Formal specification of QoS properties

We describe the specification of communication services, with special emphasis being placed on the use of the Temporal Logic of Actions (TLA) to describe the behaviours involved. We show how, startingfrom Message Sequence Charts, this temporal logic may be used to describe The Joint Viewing and Tele Operating Service (JVTOS) and its associated functions; and so lead on to the specification of QoS parameters. We discuss the approach that was taken to determine the exact nature of the Quality of Service parameters, and how the method may be used to extend the specification, and probe further aspects of the services and protocols involved

Prototype performance evaluation of multimedia service components

This paper deals with a formal approach for decomposition and description of multimedia service components and their performance analysis. Our approach is based on the Temporal Logic of Actions (TLA) specifications. A TLA based specification of multimedia components is transformed into process prototypes described with the SPIMS (SICS Protocol Implementation Measurement System) application language. The multimedia component prototype derived in this way is then evaluated with the SPIMS tool for different QoS parameters. The proposed approach using TLA based specifications, transformations in SPIMS application prototypes, and performance analysis provides the background for an computer based system for test specification and performance analysis which is currently under development. We present and discuss practical test scenarios derived from the proposed method for performance analysis of the Audio-Visual Communication (AVC)component of the Joint-Viewing and Tele-Operation Service (JVTOS). The multimedia test scenarios shown use the TCP/IP and XTP protocols on top of FORE ATM networks

Fuel cell drive for urban freight transport in comparison to diesel and battery electric drives: a case study of the food retailing industry in Berlin

The option of decarbonizing urban freight transport using battery electric vehicle (BEV) seems promising. However, there is currently a strong debate whether fuel cell electric vehicle (FCEV) might be the better solution. The question arises as to how a fleet of FCEV influences the operating cost, the greenhouse gas (GHG) emissions and primary energy demand in comparison to BEVs and to Internal Combustion Engine Vehicle (ICEV). To investigate this, we simulate the urban food retailing as a representative share of urban freight transport using a multi-agent transport simulation software. Synthetic routes as well as fleet size and composition are determined by solving a vehicle routing problem. We compute the operating costs using a total cost of ownership analysis and the use phase emissions as well as primary energy demand using the well to wheel approach. While a change to BEV results in 17–23% higher costs compared to ICEV, using FCEVs leads to 22–57% higher costs. Assuming today’s electricity mix, we show a GHG emission reduction of 25% compared to the ICEV base case when using BEV. Current hydrogen production leads to a GHG reduction of 33% when using FCEV which however cannot be scaled to larger fleets. Using current electricity in electrolysis will increase GHG emission by 60% compared to the base case. Assuming 100% renewable electricity for charging and hydrogen production, the reduction from FCEVs rises to 73% and from BEV to 92%. The primary energy requirement for BEV is in all cases lower and for higher compared to the base case. We conclude that while FCEV have a slightly higher GHG savings potential with current hydrogen, BEV are the favored technology for urban freight transport from an economic and ecological point of view, considering the increasing shares of renewable energies in the grid mix.TU Berlin, Open-Access-Mittel - 2022DFG, 398051144, Analyse von Strategien zur vollständigen Dekarbonisierung des urbanen Verkehr

A Case-Control Study of Hantavirus Pulmonary Syndrome during an Outbreak in the Southwestern United States

In May 1993, an outbreak of hantavirus pulmonary syndrome( HPS) occurred in the south-western United States. A case-control study determined risk factors for HPS. Seventeen case-patients were compared with 3 groups of controls: members of case-patient households( household controls), members of neighboring households( near controls), and members of randomly selected households ≥ 24 km away ( far controls). Investigators trapped more small rodents at case households than at near ( P = .03) or far control households( P = .02). After the number of small rodents was controlled for,case-patients were more likely than household controls to hand plow (odds ratio [OR], 12.3; 95% confidence interval [ CI], 1.1-143.0) or to clean feed storage areas (OR, 33.4; 95% CI, 1.7-666.0). Case-patients were more likely than near controls to plant( OR, 6.2; 95% CI, 1.1-34.0) and more likely than far controls to clean animal sheds( OR, 11.9;95% CI, 1.4-103.0). Peridomestic cleaning, agricultural activities, and an increased number of small rodents at the household were associated with HPS