A multimedia interactive conferencing application for personalworkstations

The multimedia interactive conferencing application (MICA), a personal-workstation application for multipoint visual teleconferencing, is described. MICA allows people at two or more locations to share visual material such as documents, photographs, and computer screens in a highly interactive way. It supports the distribution, storage, retrieval, and high-quality display of visuals, real-time interaction by pointing and annotation, and meeting services facilities. The context of multimedia teleconferencing and computer-supported cooperative work is established, relating earlier research to the design of MICA. The services MICA offers are outlined. The handling, compression, and display of multiple media, and the design of a suitable user interface for MICA are discussed     

Design aspects of MOS-controlled thyristor elements: technology,simulation, and experimental results

2.5-kV thyristor devices have been fabricated with integrated MOS controlled n⁺-emitter shorts and a bipolar turn-on gate using a p-channel DMOS technology. Square-cell geometries with pitch variations ranging from 15 to 30 μm were implemented in one- and two-dimensional arrays with up to 20000 units. The impact of the cell pitch on the turn-off performance and the on-state voltage was studied for arrays with constant cathode area as well as for single-cell structures. By realizing MOS components with submicrometer channel lengths, scaled single cells are shown to turn off with current densities of several kiloamperes per square centimeter at a gate bias of 5 V. In the case of multi-cell ensembles, turn-off performance is limited due to inhomogeneous current distribution. Critical process parameters as well as the device behavior were optimized through multidimensional numerical simulation     

Controlled ventilation during NMR spectroscopic studies: hemodynamic and biochemical consequences

The effects of different ventilation methods on cardiac output measured by the indicator-dilution method, liver blood flow measured by a deuterium washout technique using 2H nuclear magnetic resonance (NMR) and liver concentrations of ATP and intracellular pH determined with 31P NMR were compared in anesthetized rats. No differences in mean arterial blood pressure were demonstrable with the different modes of ventilation. However, significant drops in cardiac output were observed between freely breathing and animals ventilated with positive pressure but not the high frequency oscillatory method (407 +/- 46 and 520 +/- 88 vs. 633 +/- 86 ml/min/kg, p less than 0.05 and p = NS, respectively). Moreover, liver blood flow was significantly reduced during positive pressure but not high frequency oscillatory ventilation compared with free breathing rats (32 +/- 4 and 43 +/- 10 vs. 46 +/- 8 ml/100 g, p less than 0.05 and p = NS, respectively). 31P NMR spectroscopy revealed no effects of either ventilation method on tissue ATP or intracellular pH as estimated by the chemical shift of inorganic phosphate. These data suggest that controlled ventilation in normal rats accomplished with standard positive pressure methods is associated with major decreases in cardiac output and liver blood flow despite maintenance of normal blood pressure. High frequency oscillatory ventilation appears to effect less compromise of cardiac output and hepatic perfusion than positive pressure ventilation and may, therefore, be preferable for some biological studies.     

Extending the power line LAN up to the neighborhood transformer

This article reports on the performance of audio, video, multimedia, and other high-data-rate in-home networking applications. The article starts by describing the problems encountered in power line communication channels in terms of frequency response and noise characteristics, and explains how in-home power line LANs can be extended to the neighborhood transformer. OFDM physical layers providing speeds of 45 Mb/s and 200 Mb/s as well as QoS and security are introduced. Finally, the results of large tests involving several thousands of nodes are described.     

High-power 980 nm quantum dot broad area lasers

High-power quantum dot broad area lasers emitting at 980 nm are presented. Continuous-wave output powers of 4.3 W from a 50 /spl mu/m stripe width laser and of 6.3 W from a 100 /spl mu/m stripe width laser were achieved at 15/spl deg/C     

