138 research outputs found
Numerical study of vortex system quantum melting
We report a numerical study of the vortex system in the two dimensional
II-type superconductors. We have proposed a phenomenological model that takes
into account quantum fluctuations of Abrikosov's vortices. The results of the
quantum Monte-Carlo simulations by the SSE algorithm show that the thermal
fluctuations are dominated by quantum fluctuations at low temperatures. In
particular, we demonstrate the possibility of the quantum melting transition
for vortex system in the temperature region where thermal melting transition is
improbable
Blue luminescence of Au nanoclusters embedded in silica matrix
Photoluminescence study using the 325 nm He-Cd excitation is reported for the
Au nanoclusters embedded in SiO2 matrix. Au clusters are grown by ion beam
mixing with 100 KeV Ar+ irradiation on Au [40 nm]/SiO2 at various fluences and
subsequent annealing at high temperature. The blue bands above ~3 eV match
closely with reported values for colloidal Au nanoclusters and supported Au
nanoislands. Radiative recombination of sp electrons above Fermi level to
occupied d-band holes are assigned for observed luminescence peaks. Peaks at
3.1 eV and 3.4 eV are correlated to energy gaps at the X- and L-symmetry
points, respectively, with possible involvement of relaxation mechanism. The
blue shift of peak positions at 3.4 eV with decreasing cluster size is reported
to be due to the compressive strain in small clusters. A first principle
calculation based on density functional theory using the full potential linear
augmented plane wave plus local orbitals (FP-LAPW+LO) formalism with
generalized gradient approximation (GGA) for the exchange correlation energy is
used to estimate the band gaps at the X- and L-symmetry points by calculating
the band structures and joint density of states (JDOS) for different strain
values in order to explain the blueshift of ~0.1 eV with decreasing cluster
size around L-symmetry point.Comment: 13 pages, 7 Figures Only in PDF format; To be published in J. of
Chem. Phys. (Tentative issue of publication 8th December 2004
Universal SSE algorithm for Heisenberg model and Bose Hubbard model with interaction
We propose universal SSE method for simulation of Heisenberg model with
arbitrary spin and Bose Hubbard model with interaction. We report on the first
calculations of soft-core bosons with interaction by the SSE method. Moreover
we develop a simple procedure for increase efficiency of the algorithm. From
calculation of integrated autocorrelation times we conclude that the method is
efficient for both models and essentially eliminates the critical slowing down
problem.Comment: 6 pages, 5 figure
poST
