Speculation in elastic systems

Speculation is a well-known technique for increasing parallelism of the microprocessor pipelines and hence their performance. While implementing speculation in modern design practice is error-prone and mostly ad-hoc, this paper proposes a correct-by-construction method for implementing speculation in Elastic Systems. The technique is based on applying provably correct transformations such as early evaluation, insertion of anti-tokens and bubbles, retiming, and sharing. It allows to explore different micro-architectural solutions for better design trade-offs. The benefits of speculation are illustrated with two examples in which these transformations are systematically applied. The method proposed in this paper is amenable for automation in a synthesis flow.Postprint (published version

The Forward Exchange Market, Speculation, and Exchange Market Intervention

This paper develops a stochastic equilibrium model of an open economy incorporating speculation in the forward exchange market. The model is used to examine two issues. The first is the role of speculation in stabilizing the economy against stochastic disturbances. Much risk averse speculation stabilizes domestic income against disturbances in the domestic bond market and forward exchange marketbut exacerbates the effect of foreign disturbances. Speculation may dampen or augment the effect of money market and output supply disturbances depending upon the share of foreign bonds in total wealthand the interest elasticity of bond demand. The second issue that the model addresses is the role of the forward market in stabilization policy. Forward market intervention (or its equivalent in this model,sterilized spot market intervention) does not provide monetary authorities additional leverage in stabilizing income beyond unsterilized spot market intervention. Intervention rules based on reactions to both the forward and the spot exchange rates, however, can outper-form intervention policies responding to the spot rate alone,regardless of the market in which intervention occurs.

Price Volatility and Banking in Green Certificate Markets

There is concern that prices in a market for Green Certificates (GCs) primarily based on volatile wind power will fluctuate excessively, leading to corresponding volatility of electricity prices. Applying a rational expectations simulation model of competitive storage and speculation of GCs the paper shows that the introduction of banking of GCs may reduce price volatility considerably and lead to increased social surplus. Banking lowers average prices and is therefore not necessarily to the benefit of “green producers”. Proposed price bounds on GC-prices will reduce the importance of banking and even of the GC system itself.electricity; environment; commodity speculation; green certificates; marketable permits; uncertainty

Price Volatility and Banking in Green Certificate Markets

There is concern that prices in a market for Green Certificates (GCs) primarily based on volatile wind power will fluctuate excessively, leading to corresponding volatility of electricity prices. Applying a rational expectations simulation model of competitive storage and speculation of GCs the paper shows that the introduction of banking of GCs may reduce price volatility considerably and lead to increased social surplus. Banking lowers average prices and is therefore not necessarily to the benefit of “green producers”. Proposed price bounds on GC -prices will reduce the importance of banking and even of the GC system itself.Electricity; Green Certificates; Uncertainty; Commodity Speculation

Observation of Umklapp processes in non-crystalline materials

Umklapp processes are known to exist in cristalline materials, where they control important properties such as thermal conductivity, heat capacity and electrical conductivity. In this work we report the provocative observation of Umklapp processes in a non-periodical system, namely liquid Lithium. The lack of a well defined periodicity seems then not to prevent the existence of these scattering processes mechanisms provided that the local order of the systems i.e. the maxima of the static structure factor supply the equivalent of a reciprocal lattice vector in the case of cristalline materials.Comment: 13 pages P

Neutron scattering studies of Zn-doped La2-xSrxCuO4

This paper reviews studies of the spatial modulation of spin in La2-xSrxCuO4 (LSCO) through neutron-scattering measurements of the elastic magnetic peaks, with emphasis on Zn-doped LSCO. The elastic incommensurate magnetic peaks can be categorized in two classes with respect to the temperature dependence. Nd-doped LSCO, La2CuO4+y and LSCO with x ~ 1/8 exhibit an ordinary power law behavior. On the other hand, Zn-doped LSCO and LSCO with x = 0.02-0.07 show an exponential temperature dependence, and the correlation lengths stay short. This discrepancy can be attributed to the difference in the mechanism of pinning spin fluctuations. The former systems have pinning centers which is coherent to the lattice. In the latter, however, pinning centers are randomly scattered in the CuO2 planes, thus incoherent. The incoherent pinning model is discussed with referring to recent mu-SR studies.Comment: 6 pages, including 4 figures and 1 table. Proceedings for ISS2000 (Tokyo, October 2000