Communication costs

Hospital stay reduced community costs increased. Overall costs similar Hospital stay reduced. 

Commission of the European Communities. COST Project 68. Sewage Sludge Processing. Final Report of the Management Committee. 1975. 

In this paper, we propose a dynamic SDR scheme to reduce both the key storage cost and the rekey communication cost of static SDR. Dynamic SDR uses a key tree that is large enough to hold currently active members (as opposed to all members, both active and inactive) in order to reduce key storage. This... 

The performance metrics of interest are the key storage cost (both at the member side and at the GCKS side) and rekey communication cost. We repeat each simulation with different seed five times and take the average. The key storage cost is measured as the key storage described in the previous section. More specifically, we assume to use 3DES for encryption and each label has 128-bits of storage. 

The rekey communication cost is measured as the number of unit-size rekey messages (assuming one message contains one 128-bit key) per unit time, which is further divided into multicast cost and unicast cost. 

In summary, the overall rekey communication cost of static SDR is... 

Figure 9 Rekey communication cost of static SDR and dynamic SDR for different group size...

Figure 10(a) shows the communication cost, C(i, of dynamic SDR with probabilistic shifting for the five different configurations. We observe that, without shifting (p = 0), the rekey communication cost tends to be higher when members lifetime is of high variance. 

Figure 10 Rekey communication cost of dynamic SDR combined shifting on configurations with E[M] = 1000...

Fig. 10(b) shows the evaluation of threshold-based shifting scheme applied to the five configurations in Table 1. In the figure, it appears that, all configurations have a local minimum rekey communication cost when T 0.9. When T goes beyond 0.9, there is a dramatically increase of the rekey cost. This is... 

Rekey communication cost Rekey communication cost Rekey communication cost Rekey communication cost Rekey communication cost... 

A performance comparison between static SDR and LKH is given in [3], Both the key storage and the rekey communication cost are compared in different scenarios, e g. immediate rekeying, periodical batch rekeying and membership batch rekeying. It was shown that static SDR outperforms LKH in batch rekeying while LKH outperforms static SDR in immediate rekeying. 

The authors are indebted to H.-D. Meyer for support with the MCTDH calculations and to M. Doscher for performing the computations for Fig. 2. This work has been supported financially by the Deutsche Forschungsgemeinschaft (H. K.), by the Hungarian Research Foundation (OTKA) Grant No. T032980 (P. G. S.) and by the European Community, COST Action D26. 

Once a program has been implemented, measurement-based evaluation is useful to refine its implementation by highlighting sources of inefficiency like load imbalance or high communication costs. Performance visualization, based on recorded program behavior, is a particularly powerful method for detecting unexpected behavior within a parallel program. 

Atom decomposition methods are the most straightforward to implement, reflected by their usage in major simulation packages such as CHARMM and GROMOS. Yet their dependence on global communications limits the number of processors that can be effectively used. In the LJ benchmark, communication costs begin to dominate by the time hundreds of processors have been used, since there is little speed-up when the number of processors is doubled. 

Force decomposition algorithms based on a block decomposition of the force matrix reduce the memory and communication costs by a factor of /P versus the atom decomposition algorithms. In the LJ benchmark, the force decomposition algorithm continued to speed up, even when hundreds of processors were used. 

The objectives of the Community COST 64b project and the contribution it has made in this field is described. A list of 129 substances which might be included in List I of the dangerous substances directive is annexed. 

If s my pleasure to weleome you, on behalf of the Belgian Government, on this first joint workshop of the eoneerted actions of the European Communities COST 641 Organic Micropollutants in the Aquatic Environmenf and COST 681 Treatment and Use of Organic Sludge and Liquid Agricultural Wastes . 

This work was partially supported by Technology Development Centre of Finland (TEKES) and the Commission of European Communities (COST-503 project)... 

The authors gratefully acknowledge the financial support of the Commission of European Communities, COST PECO 12382 and the support of the Hungarian OTKA Foundation under No. 6 and 1/3/2239, they are grateful to Gedeon Richter Co. for supplying vinpocetin. 

Reduced communication costs by obviating the need for costly network connections among remote computers and time-consuming data transmission across a network. 

On today s parallel computers communication is very slow compared to floating-point performance. It is sometimes possible to use multiple random number sequences to reduce the communication costs in a Monte Carlo simulation. An example occurs in our parallel-path integral calculations... 

The purpose and type of analysis undertaken will determine the categories for which cost data will need to be collected. For example, hospital costs may involve identifying costs of services, facihties and overheads, while community costs may involve costs associated with visits to GPs, nurses or other health professionals. From a third party perspective one may want to consider actual charges rather than costs because often third parties do not cover total health care costs. As regards patients it is important to place a value both on their time and that of their family, as well as to take into account any out-of-pocket expenses incurred. In such matters, however, it can be important to assess the relative importance of a cost item to the overall outcome since the cost of including some minor costs may not be justified by their significance in the total picture. 

MP. Pedeferri, P. Pedeferri, Stainless Steel in Concrete , Annual Progress Report, European Community, COST 521 Workshop,... 

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