Publisher Copyright: AuthorThis paper presents the core concepts for the poST language - a process-oriented extension of the IEC 61131-3 Structured Text (ST) language which intends to provide a conceptual consistency of the PLC source code with technological description of the plant operating procedure. The poST can be seamlessly used as a textual programming language for complex PLC software in the context of IEC 61131-3 (3rd Edition). The language combines the advantages of FSM-based programming with the conventional syntax of the ST language which would facilitate its adoption. The poST language assumes that a poST-program is a set of weakly connected concurrent processes, structurally and functionally corresponding to the technological description of the plant. Each process is specified by a sequential set of states. The states are specified by a set of the ST constructs, extended by TIMEOUT operation, SET STATE operation, and START / STOP / check state operations to communicate with other processes. The paper describes the basic syntax of the poST language, demonstrates the usage of the poST language by developing control software for an elevator, and compares the development in poST with pure Structured Text.Peer reviewe
Test of a simple and flexible S8 model molecule in alpha-s8 crystals
Alpha S8 is the most stable crystalline form, at ambient pressure and
temperature (STP), of elemental sulfur. In this paper we analyze the zero
pressure low temperature part of the phase diagram of this crystal, in order to
test a simple and flexible model molecule. The calculations consist in a series
of molecular dynamics (MD) simulations, performed in the constant pressure-
constant temperature ensemble. Our calculations show that this model, that
gives good results for three crystalline phases at STP and T>~300 K, fails at
low temperatures, predicting a structural phase transition at 200 K where there
should be none.Comment: 6 pages, 4 figures, submitted to Chem. Phys. Lett, a figure change
Temporal Logic for Programmable Logic Controllers
We address the formal verification of the control software of critical systems, i.e., ensuring the absence of design errors in a system with respect to requirements. Control systems are usually based on industrial controllers, also known as Programmable Logic Controllers (PLCs). A specific feature of a PLC is a scan cycle: 1) the inputs are read, 2) the PLC states change, and 3) the outputs are written. Therefore, in order to formally verify PLC, e.g., by model checking, it is necessary to describe the transition system taking into account this specificity and reason both in terms of state transitions within a cycle and in terms of larger state transitions according to the scan-cyclic semantics. We propose a formal PLC model as a hyperprocess transition system and temporal cycle-LTL logic based on LTL logic for formulating PLC property. A feature of the cycle-LTL logic is the possibility of viewing the scan cycle in two ways: as the effect of the environment (in particular, the control object) on the control system and as the effect of the control system on the environment. For both cases we introduce modified LTL temporal operators. We also define special modified LTL temporal operators to specify inside properties of scan cycles. We describe the translation of formulas of cycle-LTL into formulas of LTL, and prove its correctness. This implies the possibility ofmodel checking requirements expressed in logic cycle-LTL, by using well-known model checking tools with LTL as specification logic, e.g., Spin. We give the illustrative examples of requirements expressed in the cycle-LTL logic
