Architecture of a Memory Manager for an MPEG-2 Video Decoding Circuit

A study of the MPEG-2 video decoding standard in Main Profile @ Main Level has been performed, comparing the different solutions existing for the VLSI implementation of the basic functions (Huffman decoding, IDCT...) included in the standard. Afterwards, a new dynamically configurable architecture is proposed for the memory manager, which is necessary to deal with the large data flow inside the decoder. It is aimed at interfacing the external memory, arbitrating the access requests coming from the different decoding units and allowing generic memory requests through the definition of virtual addresses. It is shown that, by means of a particular data organization, the circuit requires an external memory, which is a 2-MB DRAM in fast page or EDO mode, accessible via a 64-bit bus. The memory manager works at 27 MHz and allows a real-time decoding for MP @ ML bitstreams. It has been synthesized in a 0.8-m two-metal CMOS technology and presents a total area of 5.4 mm2 for 6500 gates.     

Analytic investigation of frequency sensitivity in microwave oscillators: Application to the computation of phase noise in a dielectric resonator oscillator

The conversion of low frequency noise into phase noise in microwave oscillators is studied through an analytical calculation of the pushing factor. This calculation is based on a simplified equivalent circuit for two types of active devices : field effect transistors (Fet) and heterojunction bipolar transistors (hbt). The preeminence in the conversion process of the gate- source capacitance in theFet and the base- emitter junction in thehbt is pointed out. Practical methods are proposed to reduce the phase noise in these circuits.     

Paraxial approximation effect on a dielectric interface analysis

We are presenting a fast new method of analysing a dielectric interface which is assumed to be cylindrically symmetrical. It is based on a multimode Gaussian beam development. Then two different cases are considered and we show the kind of results we can expect from this process. Finally, we explain in detail the relationships between the paraxial approximation and further justified simplifications which lead to an important calculation time decrease.     

Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran and co-workers for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet-stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO₂ production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.     

Provisioning QoS in inter-domain traffic engineering

This work describes an architectural framework that allows inter-domain Traffic Engineering Label Switched Paths (TE-LSPs) with guaranteed quality of service (QoS) to be setup. Such TE-LSPs, called EQ-links, are setup by coordinating path computation elements (PCEs) of neighboring autonomous systems (ASs) along a pre-determined inter-AS path, computed through cooperative interaction between pairs of neighboring ASs. After defining the architectural requirements for the framework, we describe and analyze the Inter-AS Path Computation Protocol (IA-PCP), which computes an interdomain path at the AS level, i.e., selecting a sequence of ASs to the destination, based on a loose source routing approach. The results of the IA-PCP computations are then fed to the PCEs for complete path computation. The proposed architecture has been actually implemented within the testbed of the EuQoS project, which is aimed at enabling end-to-end QoS in the Internet. We report results related to the setup time of EQ-links, measured in the pan-European testbed of the EuQoS project, showing that path computation and setup takes an affordable time overhead.     

Cascaded photonic crystal guides and cavities: spectral studies andtheir impact on integrated optics design

We report on the investigation of cavities coupled to channel waveguides defined in a triangular-lattice photonic crystal etched into a GaAs/AlGaAs heterostructure waveguide. We make use of the internal probe technique by selectively exciting the photoluminescence of InAs dots embedded in the planar waveguide. We collect at the nearby cleaved edge the fundamental mode transmitted through the channel waveguides. From the study of a number of basic cases, we exemplify how one may deduce the main guideline design rules for given cavity-guide interaction mechanisms and then for the implementations of functions such as bending and filtering. In particular, the role of the so-called ministopband (MSB) feature of the waveguide and the nature of the cavity modes involved are outlined     

Fully integrated blue/UV SOI CMOS photosensor for biomedical and environmental applications

In this paper, we present a microsystem for measuring optical power in blue/UV wavelengths (from λ = 200 nm to λ = 450 nm) which includes a photodiode and the analog processing circuit of the photodiode signal, fully integrated in 2 μm SOI CMOS technology. The photodiode has a maximum responsivity for λ = 400 nm. Th photosensor functions as a current to frequency converter. Measurements of the microsystem illuminated by blue and UV LEDs demonstrate the good linear behavior, sensitivity and efficiency of the system.     

Self-Organized Monitoring in Ad-Hoc Networks

We propose in this paper a self-organized monitoring architecture for mobile ad-hoc networks based on a selective scheme where subsets of nodes are managed. These nodes are determined based on their network behavior in order to favor subsets of well-connected nodes. The key idea is to relax the requirements of the management plane, and to use these manageable subsets to monitor the performance of the overall network. We therefore propose a new performance metric to be monitored, in order to estimate the capability of ad-hoc nodes to communicate end-to-end in the network. Extensive simulations show how different parameters affect this metric.