Obtaining Characteristic 4f–4f Luminescence from Rare Earth Organic Chelates

We report a study of a series of heavy rare earth tris‐8‐hydroxyquinolines (REQ₃s), using UV‐visible absorption spectroscopy, infrared absorption spectroscopy, and photoluminescence (PL) measurements. We show that the heavy REQ₃s are all chemically similar to each other and to aluminium tris‐8‐hydroxyquinoline, at least in terms of the ligand behavior. Characteristic rare earth 4f–4f luminescence is only observed for ErQ₃ and YbQ₃ due to the relatively low energy of the ligand triplet state. We show that a triplet transfer mechanism cannot be responsible for the observed Yb 4f–4f luminescence observed in YbQ₃. Instead, an internal chemiluminescent process is shown to be energetically favorable. The thin film PL spectra of all the heavy REQ₃s are dominated by triplet emission, except for that of ErQ₃, for which transfer to the Er³⁺ ion represents an efficient alternative. The PL spectra of powder samples, which would be expected to consist of approximately equal amounts of both isomers, are dominated by singlet emission. This is in contrast to the results from the thin films, and suggests that the isomer which predominates in the thin films has a much higher intersystem crossing rate than the other isomer.     

The origination and optimization of Si/SiO/sub 2/ interface roughness and its effect on CMOS performance

As CMOS device dimensions scale down to 100 nm and beyond, the interface roughness between Si and SiO/sub 2/ has become critical to device performance and reliability. Si/SiO/sub 2/ interface roughness degrades channel mobility decreasing drive currents. The authors have used atomic force microscopy to study surface roughness in the processing of 0.16 /spl mu/m CMOS integrated circuits. All of the process steps that could potentially affect the interface roughness have been studied. The results show that oxidation is the major contributor to the interface roughness. The rms roughness is found to be linearly dependent on oxide thickness. Transistors with Si/SiO/sub 2/ interface rms roughness that has been reduced from 1.6 to 1.1 /spl Aring/ by reducing oxide thicknesses show improved device drive currents. This technique for interfacial smoothing and device performance improvement has the advantage of being easily implemented in today's technology.     

Improved Poisson intensity estimation: denoising application using Poisson data

Recently, Timmermann and Nowak developed algorithms for estimating the means of independent Poisson random variables. The algorithms are based on a multiscale model where certain random variables are assumed to obey a beta-mixture density function. Timmermann and Nowak simplify the density estimation problem by assuming the beta parameters are known and only one mixture parameter is unknown. They use the observed data and the method of moments to estimate the unknown mixture parameter. Taking a different approach, we generate training data from the observed data and compute maximum likelihood estimates of all of the beta-mixture parameters. To assess the improved performance obtained by the proposed modification, we consider a denoising application using Poisson data.     

MPEG-21: The 21st century multimedia framework

The lack of interoperable (and thus standardized) solutions is stalling the deployment of advanced multimedia packaging and distribution applications although most of the individual technologies are indeed already present. This motivated MPEG (ISO/IEC JTCl SC29 WGI I) in June 2000 to start working on the definition of enabling normative technology for the multimedia applications of the 21st century: MPEG-21 "Multimedia Framework." MPEG-21's approach is to define a framework to support transactions that are interoperable and highly automated, specifically taking into account digital rights management (DRM) requirements and targeting multimedia access and delivery using heterogeneous networks and terminals. This article first outlines the context and background of the MPEG-21 initiative. Then, an overview of MPEG-21 technology is given. Subsequently, it is discussed how MPEG-21 can provide solutions for universal multimedia access (UMA). UMA is also one of the use cases that has led to the creation of a new part in MPEG-21 dealing with digital item adaptation. Finally, this article concludes with an overview of MPEG-21 related activities and an outlook on future developments.     

An investigation of bulk recycling planning for an electronics recycling facility receiving industrial returns versus residential returns

Since most end-of-life electronics equipment contain hazardous materials such as lead solder alloys or lead-impregnated glass, it is important to divert them from landfills. For end-of-life products that are not repairable and do not contain reusable parts, bulk recycling is an alternative to recover base materials. In this paper, we contrast production and recycling planning and distribution decisions, activities, and costs. We reveal that while a traditional production facility connects suppliers and customers, a recycling facility connects both "input" and "output" customers. As a result, decisions in short-term bulk recycling planning include what products to accept, what products to process and reprocess, and what products to carry in inventory. Many recyclers set prices to receive "input" based on experience. For various prices to receive "input", we use a new analytical model to investigate the sensitivity of the short-term bulk recycling planning decisions in products from two different sources: industrial returns versus residential returns. The results of the case study show that different decisions are recommended for the industrial returns versus the residential returns when the total quantity of the incoming products is equal.