology. These reactors have unique characteristics in terms of the randomness in geometry, and require special techniques to analyze their systems. This study includes activities concerning the testing of computational tools and the qualification of models. Indeed, it is essential that the validated analytical tools be available to the research community. From this viewpoint codes like MCNP, ORIGEN and RELAP5, which have been used in nuclear industry for many years, are selected to identify and develop new capabilities needed to support HTR analysis. The geometrical model of the full reactor is obtained by using lattice and universe facilities provided by MCNP. The coupled MCNP-ORIGEN code is used to estimate the burnup and the refuelling scheme. Results obtained from Monte Carlo analysis are interfaced with RELAP5 to analyze the thermal hydraulics and safety characteristics of the reactor. New models and methodologies are developed for several past and present experimental and prototypical facilities that were based on HTR pebble bed concepts. The calculated results are compared with available experimental data and theoretical evaluations showing very good agreement. The ultimate goal of the validation of the computer codes for pebble bed HTR applications is to acquire and reinforce the capability of these general purpose computer codes for performing HTR core design and optimization studies.     

Microbial Fuel Cell Membrane Bioreactor in Wastewater Treatment,Electricity Generation and Fouling Mitigation

Membrane bioreactors (MBR) have gained much attention due to their ability to achieve higher treatment efficiency. However, high external energy consumption in aeration for membrane fouling mitigation has been limiting their application. Microbial fuel cells (MFC) can ideally extract energy from wastewater in the form of electricity and reduce membrane fouling. Thus, the use of MFC-MBR is rapidly expanding. However, the MFC-MBR design and operation is not fully mature and further research is needed to optimize the process efficiency and enhance the applicability. This review gives an overview of recent studies on the performances of MFC-MBR systems, regarding the design and configuration of the integrated system, irrespective of whether optimization was done or not in the operating system.