Application of Raman spectroscopy to study the inactivation process of bacterial microorganisms
Raman spectroscopy (RS) is one of the promising approaches for structural and functional studies of various biological
objects, including bacterial microorganisms. Both traditional biochemical tests and genetic methods which require
expensive reagents, consumables and are time-consuming are used for bacterial analysis. Spectroscopic methods are
positioned as noninvasive, highly sensitive, and requiring minimal sample preparation. In this work we investigated
the possibility of using the RS method using optical sensors based on gold anisotropic nanoparticles. The applicability
of the method was demonstrated by studying the effect of a broad-spectrum cephalosporin antibiotic and an extract of
Viburnum opulus L (VO) on Escherichia coli (E. Coli) colonies. The studies were performed by Raman spectroscopy
using a Virsa spectrometer (Renishaw). Raman signal amplification was carried out using two original optical sensors
proposed by the authors. To create sensors, we used a chemical method of depositing gold nanostars on APTES-modified
quartz glasses and a physical method for creating sensors based on anodizing titanium surfaces. The results of the study
showed the high sensitivity and information content of the proposed method. The possibility of using the RS method
for studying the inactivation of bacterial microorganisms is shown. Spectral Raman bands of E. Coli were determined
and identified before and after exposure to VO extract and antibiotic as a control. A decrease in the intensity of spectral
modes corresponding to amino acids and purine metabolites was found in the average Raman spectrum of E. Coli
after exposure to VO extract. For the first time, a study of the antimicrobial effect of an aqueous extract of VO fruits
was carried out by the method of Raman scattering. It has been shown that the use of plant extracts, including VO fruit
extracts, to inactivate the vital activity of bacterial colonies is a promising approach to the search for new alternative
antibacterial agents. The results obtained are in good agreement with the already known scientific studies and confirm
the effectiveness of the proposed method
ΠΠ΅ΡΠΎΠ΄Ρ ΡΠΏΠ΅ΡΠΈΠ°Π»ΠΈΠ·Π°ΡΠΈΠΈ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ², ΠΎΡΠΈΠ΅Π½ΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ Π½Π° Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ
User-friendly formal specifications and verification of parallel and distributed systems from various subject fields, such as automatic control, telecommunications, business processes, are active research topics due to its practical significance. In this paper, we present methods for the development of verification-oriented domain-specific process ontologies which are used to describe parallel and distributed systems of subject fields. One of the advantages of such ontologies is their formal semantics which make possible formal verification of the described systems. Our method is based on the abstract verification-oriented process ontology. We