An FPGA-Based Video Compressor for H.263 Compatible Bit Streams

This paper presents an FPGA architecture for video encoding according to the H.263 standard for video teleconferencing systems. The implementation is based on an off-the-shelf FPGA1 and is embedded in a PCI plug-in card2 with on-board SRAM plus external SRAM. The most complex part of the H.263 protocol, a base-line encoder, was implemented. The strategies, which have been applied to build the complex encoding operations, are treated in this paper. The complete application is able to operate at 30 MHz. This leads to a maximum compression speed of 120 Mbit/s allowing simultaneous real-time operation of several video streams in a single reconfigurable chip. Enhanced coding options can also become implemented with present-day FPGAs. The use of FPGA technology enables the adaptation of hardware to various protocols and environments by software and therefore saves development time and hardware costs

Efficacy of platelet-rich fibrin on bone formation, part 1: Alveolar ridge preservation.

PURPOSE To investigate the use of platelet-rich fibrin for alveolar ridge preservation compared to natural healing, bone graft material and platelet-rich fibrin in combination with bone graft material. MATERIALS AND METHODS The present systematic review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The review examined randomised controlled trials comparing the clinical outcomes of platelet-rich fibrin with those of other modalities for alveolar ridge preservation. Studies of third molar extraction site healing were excluded. The studies were classified into three categories: natural wound healing vs platelet-rich fibrin; bone graft material vs platelet-rich fibrin; and bone graft material vs bone graft material and platelet-rich fibrin. RESULTS From 179 articles identified, 16 randomised controlled trials were included. Owing to the heterogeneity of the investigated parameters, it was not possible to perform a meta-analysis. In total, 10 randomised controlled trials compared platelet-rich fibrin to natural wound healing, with seven of these demonstrating favourable outcomes to either limit postextraction dimensional changes or improve new bone formation in the platelet-rich fibrin group. Three of four studies comparing healing with bone graft material to platelet-rich fibrin found that the latter led to significantly greater horizontal or vertical bone resorption, and the bone graft material was more able to maintain the ridge dimensions. Two out of three randomised controlled trials investigating healing with both bone graft material and platelet-rich fibrin reported better outcomes using this combined approach than with bone graft material alone. All studies investigating soft tissue healing with platelet-rich fibrin demonstrated better outcomes in the platelet-rich fibrin group. CONCLUSIONS The majority of studies comparing healing with platelet-rich fibrin to natural healing concluded that the former more successfully limits postextraction dimensional changes than the latter. However, 75% of studies investigating platelet-rich fibrin vs bone graft material reported better results in the bone graft group with respect to its ability to maintain postextraction dimensional changes. The addition of platelet-rich fibrin to bone graft material may improve clinical outcomes, although data are limited

Efficacy of platelet-rich fibrin on bone formation, part 2: Guided bone regeneration, sinus elevation and implant therapy.

PURPOSE To investigate the effect of platelet-rich fibrin on bone formation by investigating its use in guided bone regeneration, sinus elevation and implant therapy. MATERIALS AND METHODS This systematic review and meta-analysis were conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The eligibility criteria comprised human controlled clinical trials comparing the clinical outcomes of platelet-rich fibrin with those of other treatment modalities. The outcomes measured included percentage of new bone formation, percentage of residual bone graft, implant survival rate, change in bone dimension (horizontal and vertical), and implant stability quotient values. RESULTS From 320 articles identified, 18 studies were included. Owing to the heterogeneity of the investigated parameters, a meta-analysis was only possible for sinus elevation. There is a general lack of data from comparative randomised clinical trials evaluating platelet-rich fibrin for guided bone regeneration procedures (only two studies), with no quantifiable advantages in terms of new bone formation or dimensional bone gain found in the platelet-rich fibrin group. For sinus elevation, the meta-analysis demonstrated no advantage in terms of histological new bone formation in the control group (bone graft alone) compared with the test group (bone graft and platelet-rich fibrin). Two studies demonstrated that platelet-rich fibrin may shorten healing periods prior to implant placement. Platelet-rich fibrin was also shown to slightly enhance primary implant stability (implant stability quotient value < 5) as assessed using implant stability quotients and resonance frequency analysis parameters, with no histological data evaluating bone-implant contact yet available on this topic. In one study, platelet-rich fibrin was shown to improve the clinical parameters when utilised as an adjunct for the treatment of peri-implantitis. CONCLUSIONS In the majority of studies, platelet-rich fibrin offered little or no clear advantage in terms of new bone formation as evaluated in various studies on guided bone regeneration and sinus elevation, nor in implant stability and treatment of peri-implantitis. Various authors and systematic reviews on the topic have now expressed criticism of the various study designs and protocols, and the lack of appropriate controls and available information regarding patient selection. Well-controlled human studies on these specific topics are required

A practical approach for photometric acquisition of hair color

In this work a practical approach to photometric acquisition of hair color is presented. Based on a single input photograph of a simple setup we are able to extract physically plausible optical properties of hair and to render virtual hair closely matching the original. Our approach does not require any costly special hardware but a standard consumer camera only.Arno Zinke, Tomás Lay, Anton Andriyenk

A Hybrid Approach for the ATLAS Level-2 Trigger

There are several different concepts for the ATLAS Level-2 trigger under investigation, all of which have to cope with the following challenges The high luminosity trigger has to cope with an event frequency of 100 kHz. One result of the Level-2 demonstrator program was that such an event frequency is a serious problem for present farm solutions. For the low luminosity trigger the critical item is the processing of the complete data volume of the Transition-Radiation-Tracker (TRT). This leads to an enormous demand in terms of computing power and bandwidth. These above problems could be resolved by a hybrid trigger combining an FPGA-processor and a processor-farm. The inserted FPGA-processor layer executes simple reconstruction algorithms and applies loose physics selection criteria. These criteria already reject 80% of the events with a high - pt trigger and reduce the bandwith by a factor of 6 in regard to the full scan TRT. This would scale down the farm and strongly reduce the networking requirements. The FPGA-processor layer and the farm together build a cost e ective hybrid solution for the level-2 trigger