Automated detection of proliferative diabetic retinopathy using a modified line operator and dual classification

Proliferative diabetic retinopathy (PDR) is a condition that carries a high risk of severe visual impairment. The hallmark of PDR is neovascularisation, the growth of abnormal new vessels. This paper describes an automated method for the detection of new vessels in retinal images. Two vessel segmentation approaches are applied, using the standard line operator and a novel modified line operator. The latter is designed to reduce false responses to non-vessel edges. Both generated binary vessel maps hold vital information which must be processed separately. This is achieved with a dual classification system. Local morphology features are measured from each binary vessel map to produce two separate feature sets. Independent classification is performed for each feature set using a support vector machine (SVM) classifier. The system then combines these individual classification outcomes to produce a final decision. Sensitivity and specificity results using a dataset of 60 images are 0.862 and 0.944 respectively on a per patch basis and 1.00 and 0.90 respectively on a per image basis.     

A parametrisation for dissipative behaviours–the matrix case

We study linear, time-invariant dynamical systems that are dissipative with respect to a generalised power defined by a quadratic differential form. We address several cases, in an increasing order of complexity, and show how dissipative systems can be parametrised. In this process, we also establish a number of results for polynomial matrices that are of independent interest. The present article is a generalisation of our earlier work that dealt with single-input single-output dissipative systems (Pendharkar, I., and Pillai, H.K. (2004), ‘A Parametrization for Dissipative Behaviours’, Systems and Control Letters, 51, 123–132).     

Application of BT and PC-BT in Homo sapiens gene prediction

Digital signal processing is gaining popularity in gene classification and prediction. Spectral content of gene is estimated using Blackman–Tukey (BT) method for identification of Homo sapiens cancer genes. A data reduction method; principal component analysis (PCA) is used prior to Blackman–Tukey method (PC-BT) for better identification of genes. Selection of proper model order is prime important in PCA method for considering the number of principal components (PCs) and the performance of the method depends on optimal selection of PCs. Cumulative percent variance and scree test residual percent variance are used as measurement metric for selection of PCs. Quality factor is used to judge the performance of the estimators. Simulation results show the clarity of spectrum plot in PC-BT method is 200 % higher than BT method. The spectral peaks observed in cancer genes are used to screen out cancer genes from healthy genes. The methods are successfully tested on breast, prostate and colon Homo sapiens. Healthy and cancer Homo sapiens genes are downloaded from Cancer Genome Anatomy Project (CGAP) site and National Centre for Biotechnology Information (NCBI) site.     

Study of enhanced DC and analog/radio frequency performance of a vertical super-thin body FET by high-k gate dielectrics

This article reports the DC and analog/radio frequency (RF) response of a newly invented device called vertical super-thin body (VSTB) FET towards high-k (Si₃N₄/HfO₂) and low-k (SiO₂) gate dielectrics in conjunction with the scaling effect through a well-calibrated Sentaurus TCAD tool. At channel length (L_G) of 20 nm, compared to SiO₂, Si₃N₄ improves various DC parameters such as off-state leakage current (I_off), on-current (I_on), on-to-off current ratio (I_on/I_off ratio), subthreshold swing (SS), and drain-induced-barrier-lowering (DIBL) by 77.15%, 26.2%, one order of magnitude, 15.78%, and 36.2%, respectively. On the other hand, a higher improvement is seen in all these DC parameters for the HfO₂ gate dielectric (I_off, I_on, I_on/I_off ratio, SS, DIBL improves respectively by 91.8%, 41.57%, two orders of magnitude, 28.28%, and 62.71%). The underlying physics behind such excellent improvement is explained by the device off-state energy band diagram, electrostatic potential, and channel electron density profile for each dielectric. Further, for all the gate dielectrics considered, the device characteristics were studied for a wide range of L_G from 10 to 50 nm to reveal the scaling impact on the device performance. Irrespective of the gate dielectric material, the device exhibits excellent performance at L_G = 10 nm, which in turn indicates to the brilliant scalability of this new device. Besides, although Si₃N₄ and HfO₂ increase gate capacitance (C_gg)/gate-drain capacitance (C_gd), due to the extremely low values of C_gg/C_gd, enhanced unit gain cut-off frequency, and gain-bandwidth-product is achieved. In addition, the increased transconductance (g_m) of the device applying Si₃N₄/HfO₂ gate dielectric leads to a higher peak value of TGF, intrinsic gain, TFP, GFP, and GTFP. This study intends to expand the fundamental knowledge about such a new device as a VSTB FET and hence, aims to be utilized in the future research of this novel device.     

Comparative Studies of Different Methods for Determining Crystallization Kinetics of Metallic Glass

Different non-isothermal and isothermal techniques are used to find out the phase transformation kinetic parameters (in this case, activation energy [E] of crystallization, Avrami exponent [n] and frequency factor [k ₀]) for the crystallization of a newly developed four component Zr₅₈Cu₂₂Al₁₂Ag₈ glassy alloy using differential scanning calorimetry (DSC) data. A comparative study is carried out to understand the effectiveness of different methods of evaluation of crystallization kinetic parameters from the DSC traces. n for the alloy varies in the range of 2.5?C4 suggesting that growth varies from one to three dimensional with growth mechanism varying from diffusion controlled 3D growth to an interface controlled 1D growth.     