use two methods of specialization of the abstract process ontology. The declarative method uses the specialization of the classes of the original ontology, introduction of new declarative classes, as well as use of new axioms system, which restrict the classes and relations of the abstract ontology. The constructive method uses semantic markup and pattern matching techniques to link sublect fields with classes of the abstract process ontology. We provide detailed ontological specifications for these techniques. Our methods preserve the formal semantics of the original process ontology and, therefore, the possibility of applying formal verification methods to the specializedΒ process ontologies. We show that the constructive method is a refinement of the declarative method. The construction of ontology of the typical elements of automatic control systems illustrates our methods: we develop a declarative description of the classes and restrictions for the specialized ontology in the ProtΒ΄egΒ΄e system in the OWL language using the deriving rules written in the SWRL language and we construct the system of semantic markup templates which implements typical elements of automatic control systems.Π£Π΄ΠΎΠ±Π½Π°Ρ Π΄Π»Ρ ΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΠ΅Π»Ρ ΡΠΎΡΠΌΠ°Π»ΡΠ½Π°Ρ ΡΠΏΠ΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΠΈ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΠΏΠ°ΡΠ°Π»Π»Π΅Π»ΡΠ½ΡΡ
ΠΈ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»ΡΠ½Π½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ, ΠΏΡΠΈΠ½Π°Π΄Π»Π΅ΠΆΠ°ΡΠΈΡ
ΡΠ°Π·Π»ΠΈΡΠ½ΡΠΌ ΠΏΡΠ΅Π΄ΠΌΠ΅ΡΠ½ΡΠΌ ΠΎΠ±Π»Π°ΡΡΡΠΌ, ΡΠ°ΠΊΠΈΠΌ ΠΊΠ°ΠΊ ΡΠΈΡΡΠ΅ΠΌΡ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ, ΡΠ΅Π»Π΅ΠΊΠΎΠΌΠΌΡΠ½ΠΈΠΊΠ°ΡΠΈΠΈ, Π±ΠΈΠ·Π½Π΅Ρ-ΠΏΡΠΎΡΠ΅ΡΡΡ, ΡΠ²Π»ΡΡΡΡΡ Π°ΠΊΡΠΈΠ²Π½ΡΠΌΠΈ ΡΠ΅ΠΌΠ°ΠΌΠΈ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ Π² ΡΠΈΠ»Ρ ΠΈΡ
ΠΏΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π·Π½Π°ΡΠΈΠΌΠΎΡΡΠΈ. Π ΡΡΠΎΠΉ ΡΡΠ°ΡΡΠ΅ ΠΌΡ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΠ΅ΠΌ ΠΌΠ΅ΡΠΎΠ΄Ρ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ ΡΠΏΠ΅ΡΠΈΠ°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΠΎΡΠΈΠ΅Π½ΡΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
Π½Π° Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΉ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ², ΠΊΠΎΡΠΎΡΡΠ΅ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΡΡ Π΄Π»Ρ ΠΎΠΏΠΈΡΠ°Π½ΠΈΡ ΠΏΠ°ΡΠ°Π»Π»Π΅Π»ΡΠ½ΡΡ
ΠΈ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ ΠΏΡΠ΅Π΄ΠΌΠ΅ΡΠ½ΡΡ
ΠΎΠ±Π»Π°ΡΡΠ΅ΠΉ. ΠΠ΄Π½ΠΈΠΌ ΠΈΠ· ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ² ΡΠ°ΠΊΠΈΡ
ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΉ ΡΠ²Π»ΡΠ΅ΡΡΡ ΠΈΡ
ΡΠΎΡΠΌΠ°Π»ΡΠ½Π°Ρ ΡΠ΅ΠΌΠ°Π½ΡΠΈΠΊΠ°, ΠΊΠΎΡΠΎΡΠ°Ρ Π΄Π΅Π»Π°Π΅Ρ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΠΉ ΡΠΎΡΠΌΠ°Π»ΡΠ½ΡΡ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΠΎΠΏΠΈΡΠ°Π½Π½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ. ΠΠ°Ρ ΠΌΠ΅ΡΠΎΠ΄ ΠΎΡΠ½ΠΎΠ²Π°Π½ Π½Π° Π°Π±ΡΡΡΠ°ΠΊΡΠ½ΠΎΠΉ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ², ΠΎΡΠΈΠ΅Π½ΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ Π½Π° Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ. ΠΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌ Π΄Π²Π° ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠΏΠ΅ΡΠΈΠ°Π»ΠΈΠ·Π°ΡΠΈΠΈ Π°Π±ΡΡΡΠ°ΠΊΡΠ½ΠΎΠΉ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ². ΠΠ΅ΠΊΠ»Π°ΡΠ°ΡΠΈΠ²Π½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΡΠΏΠ΅ΡΠΈΠ°Π»ΠΈΠ·Π°ΡΠΈΠΈ ΠΊΠ»Π°ΡΡΠΎΠ² ΠΈΡΡ
