Multimedia transport service and protocol issues

This paper considers the issues of a real time transport service needed by multimedia applications for transferring digital video and audio. Three classes of transport service are defined with different levels of real time constraints. Methods for error control are considered for the classes, and the classes are discussed with respect to the application requirements

Greenhouse gas performance of biodiesel production from straw: Soil carbon changes and time-dependent climate impact

Background: Use of bio‑based diesel is increasing in Europe. It is currently produced from oilseed crops, but can also be generated from lignocellulosic biomass such as straw. However, removing straw affects soil organic carbon (SOC), with potential consequences for the climate impact of the biofuel. This study assessed the climate impacts and energy balance of biodiesel production from straw using oleaginous yeast, with subsequent biogas production from the residues, with particular emphasis on SOC changes over time. It also explored the impact of four different scenarios for returning the lignin fraction of the biomass to soil to mitigate SOC changes. Climate impact was assessed using two methods, global warming potential (GWP) and a time‑dependent temperature model (∆Ts) that describes changes in mean global surface temperature as a function of time or absolute temperature change potential (AGTP). Results: Straw‑derived biodiesel reduced GWP by 33–80% compared with fossil fuels and primary fossil energy use for biodiesel production was 0.33–0.80 MJprim/MJ, depending on the scenario studied. Simulations using the time‑dependent temperature model showed that a scenario where all straw fractions were converted to energy carriers and no lignin was returned to soil resulted in the highest avoided climate impact. The SOC changes due to straw removal had a large impact on the results, both when using GWP and the time‑dependent temperature model. Conclusions: In a climate perspective, it is preferable to combust straw lignin to produce electricity rather than returning it to the soil if the excess electricity replaces natural gas electricity, according to results from both GWP and time‑dependent temperature modelling. Using different methods to assess climate impact did not change the ranking between the scenarios, but the time‑dependent temperature model provided information about system behaviour over time that can be important for evaluation of biofuel systems, particularly in relation to climate target deadlines

Breast Cancer, Sickness Absence, Income and Marital Status. A Study on Life Situation 1 Year Prior Diagnosis Compared to 3 and 5 Years after Diagnosis

Background: Improved cancer survival poses important questions about future life conditions of the survivor. We examined the possible influence of a breast cancer diagnosis on subsequent working and marital status, sickness absence and income. Materials: We conducted a matched cohort study including 4,761 women 40–59 years of age and registered with primary breast cancer in a Swedish population-based clinical register during 1993–2003, and 2,3805 women without breast cancer. Information on socioeconomic standing was obtained from a social database 1 year prior and 3 and 5 years following the diagnosis. In Conditional Poisson Regression models, risk ratios (RRs) and 95 % confidence intervals (CIs) were estimated to assess the impact of a breast cancer diagnosis. Findings: Three years after diagnosis, women who had had breast cancer more often had received sickness benefits (RR = 1.49, 95 % CI 1.40–1.58) or disability pension (RR = 1.47, 95 % CI 1.37–1.58) than had women without breast cancer. W

Multimedia transport service and protocol issues

This paper considers the issues of a real time transport service needed by multimedia applications for transferring digital video and audio. Three classes of transport service are defined with different levels of real time constraints. Methods for error control are considered for the classes, and the classes are discussed with respect to the application requirements.Also appearing in the Proceedings of the 3rd MultiG Workshop, KTH, Stockholm, Sweden.</p

Towards predictable ILP performance-controlling communication buffer cache effects

Cache memory behavior is becoming more and more important as the speed of CPUs is increasing faster than the speed of memories. The operation of caches are statistical which means that the system level performance becomes unpredictable. In this paper we investigate the worst case behavior of cache line conflicts in the context of communication protocols implemented using Integrated Layer Processing. The goal of our work is to control the cache by placing communication buffers and code in non-conflicting positions in the cache. The result would be higher and more predictable performance. Our first results indicate that the worst case behavior can be up to almost four times slower than the best case

Towards predictable ILP performance-controlling communication buffer cache effects

Cache memory behavior is becoming more and more important as the speed of CPUs is increasing faster than the speed of memories. The operation of caches are statistical which means that the system level performance becomes unpredictable. In this paper we investigate the worst case behavior of cache line conflicts in the context of communication protocols implemented using Integrated Layer Processing. The goal of our work is to control the cache by placing communication buffers and code in non-conflicting positions in the cache. The result would be higher and more predictable performance. Our first results indicate that the worst case behavior can be up to almost four times slower than the best case

The applicability of integrated layer processing

In this paper we review previous work on the applicability and performance of Integrated Layer Processing (ILP). ILP has been shown to clearly improve computer communication performance when integrating simple data manipulation functions, but the situation has been less clear for more complex functions and complete systems. We discuss complications when applying ILP to protocol stacks, the requirements of ILP on the communication subsystem, caching aspects, the importance of the processor registers, and a model for predicting the performance of data manipulation functions. We conclude that the main drawback of ILP is its limited aplicability to complex data manipulation functions. The performance to expect from an ILP implementation also depends heavily on the protocol architecture and the host system architecture