A Reduced Semantics for Deciding Trace Equivalence

Many privacy-type properties of security protocols can be modelled using trace equivalence properties in suitable process algebras. It has been shown that such properties can be decided for interesting classes of finite processes (i.e., without replication) by means of symbolic execution and constraint solving. However, this does not suffice to obtain practical tools. Current prototypes suffer from a classical combinatorial explosion problem caused by the exploration of many interleavings in the behaviour of processes. M\"odersheim et al. have tackled this problem for reachability properties using partial order reduction techniques. We revisit their work, generalize it and adapt it for equivalence checking. We obtain an optimisation in the form of a reduced symbolic semantics that eliminates redundant interleavings on the fly. The obtained partial order reduction technique has been integrated in a tool called APTE. We conducted complete benchmarks showing dramatic improvements.Comment: Accepted for publication in LMC

Nonperturbative and spin effects in the central exclusive production of tensor χc(2+)\chi_c(2^+) meson

We discuss central exclusive production (CEP) of the tensor $\chi_c(2^{+})$ meson in proton-(anti)proton collisions at Tevatron, RHIC and LHC energies. The amplitude for the process is derived within the $k_t$-factorisation approach. Differential and total cross sections are calculated for several unintegrated gluon distributions (UGDFs). We compare exclusive production of all charmonium states $\chi_c(0^+),\,\chi_c(1^+)$ and $\chi_c(2^+)$. Equally good description of the recent Tevatron data is achieved both with Martin-Ryskin phenomenological UGDF and UGDF based on unified BFKL-DGLAP approach. Unlike for Higgs production, the main contribution to the diffractive amplitude of heavy quarkonia comes from nonperturbative region of gluon transverse momenta Q_{\perp}<1\,\GeV. At $y \approx$ 0, depending on UGDF we predict the contribution of $\chi_c(1^+,2^+)$ to the $J/\Psi + \gamma$ channel to be comparable or larger than that of the $\chi_c(0^+)$ one. This is partially due to a significant contribution from lower polarization states $\lambda=0$ for $\chi_c(1^+)$ and $\lambda=0,\,\pm 1$ for $\chi_c(2^+)$ meson. Corresponding theoretical uncertainties are discussed.Comment: 18 pages, 12 figures, discrepancies with Durham group results clarified, numerics corrected, basic conclusions unchanged, acknowledgements adde

Beam element verification for 3D elastic steel frame analysis

The paper describes the attributes that should be possessed by a benchmark example for verifying the beam elements used to carry out 3D linear buckling analysis and 3D second-order elastic analysis of steel frames. Based on the attributes described, the paper proposes a suite of benchmark examples selected from the literature. The necessary features of a beam element required to pass the proposed benchmark problems are given, and beam elements that possess these features are cited. The paper also explains the merits of linear buckling analysis examples, and provides a commentary on two well-known examples

Runtime Verification Of SQL Correctness Properties with YR-DB-RUNTIME-VERIF

Software correctness properties are essential to maintain quality by continuous and regressive inte- gration testing, as well as runtime monitoring the program after customer deployment. This paper presents an effective and lightweight C ++ program verification framework: YR_DB_RUNTIME_VERIF, to check SQL (Structure Query Language) [1] software correctness properties specified as temporal safety properties [2]. A temporal safety property specifies what behavior shall not occur, in a software, as sequence of program events. YR_DB_RUNTIME_VERIF allows specification of a SQL temporal safety property by means of a very small state diagram mealy machine [3]. In YR_DB_RUNTIME_VERIF, a spec- ification characterizes effects of program events (via SQL statements) on database table columns by means of set interface operations (∈, ∈), and, enable to check these characteristics hold or not at runtime. Integration testing is achieved for instance by expressing a state diagram that encompasses both Graphical User Interface (GUI) states and MySQL [4] databases queries that glue them. For example, a simple specification would encompass states between ’Department administration’ and ’Stock listing’ GUI interfaces, and transitions between them by means of MySQL databases oper- ations. YR_DB_RUNTIME_VERIF doesn’t generate false warnings; YR_DB_RUNTIME_VERIF specifications are not desirable (forbidden) specifications (fail traces). This paper focuses its examples on MySQL database specifications, labeled as states diagrams events, for the newly developed and FOSS (Free and Open Source Software) Enterprise Resource Planing Software YEROTH–ERP–3.0 [5].PROF. DR.-ING. DIPL.-INF. xavier noumbissi noundo

Global surpluses of spin-base invariant fermions

The spin-base invariant formalism of Dirac fermions in curved space maintains the essential symmetries of general covariance as well as similarity transformations of the Clifford algebra. We emphasize the advantages of the spin-base invariant formalism both from a conceptual as well as from a practical viewpoint. This suggests that local spin-base invariance should be added to the list of (effective) properties of (quantum) gravity theories. We find support for this viewpoint by the explicit construction of a global realization of the Clifford algebra on a 2-sphere which is impossible in the spin-base non-invariant vielbein formalism.Comment: 6 page