ΠΎΠ΄Π½ΠΎΠΉ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ, Π²Π²Π΅Π΄Π΅Π½ΠΈΡ Π½ΠΎΠ²ΡΡ
Π΄Π΅ΠΊΠ»Π°ΡΠ°ΡΠΈΠ²Π½ΡΡ
ΠΊΠ»Π°ΡΡΠΎΠ², Π° ΡΠ°ΠΊΠΆΠ΅ ΡΠΈΡΡΠ΅ΠΌΡ Π°ΠΊΡΠΈΠΎΠΌ Π·Π°Π΄Π°ΡΡ ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½ΠΈΡ Π΄Π»Ρ ΠΊΠ»Π°ΡΡΠΎΠ² ΠΈ ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΉ Π°Π±ΡΡΡΠ°ΠΊΡΠ½ΠΎΠΉ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ. ΠΠΎΠ½ΡΡΡΡΠΊΡΠΈΠ²Π½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅Ρ ΡΠ΅Ρ
Π½ΠΈΠΊΠΈ ΡΠ΅ΠΌΠ°Π½ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ°Π·ΠΌΠ΅ΡΠΊΠΈ ΠΈ ΡΠΎΠΏΠΎΡΡΠ°Π²Π»Π΅Π½ΠΈΡ Ρ ΠΎΠ±ΡΠ°Π·ΡΠΎΠΌ, ΡΡΠΎΠ±Ρ ΡΠ²ΡΠ·Π°ΡΡ ΠΏΠΎΠ½ΡΡΠΈΡ ΠΏΡΠ΅Π΄ΠΌΠ΅ΡΠ½ΠΎΠΉ ΠΎΠ±Π»Π°ΡΡΠΈ Ρ ΠΊΠ»Π°ΡΡΠ°ΠΌΠΈ Π°Π±ΡΡΡΠ°ΠΊΡΠ½ΠΎΠΉ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ². ΠΡ Π΄Π°ΡΠΌ ΠΏΠΎΠ΄ΡΠΎΠ±Π½ΡΠ΅ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠΏΠ΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΡΡΠΈΡ
ΡΠ΅Ρ
Π½ΠΈΠΊ. ΠΠ°ΡΠΈ ΠΌΠ΅ΡΠΎΠ΄Ρ ΡΠΎΡ
ΡΠ°Π½ΡΡΡ ΡΠΎΡΠΌΠ°Π»ΡΠ½ΡΡ ΡΠ΅ΠΌΠ°Π½ΡΠΈΠΊΡ ΠΈΡΡ
ΠΎΠ΄Π½ΠΎΠΉ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ² ΠΈ, ΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎ, Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ ΡΠΎΡΠΌΠ°Π»ΡΠ½ΡΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΠΊ ΡΠΏΠ΅ΡΠΈΠ°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΡΠΌ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΡΠΌ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ². ΠΡ ΠΏΠΎΠΊΠ°Π·ΡΠ²Π°Π΅ΠΌ, ΡΡΠΎ ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠ²Π½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΡΠΎΡΠ½Π΅Π½ΠΈΠ΅ΠΌ Π΄Π΅ΠΊΠ»Π°ΡΠ°ΡΠΈΠ²Π½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π°. ΠΠΎΡΡΡΠΎΠ΅Π½ΠΈΠ΅ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ ΡΠΈΠΏΠΎΠ²ΡΡ
ΡΠ»Π΅ΠΌΠ΅Π½ΡΠΎΠ² ΡΠΈΡΡΠ΅ΠΌ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΈΠ»Π»ΡΡΡΡΠΈΡΡΠ΅Ρ Π½Π°ΡΠΈ ΠΌΠ΅ΡΠΎΠ΄Ρ: ΡΠ°Π·ΡΠ°Π±ΠΎΡΠ°Π½ΠΎ Π΄Π΅ΠΊΠ»Π°ΡΠ°ΡΠΈΠ²Π½ΠΎΠ΅ ΠΎΠΏΠΈΡΠ°Π½ΠΈΠ΅ ΠΊΠ»Π°ΡΡΠΎΠ² ΠΈ ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½ΠΈΠΉ ΡΠΏΠ΅ΡΠΈΠ°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ Π² ΡΠΈΡΡΠ΅ΠΌΠ΅ Protege Π½Π° ΡΠ·ΡΠΊΠ΅ OWL Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΠΏΡΠ°Π²ΠΈΠ» Π²ΡΠ²ΠΎΠ΄Π° Π½Π° ΡΠ·ΡΠΊΠ΅ SWRL ΠΈ ΠΏΠΎΡΡΡΠΎΠ΅Π½Π° ΡΠΈΡΡΠ΅ΠΌΠ° ΡΠ°Π±Π»ΠΎΠ½ΠΎΠ² ΡΠ΅ΠΌΠ°Π½ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ°Π·ΠΌΠ΅ΡΠΊΠΈ, ΠΊΠΎΡΠΎΡΠ°Ρ ΡΠ΅Π°Π»ΠΈΠ·ΡΠ΅Ρ ΡΠΈΠΏΠΎΠ²ΡΠ΅ ΡΠ»Π΅ΠΌΠ΅Π½ΡΡ ΡΠΈΡΡΠ΅ΠΌ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ
First principles high throughput screening of oxynitrides for water-splitting photocatalysts
