An Approach to Model Checking of Multi-agent Data Analysis

The paper presents an approach to verification of a multi-agent data analysis algorithm. We base correct simulation of the multi-agent system by a finite integer model. For verification we use model checking tool SPIN. Protocols of agents are written in Promela language and properties of the multi-agent data analysis system are expressed in logic LTL. We run several experiments with SPIN and the model.Comment: In Proceedings MOD* 2014, arXiv:1411.345

Autotuning Parallel Programs by Model Checking

The paper presents a new approach to autotuning data-parallel programs. Autotuning is a search for optimal program settings which maximize its performance. The novelty of the approach lies in the use of the model checking method to find the optimal tuning parameters by the method of counterexamples. In our work, we abstract from specific programs and specific processors by defining their representative abstract patterns. Our method of counterexamples implements the following four steps. At the first step, an execution model of an abstract program on an abstract processor is described in the language of a model checking tool. At the second step, in the language of the model checking tool, we formulate the optimality property that depends on the constructed model. At the third step, we find the optimal values of the tuning parameters by using a counterexample constructed during the verification of the optimality property. In the fourth step, we extract the information about the tuning parameters from the counter-example for the optimal parameters. We apply this approach to autotuning parallel programs written in OpenCL, a popular modern language that extends the C language for programming both standard multi-core processors (CPUs) and massively parallel graphics processing units (GPUs). As a verification tool, we use the SPIN verifier and its model representation language Promela, whose formal semantics is good for modelling the execution of parallel programs on processors with different architectures

Алгоритмы для BDI-агентов, основанные на знаниях

Multiagent algorithm is a knowledge-based distributed algorithm that solves some problems by means of cooperative work of agents. From an individual agent's perspective, a multiagent algorithm is a reactive and proactive knowledge/believe-based rational algorithm aimed to achieve an agent's own desires. In the paper we study a couple of knowledge-based multiagent algorithms. One particular algorithm is for a system consisting of agents that arrive one by one (in a non-deterministic order) to a resource center to rent (for a while) one of available desired resources. Available resources are passive, they form a cloud; each of the available resources is lent on demand if there is no race for this resource and returns to the cloud after use. Agents also form a cloud but leave the cloud immediately when they rent a desired resource. The problem is to design a knowledge-based multiagent algorithm, which allows each arriving agent eventually to rent some of desired resources (without race for these resources).Мультиагентный алгоритм — это распределённый алгоритм, основанный на знаниях, который решает некоторую проблему посредством совместной работы агентов. BDI-агент — это агент, обладающий убеждениями (Belief), желаниями (Desire) и намерениями (Intention). С точки зрения такого агента, мультиагентный алгоритм — это алгоритм, основанный на его знаниях и убеждениях, с помощью которого достигается выполнение его желаний посредством последовательного осуществления намерений. Мы считаем также, что агенты реактивны, проактивны и рациональны. В этой статье мы предлагаем и изучаем два мультиагентных алгоритма, которые основаны на знаниях. В частности, мы предлагаем мультиагентный алгоритм для следующей задачи аренды ресурсов. Система состоит из агентов, которые прибывают один за другим в произвольном порядке в ресурсный центр, чтобы арендовать один из предоставляемыхресурсов. Предоставляемые ресурсы пассивны, они образуют облако. Если за ресурс нет конкуренции, то он предоставляется по запросу, и возвращается в облако после использования. Агенты также образуют облако, но когда арендуют нужный ресурс, то сразу же покидают ресурсный центр. Задача состоит в разработке мультиагентного алгоритма, основанного на знаниях, обладающего следующим свойством корректности: каждый прибывающий в ресурсный центр агент рано или поздно арендует какой-либо из запрашиваемых ресурсов без конкуренции за этот ресурс в данный момент

Подход к автонастройке параллельных программ методом проверки моделей

The paper presents a new approach to autotuning data-parallel programs. Autotuning is a search for optimal program settings which maximize its performance. The novelty of the approach lies in the use of the model checking method to find the optimal tuning parameters by the method of counterexamples. In our work, we abstract from specific programs and specific processors by defining their representative abstract patterns. Our method of counterexamples implements the following four steps. At the first step, an execution model of an abstract program on an abstract processor is described in the language of a model checking tool. At the second step, in the language of the model checking tool, we formulate the optimality property that depends on the constructed model. At the third step, we find the optimal values of the tuning parameters by using a counterexample constructed during the verification of the optimality property. In the fourth step, we extract the information about the tuning parameters from the counter-example for the optimal parameters. We apply this approach to autotuning parallel programs written in OpenCL, a popular modern language that extends the C language for programming both standard multi-core processors (CPUs) and massively parallel graphics processing units (GPUs). As a verification tool, we use the SPIN verifier and its model representation language Promela, whose formal semantics is good for modelling the execution of parallel programs on processors with different architectures.В этой статье представлен новый подход к автонастройке программ, параллельных по данным. Автонастройка -- это поиск оптимальных параметров настройки программы, при которых её производительность оказывается максимальной. Новизна подхода состоит в использовании метода проверки моделей для поиска оптимальных параметров настройки методом контрпримеров. В нашей работе мы абстрагируемся от конкретных программ и конкретных процессоров, задавая их представительные абстрактные шаблоны. Наш метод контрпримеров состоит в реализации следующих четырёх шагов. На первом шаге на языке инструмента проверки моделей задаётся модель исполнения абстрактной программы на абстрактном процессоре. На втором шаге на языке инструмента проверки моделей формулируем свойство оптимальности, зависящее от построенной модели. На третьем шаге подбираем оптимальные значения параметров настройки посредством использования контрпримеров, построенных в ходе верификации свойства оптимальности. На четвёртом шаге извлекаем информацию о параметрах настройки из контрпримера для оптимальных параметров. Мы применяем этот подход к автонастройке параллельных программ, написанных на языке OpenCL -- современном популярном языке, который расширяет язык C для программирования как обычных многоядерных процессоров (CPU), так и массивно-параллельных графических процессоров (GPU). В качестве инструмента верификации мы используем верификатор SPIN и его язык представления моделей Promela, формальная семантика которого позволяет моделировать исполнение параллельных программ на процессорах с различной архитектурой

