A top-down quadtree traversal algorithm

Many standard image processing operations can be implemented using quadtrees as a simple tree traversal where, at each terminal node, a computation is performed involving some of that node's neighbors. Most of this work has involved the use of bottom-up neighbor-finding techniques which search for a nearest common ancestor. Recently, top-down techniques have been proposed which make use of a neighbor vector as the tree is traversed. A simplified version of the top-down method for a quadtree in the context of a general-purpose tree traversal algorithm is presented. It differs, in part, from prior work in its ability to compute diagonally adjacent neighbors rather than just horizontally and vertically adjacent neighbors. It builds a neighbor vector for each node using a minimal amount of information. Analysis of the algorithm shows that its execution time is directly proportional to the number of nodes in the tree. However, it does require some extra storage. Use of the algorithm leads to lower execution time bounds for some common quadtree image processing operations such as connected component labeling.     

Flow-injection electrochemical determination of glucose by a poly[1-(2-aminophenyl) pyrrole] modified gold electrode

Poly[1-(2-aminophenyl) pyrrole] film was electropolymerized on a gold electrode and used for the first time as the matrix for the electrochemical determination of glucose. The working electrode where glucose oxidase was chemically immobilized by amine groups of the poly[1-(2-aminophenyl) pyrrole] film was used for online glucose determination with flow-injection operation. The optimum conditions for glucose were a flow rate of 4?mL/min at +0.7?V in 100?mM using pH 6.5 phosphate buffer as the carrier. The electrode provided a long linear dynamic range between 0.2?mM and 30?mM, a response time of 9?s, a detection limit of 63?µM, a relative standard deviation of 0.7%, and an accuracy of 99.95%. The working electrode preserved 64% of its initial current value following six weeks. The optimized device was employed to determine glucose in wastewater from the Zonguldak Biological Treatment Plant, Turkey.     

Colocalization of MCM8 and MCM7 with proteins involved in distinct aspects of DNA replication

Minichromosome maintenance (MCM) proteins are essential for DNA replication in eukaryotes. A subcomplex of the MCM2-7 family members, initially characterized in yeast, is thought to serve as a eukaryotic DNA replicative helicase. MCM8 is a new family member, not present in yeast, which may function alone or with other family members in aspects of DNA metabolism, including replication initiation and elongation. Through the use of chromatin immunoprecipitation, we find that MCM8, like MCM7, colocalizes on a specific DNA segment of the c-MYC replication initiation zone (c-MYC replicator) with Cdc6, a protein potentially involved in loading MCM proteins onto DNA. The association between MCM8 and MCM7 peaks in mid G1, at the time of assembly of the prereplication complex. The association of both MCM proteins with Cdc6, however, continues even after DNA replication is complete. We also find that MCM8 colocalizes at the c-MYC replicator with chromatin-bound Cdk2. Our data indicate that any role MCM8 may play in elongation is likely to be discontinuous, in its association with DNA, from a potential role in initiation. Using immunogold electron microscopy we show that MCM8 and MCM7 differ in spatial relation to RPA70 during S phase. Our data strongly suggest that MCM8 functions with other known replication proteins in processes which accompany DNA replication, especially initiation, and which are specifically adapted to suit higher eukaryotes.     

Carbonaceous Materials-12: a Novel Highly Sensitive Graphene Oxide-Based Carbon Electrode: Preparation,Characterization, and Heavy Metal Analysis in Food Samples

Graphene oxide (GO) was covalently attached to glassy carbon (GC) electrode (GC–O–GO) for fabricating nanosensors to determine trace Pb²⁺ and Cd²⁺ using differential pulse anodic stripping voltammetry (DPASV). Surface characterization of the nanofilm-covered electrode was performed via electrochemical cyclic voltammetry (CV), transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. Surface pKa of the GO covalent attached GC (GC–O–GO) was calculated via CV. Under optimal conditions, a linear response was found for Pb²⁺ and Cd²⁺ in the range from 1?×?10^?8 to 1?×?10^?12 M. The limit of detections (LODs) of Pb²⁺ and Cd²⁺ were 0.25 pM and 0.28 pM, respectively. The method shows good reproducibility, and stability was successfully applied to measure Pb²⁺ and Cd²⁺ levels in rice, soya, milk, and tap water samples, with good agreement with those obtained by the standard inductively coupled plasma optical emission spectrometry (ICP-OES) method. The method was evaluated by application with the simultaneous determination of the ions in food samples (n?=?6) using the standard addition method. The recoveries of the Pb²⁺ and Cd²⁺ were up to 98 %.     