In this paper, we present a first principles high throughput screening system to search for new water-splitting photocatalysts. We use the approach to screen through nitrides and oxynitrides. Most of the known photocatalytic materials in the screened chemical space are reproduced. In addition, sixteen new materials are suggested by the screening approach as promising photocatalysts, including three binary nitrides, two ternary oxynitrides and eleven quaternary oxynitrides.United States. Dept. of Energy (contract DE-FG02-96ER4557)National Science Foundation (U.S.) (TeraGrid resources under Grant No. TG-DMR970008S)Pittsburgh Supercomputing CenterUniversity of Texas at Austin. Texas Advanced Computing CenterEni-MIT Solar Frontiers Cente
Π’Π΅ΠΌΠΏΠΎΡΠ°Π»ΡΠ½Π°Ρ Π»ΠΎΠ³ΠΈΠΊΠ° Π΄Π»Ρ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠΈΡΡΠ΅ΠΌΡΡ Π»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ ΠΊΠΎΠ½ΡΡΠΎΠ»Π»Π΅ΡΠΎΠ²
We address the formal verification of the control software of critical systems, i.e., ensuring the absence of design errors in a system with respect to requirements. Control systems are usually based on industrial controllers, also known as Programmable Logic Controllers (PLCs). A specific feature of a PLC is a scan cycle: 1) the inputs are read, 2) the PLC states change, and 3) the outputs are written. Therefore, in order to formally verify PLC, e.g., by model checking, it is necessary to describe the transition system taking into account this specificity and reason both in terms of state transitions within a cycle and in terms of larger state transitions according to the scan-cyclic semantics. We propose a formal PLC model as a hyperprocess transition system and temporal cycle-LTL logic based on LTL logic for formulating PLC property. A feature of the cycle-LTL logic is the possibility of viewing the scan cycle in two ways: as the effect of the environment (in particular, the control object) on the control system and as the effect of the control system on the environment. For both cases we introduce modified LTL temporal operators. We also define special modified LTL temporal operators to specify inside properties of scan cycles. We describe the translation of formulas of cycle-LTL into formulas of LTL, and prove its correctness. This implies the possibility ofmodel checking requirements expressed in logic cycle-LTL, by using well-known model checking tools with LTL as specification logic, e.g., Spin. We give the illustrative examples of requirements expressed in the cycle-LTL logic.ΠΡ ΠΈΡΡΠ»Π΅Π΄ΡΠ΅ΠΌ ΡΠΎΡΠΌΠ°Π»ΡΠ½ΡΡ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΡΠΏΡΠ°Π²Π»ΡΡΡΠ΅Π³ΠΎ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΠΎΠ³ΠΎ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΈΡΡΠ΅ΠΌ, Ρ. Π΅. ΠΏΡΠΎΠ²Π΅ΡΠΊΡ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΡ ΡΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΡΠ΅ΠΌΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ ΠΏΡΠ΅Π΄ΡΡΠ²Π»Π΅Π½Π½ΡΠΌ ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΡΠΌ. ΠΠ°ΠΆΠ½Π΅ΠΉΡΠΈΠΉ ΠΊΠ»Π°ΡΡ ΡΠΏΡΠ°Π²Π»ΡΡΡΠ΅Π³ΠΎ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΠΎΠ³ΠΎ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ ΡΠΎΡΡΠ°Π²Π»ΡΡΡ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΡ Π΄Π»Ρ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠΈΡΡΠ΅ΠΌΡΡ
Π»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΎΠ½ΡΡΠΎΠ»Π»Π΅ΡΠΎΠ² (ΠΠΠ). ΠΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΡΡ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌ ΠΠΠ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠΈΠΊΠ» ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ: 1) ΡΡΠΈΡΡΠ²Π°ΡΡΡΡ Π²Ρ