New hybrid materials on the basis of magnetite and magnetite-gold nanoparticles for biomedical application

During last decades magnetite nanoparticles (NPs) attract a deep interest of scientists due to their potential application in therapy and diagnostics. However, magnetite nanoparticles are toxic and non-stable in physiological conditions. To solve these problems, we decided to create two types of hybrid systems based on magnetite and gold which is inert and biocompatible: gold as a shell material (first type) and gold as separate NPs interfacially bond to magnetite NPs (second type). An additional advantage of gold is the possibility of its functionalization with a variety of sulphur-containing ligands; that is very important for drug delivery and creating of tissue-specific MRI contrast agents. The synthesis of the first type hybrid nanoparticles was carried out as follows: magnetite nanoparticles with an average diameter of 9±2 nm were obtained by co-precipitation of iron (II, III) chlorides then they were covered with gold shell by iterative reduction of hydrogen tetrachloroaurate with hydroxylamine hydrochloride. According to the TEM, ICP MS and EDX data, final nanoparticles had an average diameter of 31±4 nm and contained iron even after hydrochloric acid treatment. However, iron signals (K-line, 7,1 keV) were not localized so we can’t speak about one single magnetic core. Described nanoparticles covered with mercapto-PEG acid were non-toxic for human prostate cancer PC-3/ LNCaP cell lines (more than 90% survived cells as compared to control) and had high R2-relaxivity rates (\u3e190 mМ-1s-1) that exceed the transverse relaxation rate of commercial MRI-contrasting agents. These nanoparticles were also used for chymotrypsin enzyme immobilization. The effect of alternating magnetic field on catalytic properties of chymotrypsin immobilized on magnetite nanoparticles, notably the slowdown of catalyzed reaction at the level of 35-40 % was found. The most probable reason for the observed effect is the change of active centers topology on the enzyme surface as a result of its deformation under applied forces. The synthesis of the second type hybrid nanoparticles also involved two steps. Firstly, spherical gold nanoparticles with an average diameter of 9±2 nm were synthesized by the reduction of hydrogen tetrachloroaurate with oleylamine; secondly, they were used as seeds during magnetite synthesis by thermal decomposition of iron pentacarbonyl in octadecene. As a result, so-called dumbbell-like structures were obtained where magnetite (cubes with 25±6 nm diagonal) and gold nanoparticles were connected together pairwise. By HRTEM method (first time for this type of structure) an epitaxial growth of magnetite nanoparticles on gold surface with co-orientation of (111) planes was discovered. These nanoparticles were transferred into water by means of block-copolymer Pluronic F127 then loaded with anti-cancer drug doxorubicin and also PSMA-vector specific for LNCaP cell line. Obtained nanoparticles were found to have moderate toxicity for human prostate cancer cells and got into the intracellular space after 45 minutes of incubation (according to fluorescence microscopy data). These materials are also perspective from MRI point of view (R2-relaxivity rates \u3e70 mМ-1s-1). Thereby, in this work magnetite-gold hybrid nanoparticles, which have a strong potential for biomedical application, particularly in targeted drug delivery and magnetic resonance imaging, were synthesized and characterized. That paves the way to the development of new medicine types – theranostics. The authors knowledge financial support from Ministry of Education and Science of the Russian Federation (14.607.21.0132, RFMEFI60715X0132). This work was also supported by Grant of Ministry of Education and Science of the Russian Federation К1-2014-022, Grant of Russian Scientific Foundation 14-13-00731 and MSU development program 5.13