Implementation and Optimization of an Enhanced PWD Metric for H.264/AVC on a TMS320C64 DSP

A common method for selecting the best prediction mode based on block matching algorithm is to compare, for each source block, the associated distortions among the available prediction candidates. The human visual perception is sensitive to luminance contrast rather than absolute luminance values. In fact, the human eyes ability to detect the magnitude difference between an object and its background depends on the background luminance average value. The Perceptually Weighted Distortion (PWD) is a new distortion measure that can produce better image quality. In this paper, we propose to add a new feature to the PWD by introducing another diagonal component that yields to a significant quality improvement. The enhanced PWD metric actually outperforms the original PWD and the SAD metric, according to the experimental results, especially in the aspect of reducing block artifacts. An increase in terms of implementation complexity will be noticed as a result of this contribution. Therefore, optimized implementation of the Enhanced PWD exploiting the C64 DSP-Core assets will be presented. In fact, Standard Assembly (SA) is used to implement the different Enhanced PWD functions in order to exploit efficiently the C64 internal architecture and resources. Experimental results show more than 85% improvement in terms of cycle cost compared to C code.     

Ultrasound monitoring of bubble size and velocity in a fluid model using phased array transducer

Experimental studies on composite materials highlighted the existence of gas bubbles (voids) at different scales (micro and macro). These voids, resulting from the fabrication process, are sources of weakness for the end-user material. Therefore, several studies focus on the evaluation and the minimization of void rate. During injection of resin into the fibrous matrix, bubbles appear. Some are dispersed while others persist and diminish the overall quality of the finished product. This study consists in detecting bubbles during the resin transfer molding (RTM) process using an original method based on ultrasound. However, in practice we have to face with several problems due to the heterogeneity of the environment, such as the differentiation of a bubble from a strand or fiber. Due to the complexity of the problem, an experimental setup was built in order to detect bubbles using an ultrasonic phased array transducer in a flow of viscous fluid only, without the presence of fiber matrix. The study deals with the flow of a model fluid, which simulates the injected resin, with presence of air bubbles trapped in a channel production. Since the ultrasonic characteristics of the experimental setup are well known and characterized, the number, velocity and size of air bubbles could be evaluated.     

Estimation of highly selective channels for OFDM system by complex least squares support vector machines

A channel estimator using complex least squares support vector machines (LS-SVM) is proposed for pilot-aided OFDM system and applied to Long Term Evolution (LTE) downlink. This channel estimation algorithm use knowledge of the pilot signals to estimate the total frequency response of the channel. Thus, the algorithm maps trained data into a high dimensional feature space and uses the structural risk minimization (SRM) principle, which minimizes an upper bound on the generalization error, to carry out the regression estimation for the frequency response function of the highly selective channel. Simulation results show that the proposed method has better performance compared to the conventional LS and Decision Feedback methods and it is more robust at high speed mobility.     

New design of 3.2–4.8 GHz generator for multi-bands architecture of UWB communication

In this paper a new design of Ultra-Wide Band (UWB) generator is presented. This circuit is the most important block in multi-bands transmitter architecture of UWB communication system. The proposed UWB generator is composed of multi-bands voltage controlled oscillator (VCO), mixer and rectangular pulse generator which consist of ring oscillator, time delay and AND gate function. The UWB generator is based on multiplying the rectangular pulse envelope to a continuous sinusoidal wave in order to generate the UWB signal. This UWB generator circuit produces an output signal which is characterized by the bandwidth of 1600 MHz divided into three sub-bands of 528 MHz, centered at frequencies of 3.432, 3.96, 4.488 GHz and the limited Power Spectral Density (PSD) is −41.44 dBm/MHz. The maximum amplitude of UWB signal is 214 mV, the pulse is during of 3 ns and the pulse repetition period (PRP) is 32 ns. The power consumption is approximately equal to 26 mW at a voltage supply of 2.5 V. This topology is designed in CMOS 0.35 μm AMS process technology.     

Determination of the residual monomer concentration of ε-caprolactam in polyamide-6 using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy gas analysis

For the anionic polymerization of ε-caprolactam to polyamide-6 the residual monomer concentration in the final polymer is an important characteristic. To determine this residual ε-caprolactam monomer concentration, a fast and fail-safe method was developed, which couples thermogravimetric analysis (TGA) with Fourier transform infrared spectroscopy (FTIR) gas analysis. FTIR allows an identification of the types of gasses released during heat treatment. Calibration of the infrared absorbance of ε-caprolactam and the corresponding mass loss in TGA allows a quantitative evaluation of the ε-caprolactam monomer release. Low-heating rates and powdery samples guarantee high-precision measurements.