ΠΎΠ΄Ρ, 2) ΠΈΠ·ΠΌΠ΅Π½ΡΡΡΡΡ ΡΠΎΡΡΠΎΡΠ½ΠΈΡ ΠΠΠ ΠΈ 3) Π·Π°ΠΏΠΈΡΡΠ²Π°ΡΡΡΡ Π²ΡΡ
ΠΎΠ΄Ρ. ΠΠΎΡΡΠΎΠΌΡ Π΄Π»Ρ ΡΠΎΡΠΌΠ°Π»ΡΠ½ΠΎΠΉ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌ ΠΠΠ Π½ΡΠΆΠ½Π° Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΎΠΏΠΈΡΡΠ²Π°ΡΡ ΡΡΠΈΡΡΠ²Π°ΡΡΠΈΠ΅ ΡΡΡ ΡΠΏΠ΅ΡΠΈΡΠΈΠΊΡ ΡΠΈΡΡΠ΅ΠΌΡ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄ΠΎΠ², Π° ΡΠ°ΠΊΠΆΠ΅ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΡΡ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΡΠΈΡΡΠ΅ΠΌ, ΠΌΠΎΠ΄Π΅Π»ΠΈΡΡΡΡΠΈΡ
ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΡ ΠΠΠ, ΠΊΠ°ΠΊ ΠΎΡΠ½ΠΎΡΠΈΡΠ΅Π»ΡΠ½ΠΎ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄ΠΎΠ² Π²Π½ΡΡΡΠΈ ΡΠΈΠΊΠ»Π°, ΡΠ°ΠΊ ΠΈ ΠΎΡΠ½ΠΎΡΠΈΡΠ΅Π»ΡΠ½ΠΎ Π±ΠΎΠ»Π΅Π΅ ΠΊΡΡΠΏΠ½ΡΡ
ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄ΠΎΠ² Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΡΠ΅ΠΌΠ°Π½ΡΠΈΠΊΠΎΠΉ ΡΠΈΠΊΠ»Π° ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ. ΠΡ ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅ΠΌ ΡΠΎΡΠΌΠ°Π»ΡΠ½ΡΡ ΠΌΠΎΠ΄Π΅Π»Ρ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΡ ΠΠΠ ΠΊΠ°ΠΊ ΡΠΈΡΡΠ΅ΠΌΡ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄ΠΎΠ² Π³ΠΈΠΏΠ΅ΡΠΏΡΠΎΡΠ΅ΡΡΠΎΠ² ΠΈ ΡΠ΅ΠΌΠΏΠΎΡΠ°Π»ΡΠ½ΡΡ Π»ΠΎΠ³ΠΈΠΊΡ cycle-LTL Π΄Π»Ρ ΡΠΎΡΠΌΠ°Π»ΠΈΠ·Π°ΡΠΈΠΈ ΡΠ²ΠΎΠΉΡΡΠ² ΠΠΠ. ΠΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΡΡ Π»ΠΎΠ³ΠΈΠΊΠΈ cycle-LTL ΡΠ²Π»ΡΠ΅ΡΡΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΡΠΈΡΡΠ΅ΠΌ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ Π΄Π²ΠΎΡΠΊΠΈΠΌ ΠΎΠ±ΡΠ°Π·ΠΎΠΌ: Π²ΠΎΠ·Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ ΠΎΠΊΡΡΠΆΠ΅Π½ΠΈΡ Π½Π° ΡΠΈΡΡΠ΅ΠΌΡ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΈ Π²ΠΎΠ·Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ ΡΠΈΡΡΠ΅ΠΌΡ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ Π½Π° ΠΎΠΊΡΡΠΆΠ΅Π½ΠΈΠ΅. ΠΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΠΌ ΠΌΠΎΠ΄ΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΡΡ
ΡΠ΅ΠΌΠΏΠΎΡΠ°Π»ΡΠ½ΡΡ
ΠΎΠΏΠ΅ΡΠ°ΡΠΎΡΠΎΠ² Π»ΠΎΠ³ΠΈΠΊΠΈ LTL Π΄Π»Ρ ΠΊΠ°ΠΆΠ΄ΠΎΠ³ΠΎ ΠΈΠ· ΡΡΠΈΡ
ΡΠ»ΡΡΠ°Π΅Π², Π° ΡΠ°ΠΊΠΆΠ΅ Π΄Π»Ρ ΡΠ²ΠΎΠΉΡΡΠ² Π²Π½ΡΡΡΠΈ ΡΠΈΠΊΠ»Π° ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ. Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΏΡΠΈΠΌΠ΅ΡΡ ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΠΉ, ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΡΡ
Π² Π½Π°ΡΠ΅ΠΉ Π»ΠΎΠ³ΠΈΠΊΠ΅. ΠΠΏΠΈΡΠ°Π½Π° ΡΡΠ°Π½ΡΠ»ΡΡΠΈΡ ΡΠΎΡΠΌΡΠ» cycle-LTL Π² ΡΠΎΡΠΌΡΠ»Ρ LTL ΠΈ ΠΏΠΎΠΊΠ°Π·Π°Π½Π° Π΅Ρ ΠΊΠΎΡΡΠ΅ΠΊΡΠ½ΠΎΡΡΡ. ΠΠΎΠΊΠ°Π·Π°Π½Π° Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΡΠ²Π΅Π΄Π΅Π½ΠΈΡ Π·Π°Π΄Π°ΡΠΈ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΏΡΠΎΠ²Π΅ΡΠΊΠΈ ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ Π΄Π»Ρ ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΠΉ, ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΡΡ
Π² Π»ΠΎΠ³ΠΈΠΊΠ΅ cycle-LTL, ΠΊ Π·Π°Π΄Π°ΡΠ΅ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΠΉ, ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΡΡ
Π² ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΠΎΠΉ Π»ΠΎΠ³ΠΈΠΊΠ΅ LTL
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