Special issue on design and programming of signal processors for multimedia communication:Special issue on design and programming of signal processors for multimedia communication

The technical challenges in the design and programming of signal processors for multimedia communication are discussed. The development of terminal equipment to meet such demand presents a significant technical challenge, considering that it is highly desirable that the equipment be cost effective, power efficient, versatile, and extensible for future upgrades. The main challenges in the design and programming of signal processors for multimedia communication are, general-purpose signal processor design, application-specific signal processor design, operating systems and programming support and application programming. The size of FFT is programmable so that it can be used for various OFDM-based communication systems, such as digital audio broadcasting (DAB), digital video broadcasting-terrestrial (DVB-T) and digital video broadcasting-handheld (DVB-H). The clustered architecture design and distributed ping-pong register files in the PAC DSP raise new challenges of code generation.

A programmable architecture for layered multimedia streams in IPv6 networks

A new configurable architecture is presented that offers multiple levels of video playback by accommodating variable levels of network utilization and bandwidth. By utilizing scalable MPEG-4 encoding at the network edge and using specific video delivery protocols, media streaming components are merged to fully optimize video playback for IPv6 networks, thus improving QoS. This is achieved by introducing “programmable network functionality” (PNF) which splits layered video transmission and distributes it evenly over available bandwidth, reducing packet loss and delay caused by out-of-profile DiffServ classes. An FPGA design is given which gives improved performance, e.g. link utilization, end-to-end delay, and that during congestion, improves on-time delivery of video frames by up to 80% when compared to current “static” DiffServ.

A Mobile Multimedia Technology to Aid Those with Alzheimer's Disease

A first-generation, mobile, video-based reminder system offers memory support to those afflicted with mild-stage Alzheimer's disease.

Watermarking for Multimedia Security using Complex Wavelets

This paper investigates the application of complex wavelet transforms to the field of digital data hiding. Complex wavelets offer improved directional selectivity and shift invariance over their discretely sampled counterparts allowing for better adaptation of watermark distortions to the host media. Two methods of deriving visual models for the watermarking system are adapted to the complex wavelet transforms and their performances are compared. To produce improved capacity a spread transform embedding algorithm is devised, this combines the robustness of spread spectrum methods with the high capacity of quantization based methods. Using established information theoretic methods, limits of watermark capacity are derived that demonstrate the superiority of complex wavelets over discretely sampled wavelets. Finally results for the algorithm against commonly used attacks demonstrate its robustness and the improved performance offered by complex wavelet transforms.

Generation and optimization of electron currents along the walls of a conical target for fast ignition

The interaction of an ultraintense laser pulse with a conical target is studied by means of numerical particle-in-cell simulations in the context of fast ignition. The divergence of the fast electron beam generated at the tip of the cone has been shown to be a crucial parameter for the efficient coupling of the ignition laser pulse to the precompressed fusion pellet. In this paper, we demonstrate that a focused hot electron beam is produced at the cone tip, provided that electron currents flowing along the surfaces of the cone sidewalls are efficiently generated. The influence of various interaction parameters over the formation of these wall currents is investigated. It is found that the strength of the electron flows is enhanced for high laser intensities, low density targets, and steep density gradients inside the cone. The hot electron energy distribution obeys a power law for energies of up to a few MeV, with the addition of a high-energy Maxwellian tail.

The Representation of the Female Body in the Multimedia Works of Regina José Galindo

The female body is central to the performance art, poetry and blog site interventions of Guatemalan Regina José Galindo. While Galindo is best known for her performance work, this article compares the hereto overlooked, distinctive and often shocking representations of the female body across her multimedia outputs. We first consider the ways in which, in all three media, Galindo presents an ‘excessive’, carnivalised, grotesque and abject female body. Second, we analyse representations of the female body that has been subjected to violence at a private and public level. In so doing, we show how Galindo not only contests hegemonic visions of gender and (national) identity but also challenges the viewer/reader to engage with, rather than look away from, the violence to which women are subjected in patriarchal society.

Thin catalytic coatings on microreactor walls A way to make industrial processes more efficient

Current trends in the development of microstructured reactors with thin catalytic films (from 100 nm up to several microns) that have self-assembled nanostructures are discussed. A major technique that is used to prepare such films is sol-gel processing. This involves depositing a complex fluid on a microstructured substrate by dip, spin, or spray coating, followed by surfactant removal to form the porous nanostructures. A novel methodology has been developed by which a uniform coating containing controlled amounts of (poly) metallic nanoparticles can be obtained. This elegant strategy is based on the condensation of metal oxide species by self-assembly in the presence of metallic colloids. The potential microreactor applications brought forth by this innovative protocol are placed in perspective in the light of its versatility.