Integrity static analysis of COTS/SOUP

This paper describes the integrity static analysis approach developed to support the justification of commercial off-the-shelf software (COTS) used in a safety-related system. The static analysis was part of an overall software qualification programme, which also included the work reported in our paper presented at Safecomp 2002. Integrity static analysis focuses on unsafe language constructs and “covert” flows, where one thread can affect the data or control flow of another thread. The analysis addressed two main aspects: the internal integrity of the code (especially for the more critical functions), and the intra-component integrity, checking for covert channels. The analysis process was supported by an aggregation of tools, combined and engineered to support the checks done and to scale as necessary. Integrity static analysis is feasible for industrial scale software, did not require unreasonable resources and we provide data that illustrates its contribution to the software qualification programme

Stochastic Differential Equations Driven by Fractional Brownian Motion and Standard Brownian Motion

We prove an existence and uniqueness theorem for solutions of multidimensional, time dependent, stochastic differential equations driven simultaneously by a multidimensional fractional Brownian motion with Hurst parameter H>1/2 and a multidimensional standard Brownian motion. The proof relies on some a priori estimates, which are obtained using the methods of fractional integration, and the classical Ito stochastic calculus. The existence result is based on the Yamada-Watanabe theorem.Comment: 21 page

Producing more rice with less water from irrigated systems

Irrigation management / Water use efficiency / Crop production / Water requirements / Water balance / Rice / Water distribution / Irrigated farming / Productivity / On-farm research / Irrigation scheduling / Groundwater / Conjunctive use / Rehabilitation / Modernization / Farmer participation / Farming systems / Irrigation systems / Crop-based irrigation / Asia / Philippines / Sri Lanka / Bangladesh / China / Malaysia / USA

Linking farm management and ecosystem service provision: Challenges and opportunities for soil erosion prevention in Mediterranean silvo-pastoral systems

At both local and landscape levels, farm management is the main driver of land cover change influencing ecosystem functions, processes and traits. In Mediterranean large-scale silvo-pastoral systems these changes can have serious implications in the provision of valuable ecosystem services (ES). Current ES assessment, mapping and valuation are still focused in representing the state and trends of ES provision, often missing the link to actual farm management and farm management systems. We propose an approach that, at the farm level, combines the classification of farm management systems with indicators of ES provision. This is illustrated for soil erosion prevention, a key ES in mitigating current and future impacts in Mediterranean regions and the proposed approach is tested in Southern Portugal. We characterize thirty-eight large-scale farm management units (FMU) regarding their management system and environmental traits. Each FMU was then classified according to their management system and a set of ES indicators was calculated. To classify the FMU, data on livestock composition and grazing density, pastures, and soil mobilization practices were object of a cluster analysis and the result was tested against a set of ES indicators. The results highlight the implications and challenges for the provision of soil erosion prevention under different farm management systems and draw a clear relation between more intensive management practices and the degradation of service provision. Our results can also be used to support land management and policy design through the definition of intensity thresholds that consider the local environmental and ecological condition

Structural Properties of the Disordered Spherical and other Mean Field Spin Models

We extend the approach of Aizenman, Sims and Starr for the SK-type models to their spherical versions. Such an extension has already been performed for diluted spin glasses. The factorization property of the optimal structures found by Guerra for the SK model, which holds for diluted models as well, is verified also in the case of spherical systems, with the due modifications. Hence we show that there are some common structural features in various mean field spin models. These similarities seem to be quite paradigmatic, and we summarize the various techniques typically used to prove the structural analogies and to tackle the computation of the free energy per spin in the thermodynamic limit.Comment: 24 page

Some structural and emergent trends in Social Housing in Portugal. Rethinking housing policies in times of crisis

First of all, this article intends to analyse some structural trends in social housing in Portugal, while relating it with its welfare state regime nature, namely its incipient and tardy character, one that is predominantly oriented towards sectors other than housing. Having other European countries as reference, with different welfare state regimes, we will then point substantive differences in dimension, weight, access forms and target public in this housing sector. Consequently, our main argument revolves around the consequences of a fragile public investment in this domain, which is further channelled in a disparate and bipolar way between a small public promotion of social housing and the incentive to homeownership. We chiefly discuss, as a consequence of this model, the narrowing profile of social housing publics, in a spatially (and temporally) concentrated rationale, gathering individuals with common vulnerability features, lacking the ability to engage in positive residential and social mobility paths. Secondly, we discuss how the current economic and financial crisis, along with profound sociodemographic and labour market changes, determines academics and policy-makers to rethink housing policies and the very role of the state. on the one hand, we are faced with the drastic reduction of state resources and its investment capacity; on the other hand, there is the emergence of new housing needs, as a result of the crisis and also due to more structural economic and social transformations. This context, not only in Portugal but also in Europe, jeopardises policies and housing systems as we now them so far, reintroducing the argument over access (and affordability) to housing by more heterogeneous groups than the common profile of social housing beneficiaries at the moment. We therefore question the role of the state, the rationale and articulation possibilities with other actors and sectors, the financing model and de variety of audiences for whom the right to housing is not yet (or not anymore) guaranteed.FCTinfo:eu-repo/semantics/publishedVersio

The Boltzmann Equation in Scalar Field Theory

We derive the classical transport equation, in scalar field theory with a V(phi) interaction, from the equation of motion for the quantum field. We obtain a very simple, but iterative, expression for the effective action which generates all the n-point Green functions in the high-temperature limit. An explicit closed form is given in the static case.Comment: 10 pages, using RevTeX (corrected TeX misprints