Classification of caudal ventrolateral pontine neurons with sympathetic nerve-related activity

This study was designed to answer three questions concerning caudal ventrolateral pontine (CVLP) neurons whose naturally occurring discharges are correlated to sympathetic nerve discharge (SND). 1) What are the proportions of CVLP neurons that have activity correlated to both the cardiac-related and 10-Hz rhythms in SND, to only the 10-Hz rhythm, and to only the cardiac-related rhythm? 2) Do CVLP neurons with activity correlated to the cardiac-related and/or 10-Hz rhythm in SND subserve a sympathoexcitatory or sympathoinhibitory function? 3) Do CVLP neurons with activity correlated to the cardiac-related and/or 10-Hz rhythm in SND project to the thoracic spinal cord? To address these issues we recorded from 476 CVLP neurons in 24 urethan-anesthetized cats. Spike-triggered averaging, arterial pulse-triggered analysis, and coherence analysis revealed that the discharges of 66 of these neurons were correlated to inferior cardiac postganglionic SND. For 39 of these neurons, we were able to determine whether their discharges were correlated to one or both rhythms. The results showed that the CVLP contained a heterogeneous population of neurons with sympathetic nerve-related activity. The discharges of 21 neurons were correlated to both the 10-Hz and cardiac-related rhythms in SND, 9 neurons had activity correlated to only the 10-Hz rhythm, and 9 neurons had activity correlated to only the cardiac-related rhythm. The firing rates of CVLP neurons with activity correlated to both rhythms or to only the 10-Hz rhythm were decreased during the inhibition of SND induced by baroreceptor reflex activation (rapid obstruction of the abdominal aorta). These neurons are presumed to exert sympathoexcitatory actions. The time-controlled collision test verified that 11 of 12 CVLP neurons with activity correlated to both rhythms were antidromically activated by stimulation of the first thoracic segment of the spinal cord. Antidromic mapping at this level showed that the site requiring the least stimulus current to elicit the longest latency response (nearest the terminal) was in the vicinity of the intermediolateral nucleus (IML). In contrast, only 1 of 13 CVLP neurons with activity correlated to only one of the rhythms in SND could be antidromically activated by spinal stimulation. These data demonstrate for the first time that there is a direct pathway from the CVLP to the IML that is comprised almost exclusively of sympathoexcitatory neurons whose discharges are correlated to both the 10-Hz and cardiac-related rhythms in SND.     

Mathematical Model Development of Raceway Parameters and Their Effects on Corex Process

  Corex is an alternative ironmaking process and raceway is one of the important areas to maintain the stability of the furnace. The raceway parameters are well established for blast furnace operation. But for Corex process, it has not yet been established and optimized. Thus, a mathematical model was developed to determine various raceway parameters such as RAFT (raceway adiabatic flame temperature), tuyere gas velocity and kinetic energy. The model provides an idea about the raceway geometry, zone temperature and kinetic energy accumulated in tuyere gas. Besides, all the raceway parameters have been analyzed to find out their effects on the Corex process. It is found that RAFT influences the gasification reaction kinetics and higher RAFT generates more CO in reduction gas, which improves the metallisation degree of the DRI in shaft. It is also found that increased gas velocity and kinetic energy generate more fines and demand more coke to maintain char bed permeability. High coke rate increases the production cost and lowers the production of hot metal.     

Theoretical and numerical investigations of an electroosmotic flow micropump with interdigitated electrodes

In this work, an electroosmotic flow micropump is proposed and investigated using theoretical analysis and numerical simulations. The micropump comprises an array of interdigitated electrodes on the top and the bottom surfaces of a rectangular microchannel. Theoretical analysis and extensive numerical simulations are performed to predict the pressure-flow characteristics of the micropump. The results of the model and simulations are compared which show good agreement with each other. The effects of various geometrical parameters including spacing between a pair of electrodes, gap between adjacent pairs of electrodes, width and height of the electrodes, and width of the microchannel and operating parameter including applied voltage on the performance of the micropump in terms of flow and pressure capacity is investigated.     

Silt: A distributed bit-parallel architecture for early vision

A new form of parallelism,distributed bit-parallelism, is introduced. A DBP organization distributes each bit of a data item to a different processor. DBP allows computation that is sublinear with word size for such operations as integer addition, arithmetic shifts, and data moves. The implications of DBP for system architecture are analyzed. An implementation of a DPB architecture based on a mesh with a fost-bypass network is presented, and the performance of DBP algorithms on this architecture is analyzed. The application of the architecture to early vision algorithms is discussed.     

Compact and power efficient SEC-DED codec for computer memory

Microsystem Technologies - Frequently, soft errors occur due to striking of radioactive particles in memory cells which reduce the reliability of memory systems. Generally, single error...