Signal Adaptive Pipelined Hardware Design of Time-Varying Optimal Filter for Highly Nonstationary FM Signal Estimation

In this paper we develop a multiple-clock-cycle signal adaptive hardware design of an optimal nonstationary (time-varying) filtering system. The proposed design is based on the real-time results of time-frequency (TF) analysis and the estimation of instantaneous frequency (IF). It permits multiple detection of the local filter’s region of support (FRS) in the observed increment of time, resulting in the efficient filtering of multicomponent frequency modulated (FM) signals. The proposed design takes a variable number of clock (CLK) cycles–the only necessary ones regarding the highest quality of IF estimation–in different TF points within the execution. In this way it allows the implemented system to optimize the computational cost, as well as the time required for execution. Further, the proposed serial design optimizes critical design performances, related to the hardware complexity, making it a suitable system for real-time implementation on an integrated chip. Also, by applying the pipelining technique, it allows overlapping between different TF points within the execution, additionally improving the time required for time-varying filtering. The design has been verified by a field-programmable gate array (FPGA) circuit design, capable of performing filtering of nonstationary FM signals in real-time.     

Intracellular imaging of Qdots‐labeled DNA in cyanobacteria

In this contribution, they have attempted to develop a labeling technique for in vivo imaging of functionally active plasmid DNA in cyanobacterial cells through its decoration with semiconductor quantum dots (Qdots) as fluorescent nanoprobes. For that purpose biotinylated plasmid slr2060 DNA was conjugated with Qdots‐streptavidine. The intact DNA was visualized in a single green color by light microscopy. These Qdots‐DNA conjugates were capable of expressing the acyltransferase enzyme. Qdots‐DNA conjugates and confocal microscope imaging technique were adopted to visualize the gene transport across the membrane of the live cyanobacteria cell in real time. Long‐term kinetic study enabled to reveal the steps of extracellular and intracellular microenvironment for plasmid transportation into the live cell. To confirm these processes a confocal microscope and indicator plate assay test were applied in tandem. In this contribution, Qdots‐labeled plasmid DNA was utilized for the first time for long‐term intracellular imaging studies in cyanobacteria species PCC6803. The results showed that the Qdots‐labeled plasmid DNA detection could be used as a powerful labeling technique for visualization of exogenous DNA entry and tracking into living cells by confocal microscopy. Microsc. Res. Tech. 79:447–452, 2016. © 2016 Wiley Periodicals, Inc.     

Biodegradation dynamics of high catechol concentrations by Aspergillus awamori

The biodegradation process of high catechol concentrations by Aspergillus awamori was investigated. The values of the kinetic constants for a model of specific growth rate at different initial conditions were determined. At 1.0 g/L catechol concentration, the biodegradation process proceeded in the conditions of substrate limitation. At higher catechol concentrations (2.0 and 3.0 g/L) a presence of substrate inhibition was established. The dynamics of the specific catechol degradation rate was studied and the values of catechol and biomass concentrations, maximizing the specific catechol degradation rate, were estimated analytically. The specified ratio catechol/biomass could serve as a starting base for determination of the initial conditions for a batch process, for specifying the moment of feeding for a fed-batch process, and for monitoring and control of a continuous process by the aim of time-optimal control.     

Unified approach to noise analysis in the Wigner distribution and spectrogram

An analysis of time-frequency representations of noisy signals is performed. Using the method for time-frequency signal analysis which was recently defined by Stankovic (the S-method), the influence of noise on the two most important distributions (spectrogram and Wigner distribution) is analyzed in unified manner. It is also shown that, for signals whose instantaneous frequency is not constant, an improvement over the spectrogram and the Wigner distribution performances in a noisy environment may be achieved using the S-method. The expressions for mean and variance are derived. Results are given for several illustrative and numerical examples.     

Mobile Web services authentication using SAML and 3GPP generic bootstrapping architecture

In this paper we present a platform for the direct consumption of web services by a Mobile Station. We give an architectural solution where Mobile Operators play the role of Trusted Third Parties supplying service credentials that allow a co-located 3GPP Network Application Function and Liberty-enabled Identity Provider entity to implement a controlled Shopping Mall service to Mobile Stations from multiple trust domains. We consider both the protocol and the structure and syntax of the various tokens required to minimise service latency over the bandwidth and performance constrained mobile system, whilst providing adequate security services to protect against the perceived threat model. To validate our proposal we have developed code to create a Web Service test scenario using SAML authentication tokens utilising readily available J2ME, Java Card, J2SE and J2EE platforms, Web Services tools from Apache, the KToolBar emulator from Sun, and the JCOPS suite of tools for Java Card applet development.     

Application-aware scheduling for VoIP in Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are seen as a means to provide last mile connections in Next Generation Networks (NGNs). Because of their auto-configuration capabilities and the low deployment cost WMNs are considered to be an efficient solution for the support of multiple voice, video and data services in NGNs. This paper looks at the optimal provision of resources in WMNs for Voice over IP (VoIP) traffic, which has strict performance requirements in terms of delay, jitter and packet loss. In WMNs, because of the challenges introduced by wireless multi-hop transmissions and limited resources, providing performance quality for VoIP comparable to the voice quality in the traditional circuit-switched networks is a major challenge.This paper analyses different scheduling mechanisms for TDMA-based access control in mesh networks as specified in the IEEE 802.16-2004 WiMAX standard. The performance of the VoIP applications when different scheduling mechanisms are deployed is analysed on a variety of topologies using ns-2 simulation and mathematical analysis. The paper concludes that on-demand scheduling of VoIP traffic – typically deployed in 802.11-based WMNs – is not able to provide the required VoIP quality in realistic mesh WiMAX network scenarios and is therefore not optimal from a network operator’s point of view. Instead, it is shown, that continuous scheduling is much better suited to serve VoIP traffic. The paper then proposes a new VoIP-aware resource coordination scheme and shows, through simulation, that the new scheme is scalable and provides good quality for VoIP service in a wide range of network scenarios. The results shown in the paper prove that the new scheme is resilient to increasing hop count, increasing number of simultaneous VoIP sessions and the background traffic load in the network. Compared to other resource coordination schemes the VoIP-aware scheduler significantly increases the number of supported calls.