Elasticity and Petri nets

Digital electronic systems typically use synchronous clocks and primarily assume fixed duration of their operations to simplify the design process. Time elastic systems can be constructed either by replacing the clock with communication handshakes (asynchronous version) or by augmenting the clock with a synchronous version of a handshake (synchronous version). Time elastic systems can tolerate static and dynamic changes in delays (asynchronous case) or latencies (synchronous case) of operations that can be used for modularity, ease of reuse and better power-delay trade-off. This paper describes methods for the modeling, performance analysis and optimization of elastic systems using Marked Graphs and their extensions capable of describing behavior with early evaluation. The paper uses synchronous elastic systems (aka latency-tolerant systems) for illustrating the use of Petri nets, however, most of the methods can be applied without changes (except changing the delay model associated with events of the system) to asynchronous elastic systems.Peer ReviewedPostprint (author's final draft

REFERENCES

and „ � and the technology parameters. For all cases, we observe that the total latency is not significantly higher than the minimum source-sink delay of 2739 ps (from Table I). VI. CONCLUSION Automated buffered routing is a necessity in modern very large-scale integration design. The contributions of this paper are two new problem formulations for buffered routing for single- and multiple-clock domains. Both of these formulations address problems that will become more prominent in future designs. Any computer-aided design (CAD) tools currently performing buffer insertion will eventually have to deal with synchronizer insertion. Furthermore, any SoC routing CAD tools will have to handle routing across multiple clock domains due to the increasing use of IPs. We solve both problems optimally in polynomial time via the RBP and GALS algorithms that build upon the fast path algorithm of [17]. Experimental results validate the correctness and practicality of the two algorithms for an aggressive technology. ACKNOWLEDGMENT The authors would like to thank H. Zhou for supplying fast path code and also to M. Thiagarajan for help with the figures and researching the background material on the MCFIFOs

Effective product recommendation using the real-time web

Paper presented at the Thirtieth SGAI International Conference on Artificial Intelligence (AI-2010), 14-16 December 2010, Cambridge, England, UKThe so-called real-time web (RTW) is a web of opinions, comments, and personal viewpoints, often expressed in the form of short, 140-character text messages providing abbreviated and highly personalized commentary in real-time. Today, Twitter is undoubtedly the king of the RTW. It boasts 190 million users and generates in the region of 65m tweets per day. This RTW data is far from the structured data (movie ratings, product features, etc.) that is familiar to recommender systems research but it is useful to consider its applicability to recommendation scenarios. In this paper we consider harnessing the real-time opinions of users, expressed through the Twitter-like short textual reviews available on the Blippr service (www.blippr.com). In particular we describe how users and products can be represented from the terms used in their associated reviews and describe experiments to highlight the recommendation potential of this RTW data-source and approach.Science Foundation IrelandEmbargo until January 2012 - AV 8/2/201

Multidecadal variability of summer temperature over Romania and its relation with Atlantic Multidecadal Oscillation

We investigate the multidecadal variability of summer temperature over Romania as measured at 14 meteorological stations with long term observational records. The dominant pattern of summer temperature variability has a monopolar structure and shows pronounced multidecadal variations. A correlation analysis reveals that these multidecadal variations are related with multidecadal variations in the frequency of four daily atmospheric circulation patterns from the North Atlantic region. It is found that, on multidecadal time scales, negative summer mean temperature (TT) anomalies are associated with positive sea level pressure (SLP) anomalies centered over the northern part of the Atlantic Ocean and Scandinavia and negative SLP anomalies centered over the northern part of Africa. It is speculated that a possible cause of multidecadal fluctuations in the frequency of these four patterns are the sea surface temperature anomalies associated to the Atlantic Multidecadal Oscillation. These results have implications for predicting the evolution of summer temperature over Romania on multidecadal time scales