Polytechnic University of Milan

About: Polytechnic University of Milan is a education organization based out in Milan, Italy. It is known for research contribution in the topics: Computer science & Finite element method. The organization has 18231 authors who have published 58416 publications receiving 1229711 citations. The organization is also known as: PoliMi & L-NESS.

Asymptotic zero-transition activity encoding for address busses in low-power microprocessor-based systems

Abstract: In microprocessor-based systems, large power savings can be achieved through reduction of the transition activity of the on- and off-chip buses. This is because the total capacitance being switched when a voltage change occurs on a bus line is usually sensibly larger than the capacitive load that must be charged/discharged when internal nodes toggle. In this paper, we propose an encoding scheme which is suitable for reducing the switching activity on the lines of an address bus. The technique relies on the observation that, in a remarkable number of cases, patterns traveling onto address buses are consecutive. Under this condition it may therefore be possible, for the devices located at the receiving end of the bus, to automatically calculate the address to be received at the next clock cycle; consequently, the transmission of the new pattern can be avoided, resulting in an overall switching activity decrease. We present analytical and experimental analyses showing the improved performance of our encoding scheme when compared to both binary and Gray addressing schemes, the latter being widely accepted as the most efficient method for address bus encoding. We also propose power and timing efficient implementations of the encoding and the decoding logic, and we discuss the applicability of the technique to real microprocessor-based designs.

On the Use of Copulas in Hydrology: Theory and Practice

Abstract: The use of copulas in hydrology is quite recent, and many important results still are to be discovered and/or derived. In this work we present some recent advances in hydrological modeling that exploit copulas. These include: (1) the calculation of conditional probabilities and their use in bivariate simulation; (2) the calculation of the level curves of joint distributions; (3) the calculation of the return periods of bivariate events, both in the conditional and unconditional cases; (4) the definition and calculation of the secondary return period; (5) a trivariate model for the temporal structure of the sequence of storms; (6) the statistical calculation of the storm depth; and (7) the calculation of the convolution variance. Several applications to hydrological data are shown. The models presented here may have important implications in many areas of water resources and hydrologic systems.

Global agricultural economic water scarcity

Abstract: Water scarcity raises major concerns on the sustainable future of humanity and the conservation of important ecosystem functions. To meet the increasing food demand without expanding cultivated areas, agriculture will likely need to introduce irrigation in croplands that are currently rain-fed but where enough water would be available for irrigation. “Agricultural economic water scarcity” is, here, defined as lack of irrigation due to limited institutional and economic capacity instead of hydrologic constraints. To date, the location and productivity potential of economically water scarce croplands remain unknown. We develop a monthly agrohydrological analysis to map agricultural regions affected by agricultural economic water scarcity. We find these regions account for up to 25% of the global croplands, mostly across Sub-Saharan Africa, Eastern Europe, and Central Asia. Sustainable irrigation of economically water scarce croplands could feed an additional 840 million people while preventing further aggravation of blue water scarcity.