Design and implementation of an offload engine for internet group messaging protocol multicast snooping

As internet protocol (IP) networks in the enterprise space continue to mature, with regards to stability and availability, the desire for these networks to deliver multimedia content will grow. Although IP networks have long had enough bandwidth to support multimedia streams, the deployment of this content seems to have been somewhat limited in the enterprise. The control mechanisms for multicast traffic, both at the IP layer and the data link layer, are still the areas that have not been adopted as widely as their more common unicast counterparts. The authors examine the internet group messaging protocol (IGMP) snooping process that currently runs on enterprise switches and propose an offload hardware engine to accelerate it. Currently, many enterprise switches handle this task with a general-purpose processor within the switch. Although this process adds very little to the overall load of systems currently, as multicast transmissions become more commonplace, the need for this process to be offloaded onto specialised hardware will be a necessity, in order to maintain the stability of the switch and the surrounding network. The proposed hardware model simulations reveal significant increase in the number of packets per second that can be handled compared to software implementations.     

Experimental determination of the absorbed dose to water in a scanned proton beam using a water calorimeter and an ionization chamber

The absorbed dose to water is the reference physical quantity for the energy absorbed in tissue when exposed to beams of ionizing radiation in radiotherapy. The SI unit of absorbed dose to water is the gray (Gy = 1 J/kg). Ionization chambers are used as the dosimeters of choice in the clinical environment because they show a high reproducibility and are easy to use. However, ionization chambers have to be calibrated in order to convert the measured electrical charge into absorbed dose to water. In addition, protocols require these conversion factors to be SI traceable to a primary standard of absorbed dose to water. We present experimental results where the ionization chamber used for the dosimetry for the scanned proton beam facility at PSI is compared with the direct determination of absorbed dose to water from the METAS primary standard water calorimeter. The agreement of 3.2% of the dose values measured by the two techniques are within their respective statistical uncertainties.     

On the use of different types of knowledge in metaheuristics based on constructing solutions

Many metaheuristics are either based on neighborhood search or the construction of solutions. Examples for the latter ones include ant colony optimization and greedy randomized adaptive search procedures. These techniques generally construct solutions probabilistically by sampling a probability distribution over the search space. Solution constructions are generally independent from each other. Recent algorithmic variants include two important features that are inspired by deterministic branch and bound derivatives such as beam search: the use of bounds for evaluating partial solutions, and the parallel and non-independent construction of solutions. In this paper we give a theoretical reason of why these algorithms generally work very well in practice. Second, we confirm our theoretical findings by means of practical examples. After the application to artificial problems, we present experimental results concerning the well-known open shop scheduling problem.     

Bone regeneration with glass ceramic implants and calcium phosphate cements in a rabbit cranial defect model

Hydroxyapatite cement (BoneSource®) and brushite calcium phosphate cement (chronOS? Inject) were tested for fixation of glass ceramic implants (Bioverit®) in experimentally created cranial defects in 24 adult New Zealand White rabbits. Aim of the in vivo study was to assess and compare the biocompatibility and osseointegration of the implanted materials. Macroscopic and histological evaluations were performed 1 month, 3 months, and 6 months postoperatively. All implanted materials were well tolerated by the surrounding tissue. Both bone cements exhibited osteoconductive properties. Differences could be detected regarding to the rates of cement resorption and new bone formation. The brushite cement was resorbed faster than the hydroxyapatite cement. The chronOS? Inject samples exhibited a higher rate of connective tissue formation and an insufficient osseointegration. BoneSource® was replaced by bone with minimal invasion of connective tissue. New bone formation occurred faster compared to the chronOS? Inject group. Bioverit® implants fixed with BoneSource® were successfully osseointegrated.     

Emulsification and mass transfer in ladle metallurgy

Measurements of slag emulsification in gas-stirred ladles were carried out in cold-model systems of different geometric sizes. Detaching of slag droplets – necessary for efficient emulsification – only takes place if the flow velocity at the slag/metal interface exceeds a certain level. The use of a centric nozzle leads at high gas flow rates to considerably larger degrees of emulsification than eccentric stirring. The reason of this phenomenon is that the recirculation flow during centric gas injection transports larger amounts of emulsified droplets into deeper regions of the melt while during eccentric stirring there is more time for reseparation of slag droplets into the top slag. Comparing emulsification results with mass-transfer measurements, the dependence between rate constants as well as degrees of emulsification and Froude number shows similar behaviour.     

REST2: High-performance solar radiation model for cloudless-sky irradiance, illuminance, and photosynthetically active radiation – Validation with a benchmark dataset

REST2, a high-performance model to predict cloudless-sky broadband irradiance, illuminance and photosynthetically active radiation (PAR) from atmospheric data, is presented. Its derivation uses the same two-band scheme as in the previous CPCR2 model, but with numerous improvements. Great attention is devoted to precisely account for the effect of aerosols, in particular.Detailed research-class measurements from Billings, OK are used to assess the performance of the model for the prediction of direct, diffuse and global broadband irradiance. These measurements were made in May 2003 during a sophisticated radiative closure experiment, which involved the best radiometric instrumentation currently available and many ancillary instruments. As a whole, these exceptional measurements constitute the only known modern benchmark dataset made specifically to test the intrinsic performance of radiation models. Using this dataset as reference, it is shown that REST2 performs better than CPCR2 for irradiance, illuminance or PAR predictions. The availability of the turbidity data required by REST2 or other similar models is also discussed, as well as the effect that turbidity has on each component of broadband irradiance, PAR irradiance and illuminance, and on the diffuse/global PAR ratio.     

PLL soft functional failure analysis in advanced logic product using fault based analogue simulation and soft defect localization

Soft defect localization (SDL) is an analysis technique where changes in the pass/fail condition of a test are monitored while a laser is scanned across the device under test (DUT). This technique has proven its usefulness for quickly locating defects that are temperature, frequency, and/or voltage dependant, for example, scan logic soft fault. However, due to high sensibility at analogue circuits SDL meets great challenges. This work gives a new flow to analyze soft functional failure in advanced logic products using fault based analogue simulation and SDL. The paper will present one case study illustrating the application of analogue simulation based soft defect localization flow as an effective means to achieve fault isolation.     

Computer-tailored smoking cessation intervention in a general population setting in Germany: outcome of a randomized controlled trial.

This study reports the outcome of a randomized controlled trial testing a computer-tailored smoking cessation intervention based on the transtheoretical model in a general population setting in Germany. Participants of the smoking intervention study were recruited from an existing general population health examination survey in a university hospital. The sample consisted of 611 current and former smokers at baseline, and of 485 participants in the core group of baseline daily cigarette smokers. Follow-ups were conducted 6, 12, 18, and 24 months after baseline. The intervention was designed for both current and former smokers, involved up to three individualized feedback letters, and was created using expert-system technology. Based on 7-day point-prevalence abstinence and 6-month prolonged abstinence as the outcome measures, the study identified no significant differences between the intervention and control groups. Modeling the full longitudinal data in generalized estimation equation analyses, using different nonresponse procedures, and adjusting for covariates did not alter the results. We conclude that the computer-tailored transtheoretical model-based smoking cessation intervention, as delivered in this study and in this special setting, was ineffective.