Mathematical Modelling of the Parameters of Braided Textile Tapes

Braided textile materials are widely used in many industries and agriculture. Braided tapes are used for domestic purposes, in the food industry, in construction, in medicine, in aircraft manufacturing, in electrical engineering, etc. Every braided product must correspond to a unique group of parameters and properties, depending on the initial manufacturing parameters. The production of braided tapes is still insufficiently explored. In the process of designing and manufacturing products with specified parameters, it is necessary to substantiate the formation of braided products. The manufacture of products with specific parameters and properties, and the creation of rational technological modes for that production represent urgent scientific issues to be addressed. One way to solve this problem is to conduct factorial experiments. This article thus presents the results of a factorial experiment, during which the following input parameters were determined based on preliminary studies: type of raw material, the linear density of raw materials and speed of removal of the product from the formation zone. The following were chosen as output parameters: breaking load, breaking elongation, the linear density of tapes, product width and the number of strands per 10 mm. The limits of factor variation were determined for four types of raw materials. Based on the results of the processing of the obtained experimental data, linear mathematical models were developed. The results of the verification of mathematical models indicated that they adequately describe the process of braiding tapes within the intervals determined by the conditions of the experiment. We thus established a connection between the factors of the braiding process and the properties of braided tapes

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

Онтология процессов, ориентированная на верификацию

This paper presents the ontology of the concurrent processes close to Hoare communicating sequential processes. It is the part of the intellectual system for supporting verification of behavioural properties of these processes. Our ontological representation of the processes is oriented both to the application of formal verification methods and to the extraction of information from technical documentation (by our previously developed system of information extraction from a natural language text). We describe the ontology classes and domains that define communicating concurrent processes. These processes are characterized by sets of local and shared variables, a list of actions on these variables which change their values, a list of channels for the process communication (which, in turn, are characterized by the type of reading messages, capacity, ways of writing and reading, and reliability), and also a list of communication actions for sending messages. In addition to the formal mathematical definition of classes and domains of the ontology, examples of descriptions of some ontological classes as well as typical properties and axioms for them are specified in the editor Prot ́eg ́e in the OWL language with the use of the inference rules in the SWRL language. The formal operational semantics of communicating processes is determined on their ontological representation and is given as a labelled transition system. It is reduced to the local operational semantics of separate process instances in the interleaving model. We specialize several types of processes from the subject domain of automatic control systems that model the typical functional elements of the automatic control system (sensors, comparators and regulators) as well as their combinations. The concepts of the specialized ontology are illustrated by the example of a control part for a bottle-filling system.В статье представлена онтология процессов, близких взаимодействующим последовательным процессам Хоара. Она является частью интеллектуальной системы поддержки верификации свойств поведения таких процессов. Наше онтологическое представление процессов ориентировано как на применение формальных методов верификации, так и на извлечение информации из технической документации (с помощью нашей ранее разработанной системы извлечения информации из текстов на естественном языке). Мы описываем классы и домены онтологии, которые определяют взаимодействующие процессы. Эти процессы характеризуются множествами локальных и разделяемых переменных, списком действий над этими переменными, которые изменяют их значения, списком каналов взаимодействия процессов (которые, в свою очередь, характеризуются типом чтения сообщений, емкостью, способами записи и считывания, а также надежностью), списком коммуникационных действий для отправки сообщений. Помимо формального математического определения классов и доменов онтологии, приведены примеры описаний некоторых онтологических классов, а также типовых свойств и аксиом для них в редакторе Prot ́eg ́e на языке OWL с использованием правил вывода на языке SWRL. Для онтологического представления взаимодействующих процессов определяется их формальная операционная семантика, которая задается с использованием помеченной системы переходов. В интерливинговой модели она сводится к локальной операционной семантике отдельных экземпляров процессов. Представлена специализация онтологии для некоторых типов процессов из предметной области систем автоматического управления, моделирующих типовые функциональные элементы системы автоматического управления (датчики, сравнивающие устройства и регулирующие устройства), а также их комбинации. Понятия специализированной онтологии иллюстрируются на примере управляющей части системы розлива бутылок

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

Методы специализации онтологии процессов, ориентированной на верификацию

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 specialized 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 Prot´eg´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.Удобная для пользователя формальная спецификация и верификация параллельных и распределённых систем, принадлежащих различным предметным областям, таким как системы автоматического управления, телекоммуникации, бизнес-процессы, являются активными темами исследований в силу их практической значимости. В этой статье мы представляем методы разработки специализированных ориентированных на верификацию онтологий процессов, которые используются для описания параллельных и распределенных систем предметных областей. Одним из преимуществ таких онтологий является их формальная семантика, которая делает возможной формальную верификацию описанных систем. Наш метод основан на абстрактной онтологии процессов, ориентированной на верификацию. Мы используем два метода специализации абстрактной онтологии процессов. Декларативный метод с помощью специализации классов исходной онтологии, введения новых декларативных классов, а также системы аксиом задаёт ограничения для классов и отношений абстрактной онтологии. Конструктивный метод использует техники семантической разметки и сопоставления с образцом, чтобы связать понятия предметной области с классами абстрактной онтологии процессов. Мы даём подробные онтологические спецификации этих техник. Наши методы сохраняют формальную семантику исходной онтологии процессов и, следовательно, возможность применения формальных методов верификации к специализированным онтологиям процессов. Мы показываем, что конструктивный метод является уточнением декларативного метода. Построение онтологии типовых элементов систем автоматического управления иллюстрирует наши методы: разработано декларативное описание классов и ограничений специализированной онтологии в системе Protege на языке OWL с использованием правил вывода на языке SWRL и построена система шаблонов семантической разметки, которая реализует типовые элементы систем автоматического управления