Static analysis of Linear Logic programming

Linear Logic is gaining momentum in computer science because it offers a unified framework and a common vocabulary for studying and analyzing different aspects of programming and computation. We focus here on models where computation is identified with proof search in the sequent system of Linear Logic. A proof normalization procedure, called “focusing”, has been proposed to make the problem of proof search tractable. Correspondingly, there is a normalization procedure mapping formulae of Linear Logic into a syntactic fragment of that logic, calledLinLog, where the focusing normalization for proofs can be most conveniently expressed. In this paper, we propose to push this compilation/normalization process further, by applying abstract interpretation and partial evaluation techniques to (focused) proofs inLinLog. These techniques provide information concerning the evolution of the computational resources (formulae) during the execution (proof construction). The practical outcome that we expect from this theoretical effort is the definition of a general tool for statically analyzing and reasoning about the runtime behavior of programs in frameworks where computations can be accounted for in terms of proof search in Linear Logic.     

Phytoplankton size-distribution and community structure in relation to mucilage occurrence in the northern Adriatic Sea

The spatial and temporal variations of pico-, nano- and microphytoplankton abundance and composition were investigated over a 37 month period, focusing on the ecological role of different size classes of phytoplankton, and on the changes of the community structure that might occur during periods when large mucilage macroaggregates appear. Samples were collected monthly from June 1999 to July 2002 at 11 stations, along three transects covering the northern Adriatic basin. Highest abundances were observed in late-winter/spring for microphytoplankton (mainly diatoms), in spring-summer for nanophytoplankton, and in summer for picophytoplankton. The autotrophic component was more abundant in the summers of 2000 and 2002 (when large mucilage aggregates occurred) than in the summers of 1999 and 2001 (when a massive phenomenon was not observed). This increase was statistically significant for pico-, nano- and, among microphytoplankton, only for dinoflagellates. Blooms of picophytoplankton were often observed at the bottom layer during mucilage summers. The microphytoplankton community during mucilage phenomena was characterized by a species composition (Chaetoceros spp., Cerataulina pelagica, Pseudo-nitzschia delicatissima, P. pseudodelicatissima, Cylindrotheca closterium, Dactyliosolen fragilissimus) comparable to that observed in summers without extensive mucilage occurrence. However, some species appeared with significantly higher densities in the summers of 2000 and 2002: Ceratium furca, C. closterium, Oxytoxum spp., Hemiaulus hauckii and Gonyaulax fragilis. Microscopic observation of aggregates revealed that the microphytoplankton species composition inside the aggregates was comparable to that observed in the water column, with an enrichment of opportunistic species such as C. closterium and P. delicatissima. The presence of mucilage aggregates affects the phytoplankton populations in the water column, even when aggregates are at early stages. It seems that there is a mutual relationship between phytoplankton and aggregates, i.e., several diatom and dinoflagellate species may contribute to the aggregate formation and enlargement, but mucilage aggregates themselves may also affect the phytoplankton populations, allowing the development of a rich diatom community and in general enhancing nanophytoplankton growth.     

Transmission Performance of MC-CDMA Hybrid Fiber-Radio Systems

This paper reports an analysis of the transmission performance of a hybrid broadband access system consisting of a fiber optic feeder and a millimeter-wave radio channel in the last mile. It is also assumed that the system adopts the multi-carrier code division multiple access (MC-CDMA) technique, that allows effective radio resource utilization and does not require a strong equalization. The analysis reveals that the impact of non-linear effects, mostly due to the non-linear optical source and secondarily due to non-ideal RF power amplifier characteristics, could prevent the good performance of the system as a whole, and indicates which are the good operating conditions for the systems.     

Determinants of governance structure in alliances: the role of strategic, task and partner uncertainties

Research in transaction cost economics and structural sociologyhas emphasized the role of opportunism and trust in the choicebetween equity and non-equity governance forms in alliances.This paper suggests that the uncertainty surrounding partnercooperation is not straightforwardly predictive of governancestructure in alliances. Instead, task uncertainty and strategicuncertainty associated with the activities performed withinalliances induce coordination and adaptation requirements thatare important determinants of alliance governance, independentlyof partner uncertainty. Support for this view is provided basedon a 12-year panel of alliances formed in the US telecommunications,entertainment and computer industries.     

Knowledge-based relevance filtering for efficient system-level test-based model generation

Test-based model generation by classical automata learning is very expensive. It requires an impractically large number of queries to the system, each of which must be implemented as a system-level test case. Key in the tractability of observation-based model generation are powerful optimizations exploiting different kinds of expert knowledge in order to drastically reduce the number of required queries, and thus the testing effort. In this paper, we present a thorough experimental analysis of the second-order effects between such optimizations in order to maximize their combined impact.     

Determinacy and maximal parallelism in a structured model of parallel computation

The main goal of this paper is the introduction, from a theoretical point of view, of a model specifically studied for the optimization of horizontal microprograms but well suited also to the analysis of microprocessor systems. Moreover, an approach to the design of well-structured and correct parallel programs is given by studying a subset of our schemes (complex structures) and applying to it existing techniques in order to give an algorithm for the maximization of parallelism.     

Special Section on “Leveraging Formal Methods”

This Special Section contains selected papers from ISoLA 2004, the First International Symposium on Leveraging Applications of Formal Methods held in Paphos (Cyprus) October–November 2004. ISoLA 2004 served the need of providing a forum for developers, users, and researchers to discuss issues related to the adoption and use of rigorous tools and methods for the specification, analysis, verification, certification, construction, test, and maintenance of systems from the point of view of their different application domains. The seven selected papers illustrate the intended variety of ISoLA’s scope.     

Partial dealcoholisation of red wines by membrane contactor technique: influence on colour, phenolic compounds and saliva precipitation index

In this study, red wines from different grape varieties (Merlot, Aglianico and Piedirosso) and containing different alcoholic level (from 13.67 to 15.46% v/v) were treated to diminish the alcoholic percentage of 2, 3 and 5% v/v by a polypropylene hollow fibre membrane contactor apparatus. The wines were analysed before and after partial dealcoholisation. Colour indexes and phenolics were analysed by spectrophotometric methods and HPLC. Wine astringency was evaluated by an astringency index based on the ability of treated wines to precipitate salivary proteins (SPI, Saliva Precipitation Index). For all the levels of dealcoholisation studied, changes in chromatic characteristics, Folin–Ciocalteu index and vanillin reactive flavans were below the methodological errors of the analyses. A loss of malvidin 3-monoglucoside was detected after the dealcoholisation process. Decreasing the ethanol content of wines caused an increase in SPI values.     

Effect of Surface Density on the Engineering Properties of High Methoxyl Pectin-Based Edible Films

The effect of pectin surface density (ρ _s) on the engineering properties of high methoxyl (HM) pectin-based edible films was determined in order to explore the role of ρ _s on structure and functional properties. Films at different ρ _s values (2.5, 3.2, 3.8, 4.5, 5.1, 5.8 mg cm⁻²) were analyzed by means of microscopy, thermal, mechanical, and barrier (water vapor permeability WVP, oxygen permeability \textkP_\textO2 {\text{kP}}_{{{\text{O}}_2 }} , carbon dioxide permeability \textkP_\textCO2 {\text{kP}}_{{{\text{CO}}_2 }} ) properties. Microscopy, thermal, and mechanical results showed that by increasing ρ _s from 2.5 to 5.8 mg cm⁻², the film structure does not change. HM pectin-based film has a tensile strength of 20 ± 7 MPa and an elastic modulus (E) equal to 2,400 ± 200 MPa. However, it is quite brittle as the elongation to break (e) is close to 1%. Although the film structure was unaffected by ρ _s, WVP increased with the rise in ρ _s while \textkP_\textO2 {\text{kP}}_{{{\text{O}}_2 }} and \textkP_\textCO2 {\text{kP}}_{{{\text{CO}}_2 }} decreased. On the whole, HM pectin-based film showed barrier properties comparable to biodegradable commercial film and low selectivity.     

HPLC-ESI-MS/MS assessment of the tetrahydro-metabolites of cortisol and cortisone in bovine urine: promising markers of dexamethasone and prednisolone treatment

The effects of long-term administration of low doses of dexamethasone (DX) and prednisolone (PL) on the metabolism of endogenous corticosteroids were investigated in veal calves. In addition to cortisol (F) and cortisone (E), whose interconversion is regulated by 11β-hydroxysteroid dehydrogenases (11βHSDs), special attention was paid to tetrahydrocortisol (THF), allo-tetrahydrocortisol (aTHF), tetrahydrocortisone (THE) and allo-tetrahydrocortisone (aTHE), which are produced from F and E by catalytic activity of 5α and 5β-reductases. A specifically developed HPLC-ESI-MS/MS method achieved the complete chromatographic separation of two pairs of diastereoisomers (THF/aTHF and THE/aTHE), which, with appropriate mass fragmentation patterns, provided an unambiguous conformation. The method was linear (r² > 0.9905; 0.5–25 ng ml^?1), with LOQQ of 0.5 ng ml^?1. Recoveries were in range 75–114%, while matrix effects were minimal. The experimental study was carried out on three groups of male Friesian veal calves: group PL (n = 6, PL acetate 15 mg day^–1 p.o. for 31 days); group DX (n = 5, 5 mg of estradiol (E2) i.m., weekly, and 0.4 mg day^–1 of DX p.o. for 31 days) and a control group (n = 8). Urine was collected before, during (twice) and at the end of treatment. During PL administration, the tetrahydro-metabolite levels decreased gradually and remained low after the suspension of treatment. DX reduced urinary THF that persisted after the treatment, while THE levels decreased during the experiment, but rebounded substantially after the DX was withdrawn. Both DX and PL significantly interfered with the production of F and E, leading to their complete depletion. Taken together, the results demonstrate the influence of DX and PL administration on 11βHSD activity and their impact on dysfunction of the 5-reductase pathway. In conclusion, profiling tetrahydro-metabolites of F and E might serve as an alternative, indirect but reliable, non-invasive procedure for assessing the impact of synthetic glucocorticosteroids administration.